main
25 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
Alex Crichton
|
63d80fc509 |
Remove the need to have a Store for an InstancePre (#5683)
* Remove the need to have a `Store` for an `InstancePre` This commit relaxes a requirement of the `InstancePre` API, notably its construction via `Linker::instantiate_pre`. Previously this function required a `Store<T>` to be present to be able to perform type-checking on the contents of the linker, and now this requirement has been removed. Items stored within a linker are either a `HostFunc`, which has type information inside of it, or an `Extern`, which doesn't have type information inside of it. Due to the usage of `Extern` this is why a `Store` was required during the `InstancePre` construction process, it's used to extract the type of an `Extern`. This commit implements a solution where the type information of an `Extern` is stored alongside the `Extern` itself, meaning that the `InstancePre` construction process no longer requires a `Store<T>`. One caveat of this implementation is that some items, such as tables and memories, technically have a "dynamic type" where during type checking their current size is consulted to match against the minimum size required of an import. This no longer works when using `Linker::instantiate_pre` as the current size used is the one when it was inserted into the linker rather than the one available at instantiation time. It's hoped, however, that this is a relatively esoteric use case that doesn't impact many real-world users. Additionally note that this is an API-breaking change. Not only is the `Store` argument removed from `Linker::instantiate_pre`, but some other methods such as `Linker::define` grew a `Store` argument as the type needs to be extracted when an item is inserted into a linker. Closes #5675 * Fix the C API * Fix benchmark compilation * Add C API docs * Update crates/wasmtime/src/linker.rs Co-authored-by: Andrew Brown <andrew.brown@intel.com> --------- Co-authored-by: Andrew Brown <andrew.brown@intel.com> |
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|
Andrew Brown
|
4899537328 |
bench: add more WASI benchmarks (#5309)
* bench: add more WASI benchmarks This follows up on #5274 to add several more scenarios with which to benchmark WASI performance: - `open-file.wat`: opens and closes a file - `read-file.wat`: opens a file, reads 4K bytes from it, then closes it - `read-dir.wat`: reads a directory's entries Each benchmark is hand-crafted WAT to more clearly control what WASI calls are made. As with #5274, these modules' sole entry point takes a parameter indicating the number of iterations to run in order to use `criterion`'s `iter_custom` feature. * fix: reduce expected size of directory entries |
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|
Alex Crichton
|
b0939f6626 |
Remove explicit S type parameters (#5275)
* Remove explicit `S` type parameters This commit removes the explicit `S` type parameter on `Func::typed` and `Instance::get_typed_func`. Historical versions of Rust required that this be a type parameter but recent rustcs support a mixture of explicit type parameters and `impl Trait`. This removes, at callsites, a superfluous `, _` argument which otherwise never needs specification. * Fix mdbook examples |
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|
Andrew Brown
|
8426904129 |
bench: benchmark several common WASI scenarios (#5274)
In order to properly understand the impact of providing thread-safe implmentations of WASI contexts (#5235), we need benchmarks that measure the current performance of WASI calls using Wiggle. This change adds several common WASI scenarios as WAT files (see `benches/wasi/*.wat`) and benchmarks them with `criterion`. Using `criterion`'s `iter_custom`, the WAT file runs the desired number of benchmark iterations internally and the total duration of the runs is divided to get the average time for each loop iteration. Why WAT? When compiling these benchmarks from Rust to `wasm32-wasi`, the output files are large, contain other WASI imports than the desired ones, and overall it is difficult to tell if we are measuring what we expect. By hand-writing the WAT, it is (slightly) more clear what each benchmark is doing. |
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|
Alex Crichton
|
b14551d7ca |
Refactor configuration for the pooling allocator (#5205)
This commit changes the APIs in the `wasmtime` crate for configuring the pooling allocator. I plan on adding a few more configuration options in the near future and the current structure was feeling unwieldy for adding these new abstractions. The previous `struct`-based API has been replaced with a builder-style API in a similar shape as to `Config`. This is done to help make it easier to add more configuration options in the future through adding more methods as opposed to adding more field which could break prior initializations. |
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|
Nick Fitzgerald
|
a2f846f124 |
Don't re-capture backtraces when propagating traps through host frames (#5049)
* Add a benchmark for traps with many Wasm<-->host calls on the stack * Add a test for expected Wasm stack traces with Wasm<--host calls on the stack when we trap * Don't re-capture backtraces when propagating traps through host frames This fixes some accidentally quadratic code where we would re-capture a Wasm stack trace (takes `O(n)` time) every time we propagated a trap through a host frame back to Wasm (can happen `O(n)` times). And `O(n) * O(n) = O(n^2)`, of course. Whoops. After this commit, it trapping with a call stack that is `n` frames deep of Wasm-to-host-to-Wasm calls just captures a single backtrace and is therefore just a proper `O(n)` time operation, as it is intended to be. Now we explicitly track whether we need to capture a Wasm backtrace or not when raising a trap. This unfortunately isn't as straightforward as one might hope, however, because of the split between `wasmtime::Trap` and `wasmtime_runtime::Trap`. We need to decide whether or not to capture a Wasm backtrace inside `wasmtime_runtime` but in order to determine whether to do that or not we need to reflect on the `anyhow::Error` and see if it is a `wasmtime::Trap` that already has a backtrace or not. This can't be done the straightforward way because it would introduce a cyclic dependency between the `wasmtime` and `wasmtime-runtime` crates. We can't merge those two `Trap` types-- at least not without effectively merging the whole `wasmtime` and `wasmtime-runtime` crates together, which would be a good idea in a perfect world but would be a *ton* of ocean boiling from where we currently are -- because `wasmtime::Trap` does symbolication of stack traces which relies on module registration information data that resides inside the `wasmtime` crate and therefore can't be moved into `wasmtime-runtime`. We resolve this problem by adding a boolean to `wasmtime_runtime::raise_user_trap` that controls whether we should capture a Wasm backtrace or not, and then determine whether we need a backtrace or not at each of that function's call sites, which are in `wasmtime` and therefore can do the reflection to determine whether the user trap already has a backtrace or not. Phew! Fixes #5037 * debug assert that we don't record unnecessary backtraces for traps * Add assertions around `needs_backtrace` Unfortunately we can't do debug_assert_eq!(needs_backtrace, trap.inner.backtrace.get().is_some()); because `needs_backtrace` doesn't consider whether Wasm backtraces have been disabled via config. * Consolidate `needs_backtrace` calculation followed by calling `raise_user_trap` into one place |
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Nick Fitzgerald
|
46782b18c2 |
wasmtime: Implement fast Wasm stack walking (#4431)
* Always preserve frame pointers in Wasmtime
This allows us to efficiently and simply capture Wasm stacks without maintaining
and synchronizing any safety-critical side tables between the compiler and the
runtime.
* wasmtime: Implement fast Wasm stack walking
Why do we want Wasm stack walking to be fast? Because we capture stacks whenever
there is a trap and traps actually happen fairly frequently with short-lived
programs and WASI's `exit`.
Previously, we would rely on generating the system unwind info (e.g.
`.eh_frame`) and using the system unwinder (via the `backtrace`crate) to walk
the full stack and filter out any non-Wasm stack frames. This can,
unfortunately, be slow for two primary reasons:
1. The system unwinder is doing `O(all-kinds-of-frames)` work rather than
`O(wasm-frames)` work.
2. System unwind info and the system unwinder need to be much more general than
a purpose-built stack walker for Wasm needs to be. It has to handle any kind of
stack frame that any compiler might emit where as our Wasm frames are emitted by
Cranelift and always have frame pointers. This translates into implementation
complexity and general overhead. There can also be unnecessary-for-our-use-cases
global synchronization and locks involved, further slowing down stack walking in
the presence of multiple threads trying to capture stacks in parallel.
This commit introduces a purpose-built stack walker for traversing just our Wasm
frames. To find all the sequences of Wasm-to-Wasm stack frames, and ignore
non-Wasm stack frames, we keep a linked list of `(entry stack pointer, exit
frame pointer)` pairs. This linked list is maintained via Wasm-to-host and
host-to-Wasm trampolines. Within a sequence of Wasm-to-Wasm calls, we can use
frame pointers (which Cranelift preserves) to find the next older Wasm frame on
the stack, and we keep doing this until we reach the entry stack pointer,
meaning that the next older frame will be a host frame.
The trampolines need to avoid a couple stumbling blocks. First, they need to be
compiled ahead of time, since we may not have access to a compiler at
runtime (e.g. if the `cranelift` feature is disabled) but still want to be able
to call functions that have already been compiled and get stack traces for those
functions. Usually this means we would compile the appropriate trampolines
inside `Module::new` and the compiled module object would hold the
trampolines. However, we *also* need to support calling host functions that are
wrapped into `wasmtime::Func`s and there doesn't exist *any* ahead-of-time
compiled module object to hold the appropriate trampolines:
```rust
// Define a host function.
let func_type = wasmtime::FuncType::new(
vec![wasmtime::ValType::I32],
vec![wasmtime::ValType::I32],
);
let func = Func::new(&mut store, func_type, |_, params, results| {
// ...
Ok(())
});
// Call that host function.
let mut results = vec![wasmtime::Val::I32(0)];
func.call(&[wasmtime::Val::I32(0)], &mut results)?;
```
Therefore, we define one host-to-Wasm trampoline and one Wasm-to-host trampoline
in assembly that work for all Wasm and host function signatures. These
trampolines are careful to only use volatile registers, avoid touching any
register that is an argument in the calling convention ABI, and tail call to the
target callee function. This allows forwarding any set of arguments and any
returns to and from the callee, while also allowing us to maintain our linked
list of Wasm stack and frame pointers before transferring control to the
callee. These trampolines are not used in Wasm-to-Wasm calls, only when crossing
the host-Wasm boundary, so they do not impose overhead on regular calls. (And if
using one trampoline for all host-Wasm boundary crossing ever breaks branch
prediction enough in the CPU to become any kind of bottleneck, we can do fun
things like have multiple copies of the same trampoline and choose a random copy
for each function, sharding the functions across branch predictor entries.)
Finally, this commit also ends the use of a synthetic `Module` and allocating a
stubbed out `VMContext` for host functions. Instead, we define a
`VMHostFuncContext` with its own magic value, similar to `VMComponentContext`,
specifically for host functions.
<h2>Benchmarks</h2>
<h3>Traps and Stack Traces</h3>
Large improvements to taking stack traces on traps, ranging from shaving off 64%
to 99.95% of the time it used to take.
<details>
```
multi-threaded-traps/0 time: [2.5686 us 2.5808 us 2.5934 us]
thrpt: [0.0000 elem/s 0.0000 elem/s 0.0000 elem/s]
change:
time: [-85.419% -85.153% -84.869%] (p = 0.00 < 0.05)
thrpt: [+560.90% +573.56% +585.84%]
Performance has improved.
Found 8 outliers among 100 measurements (8.00%)
4 (4.00%) high mild
4 (4.00%) high severe
multi-threaded-traps/1 time: [2.9021 us 2.9167 us 2.9322 us]
thrpt: [341.04 Kelem/s 342.86 Kelem/s 344.58 Kelem/s]
change:
time: [-91.455% -91.294% -91.096%] (p = 0.00 < 0.05)
thrpt: [+1023.1% +1048.6% +1070.3%]
Performance has improved.
Found 6 outliers among 100 measurements (6.00%)
1 (1.00%) high mild
5 (5.00%) high severe
multi-threaded-traps/2 time: [2.9996 us 3.0145 us 3.0295 us]
thrpt: [660.18 Kelem/s 663.47 Kelem/s 666.76 Kelem/s]
change:
time: [-94.040% -93.910% -93.762%] (p = 0.00 < 0.05)
thrpt: [+1503.1% +1542.0% +1578.0%]
Performance has improved.
Found 5 outliers among 100 measurements (5.00%)
5 (5.00%) high severe
multi-threaded-traps/4 time: [5.5768 us 5.6052 us 5.6364 us]
thrpt: [709.68 Kelem/s 713.63 Kelem/s 717.25 Kelem/s]
change:
time: [-93.193% -93.121% -93.052%] (p = 0.00 < 0.05)
thrpt: [+1339.2% +1353.6% +1369.1%]
Performance has improved.
multi-threaded-traps/8 time: [8.6408 us 9.1212 us 9.5438 us]
thrpt: [838.24 Kelem/s 877.08 Kelem/s 925.84 Kelem/s]
change:
time: [-94.754% -94.473% -94.202%] (p = 0.00 < 0.05)
thrpt: [+1624.7% +1709.2% +1806.1%]
Performance has improved.
multi-threaded-traps/16 time: [10.152 us 10.840 us 11.545 us]
thrpt: [1.3858 Melem/s 1.4760 Melem/s 1.5761 Melem/s]
change:
time: [-97.042% -96.823% -96.577%] (p = 0.00 < 0.05)
thrpt: [+2821.5% +3048.1% +3281.1%]
Performance has improved.
Found 1 outliers among 100 measurements (1.00%)
1 (1.00%) high mild
many-modules-registered-traps/1
time: [2.6278 us 2.6361 us 2.6447 us]
thrpt: [378.11 Kelem/s 379.35 Kelem/s 380.55 Kelem/s]
change:
time: [-85.311% -85.108% -84.909%] (p = 0.00 < 0.05)
thrpt: [+562.65% +571.51% +580.76%]
Performance has improved.
Found 9 outliers among 100 measurements (9.00%)
3 (3.00%) high mild
6 (6.00%) high severe
many-modules-registered-traps/8
time: [2.6294 us 2.6460 us 2.6623 us]
thrpt: [3.0049 Melem/s 3.0235 Melem/s 3.0425 Melem/s]
change:
time: [-85.895% -85.485% -85.022%] (p = 0.00 < 0.05)
thrpt: [+567.63% +588.95% +608.95%]
Performance has improved.
Found 8 outliers among 100 measurements (8.00%)
3 (3.00%) high mild
5 (5.00%) high severe
many-modules-registered-traps/64
time: [2.6218 us 2.6329 us 2.6452 us]
thrpt: [24.195 Melem/s 24.308 Melem/s 24.411 Melem/s]
change:
time: [-93.629% -93.551% -93.470%] (p = 0.00 < 0.05)
thrpt: [+1431.4% +1450.6% +1469.5%]
Performance has improved.
Found 3 outliers among 100 measurements (3.00%)
3 (3.00%) high mild
many-modules-registered-traps/512
time: [2.6569 us 2.6737 us 2.6923 us]
thrpt: [190.17 Melem/s 191.50 Melem/s 192.71 Melem/s]
change:
time: [-99.277% -99.268% -99.260%] (p = 0.00 < 0.05)
thrpt: [+13417% +13566% +13731%]
Performance has improved.
Found 4 outliers among 100 measurements (4.00%)
4 (4.00%) high mild
many-modules-registered-traps/4096
time: [2.7258 us 2.7390 us 2.7535 us]
thrpt: [1.4876 Gelem/s 1.4955 Gelem/s 1.5027 Gelem/s]
change:
time: [-99.956% -99.955% -99.955%] (p = 0.00 < 0.05)
thrpt: [+221417% +223380% +224881%]
Performance has improved.
Found 2 outliers among 100 measurements (2.00%)
1 (1.00%) high mild
1 (1.00%) high severe
many-stack-frames-traps/1
time: [1.4658 us 1.4719 us 1.4784 us]
thrpt: [676.39 Kelem/s 679.38 Kelem/s 682.21 Kelem/s]
change:
time: [-90.368% -89.947% -89.586%] (p = 0.00 < 0.05)
thrpt: [+860.23% +894.72% +938.21%]
Performance has improved.
Found 8 outliers among 100 measurements (8.00%)
5 (5.00%) high mild
3 (3.00%) high severe
many-stack-frames-traps/8
time: [2.4772 us 2.4870 us 2.4973 us]
thrpt: [3.2034 Melem/s 3.2167 Melem/s 3.2294 Melem/s]
change:
time: [-85.550% -85.370% -85.199%] (p = 0.00 < 0.05)
thrpt: [+575.65% +583.51% +592.03%]
Performance has improved.
Found 8 outliers among 100 measurements (8.00%)
4 (4.00%) high mild
4 (4.00%) high severe
many-stack-frames-traps/64
time: [10.109 us 10.171 us 10.236 us]
thrpt: [6.2525 Melem/s 6.2925 Melem/s 6.3309 Melem/s]
change:
time: [-78.144% -77.797% -77.336%] (p = 0.00 < 0.05)
thrpt: [+341.22% +350.38% +357.55%]
Performance has improved.
Found 7 outliers among 100 measurements (7.00%)
5 (5.00%) high mild
2 (2.00%) high severe
many-stack-frames-traps/512
time: [126.16 us 126.54 us 126.96 us]
thrpt: [4.0329 Melem/s 4.0461 Melem/s 4.0583 Melem/s]
change:
time: [-65.364% -64.933% -64.453%] (p = 0.00 < 0.05)
thrpt: [+181.32% +185.17% +188.71%]
Performance has improved.
Found 4 outliers among 100 measurements (4.00%)
4 (4.00%) high severe
```
</details>
<h3>Calls</h3>
There is, however, a small regression in raw Wasm-to-host and host-to-Wasm call
performance due the new trampolines. It seems to be on the order of about 2-10
nanoseconds per call, depending on the benchmark.
I believe this regression is ultimately acceptable because
1. this overhead will be vastly dominated by whatever work a non-nop callee
actually does,
2. we will need these trampolines, or something like them, when implementing the
Wasm exceptions proposal to do things like translate Wasm's exceptions into
Rust's `Result`s,
3. and because the performance improvements to trapping and capturing stack
traces are of such a larger magnitude than this call regressions.
<details>
```
sync/no-hook/host-to-wasm - typed - nop
time: [28.683 ns 28.757 ns 28.844 ns]
change: [+16.472% +17.183% +17.904%] (p = 0.00 < 0.05)
Performance has regressed.
Found 10 outliers among 100 measurements (10.00%)
1 (1.00%) low mild
4 (4.00%) high mild
5 (5.00%) high severe
sync/no-hook/host-to-wasm - untyped - nop
time: [42.515 ns 42.652 ns 42.841 ns]
change: [+12.371% +14.614% +17.462%] (p = 0.00 < 0.05)
Performance has regressed.
Found 11 outliers among 100 measurements (11.00%)
1 (1.00%) high mild
10 (10.00%) high severe
sync/no-hook/host-to-wasm - unchecked - nop
time: [33.936 ns 34.052 ns 34.179 ns]
change: [+25.478% +26.938% +28.369%] (p = 0.00 < 0.05)
Performance has regressed.
Found 9 outliers among 100 measurements (9.00%)
7 (7.00%) high mild
2 (2.00%) high severe
sync/no-hook/host-to-wasm - typed - nop-params-and-results
time: [34.290 ns 34.388 ns 34.502 ns]
change: [+40.802% +42.706% +44.526%] (p = 0.00 < 0.05)
Performance has regressed.
Found 13 outliers among 100 measurements (13.00%)
5 (5.00%) high mild
8 (8.00%) high severe
sync/no-hook/host-to-wasm - untyped - nop-params-and-results
time: [62.546 ns 62.721 ns 62.919 ns]
change: [+2.5014% +3.6319% +4.8078%] (p = 0.00 < 0.05)
Performance has regressed.
Found 12 outliers among 100 measurements (12.00%)
2 (2.00%) high mild
10 (10.00%) high severe
sync/no-hook/host-to-wasm - unchecked - nop-params-and-results
time: [42.609 ns 42.710 ns 42.831 ns]
change: [+20.966% +22.282% +23.475%] (p = 0.00 < 0.05)
Performance has regressed.
Found 11 outliers among 100 measurements (11.00%)
4 (4.00%) high mild
7 (7.00%) high severe
sync/hook-sync/host-to-wasm - typed - nop
time: [29.546 ns 29.675 ns 29.818 ns]
change: [+20.693% +21.794% +22.836%] (p = 0.00 < 0.05)
Performance has regressed.
Found 5 outliers among 100 measurements (5.00%)
3 (3.00%) high mild
2 (2.00%) high severe
sync/hook-sync/host-to-wasm - untyped - nop
time: [45.448 ns 45.699 ns 45.961 ns]
change: [+17.204% +18.514% +19.590%] (p = 0.00 < 0.05)
Performance has regressed.
Found 14 outliers among 100 measurements (14.00%)
4 (4.00%) high mild
10 (10.00%) high severe
sync/hook-sync/host-to-wasm - unchecked - nop
time: [34.334 ns 34.437 ns 34.558 ns]
change: [+23.225% +24.477% +25.886%] (p = 0.00 < 0.05)
Performance has regressed.
Found 12 outliers among 100 measurements (12.00%)
5 (5.00%) high mild
7 (7.00%) high severe
sync/hook-sync/host-to-wasm - typed - nop-params-and-results
time: [36.594 ns 36.763 ns 36.974 ns]
change: [+41.967% +47.261% +52.086%] (p = 0.00 < 0.05)
Performance has regressed.
Found 12 outliers among 100 measurements (12.00%)
3 (3.00%) high mild
9 (9.00%) high severe
sync/hook-sync/host-to-wasm - untyped - nop-params-and-results
time: [63.541 ns 63.831 ns 64.194 ns]
change: [-4.4337% -0.6855% +2.7134%] (p = 0.73 > 0.05)
No change in performance detected.
Found 8 outliers among 100 measurements (8.00%)
6 (6.00%) high mild
2 (2.00%) high severe
sync/hook-sync/host-to-wasm - unchecked - nop-params-and-results
time: [43.968 ns 44.169 ns 44.437 ns]
change: [+18.772% +21.802% +24.623%] (p = 0.00 < 0.05)
Performance has regressed.
Found 15 outliers among 100 measurements (15.00%)
3 (3.00%) high mild
12 (12.00%) high severe
async/no-hook/host-to-wasm - typed - nop
time: [4.9612 us 4.9743 us 4.9889 us]
change: [+9.9493% +11.911% +13.502%] (p = 0.00 < 0.05)
Performance has regressed.
Found 10 outliers among 100 measurements (10.00%)
6 (6.00%) high mild
4 (4.00%) high severe
async/no-hook/host-to-wasm - untyped - nop
time: [5.0030 us 5.0211 us 5.0439 us]
change: [+10.841% +11.873% +12.977%] (p = 0.00 < 0.05)
Performance has regressed.
Found 10 outliers among 100 measurements (10.00%)
3 (3.00%) high mild
7 (7.00%) high severe
async/no-hook/host-to-wasm - typed - nop-params-and-results
time: [4.9273 us 4.9468 us 4.9700 us]
change: [+4.7381% +6.8445% +8.8238%] (p = 0.00 < 0.05)
Performance has regressed.
Found 14 outliers among 100 measurements (14.00%)
5 (5.00%) high mild
9 (9.00%) high severe
async/no-hook/host-to-wasm - untyped - nop-params-and-results
time: [5.1151 us 5.1338 us 5.1555 us]
change: [+9.5335% +11.290% +13.044%] (p = 0.00 < 0.05)
Performance has regressed.
Found 16 outliers among 100 measurements (16.00%)
3 (3.00%) high mild
13 (13.00%) high severe
async/hook-sync/host-to-wasm - typed - nop
time: [4.9330 us 4.9394 us 4.9467 us]
change: [+10.046% +11.038% +12.035%] (p = 0.00 < 0.05)
Performance has regressed.
Found 12 outliers among 100 measurements (12.00%)
5 (5.00%) high mild
7 (7.00%) high severe
async/hook-sync/host-to-wasm - untyped - nop
time: [5.0073 us 5.0183 us 5.0310 us]
change: [+9.3828% +10.565% +11.752%] (p = 0.00 < 0.05)
Performance has regressed.
Found 8 outliers among 100 measurements (8.00%)
3 (3.00%) high mild
5 (5.00%) high severe
async/hook-sync/host-to-wasm - typed - nop-params-and-results
time: [4.9610 us 4.9839 us 5.0097 us]
change: [+9.0857% +11.513% +14.359%] (p = 0.00 < 0.05)
Performance has regressed.
Found 13 outliers among 100 measurements (13.00%)
7 (7.00%) high mild
6 (6.00%) high severe
async/hook-sync/host-to-wasm - untyped - nop-params-and-results
time: [5.0995 us 5.1272 us 5.1617 us]
change: [+9.3600% +11.506% +13.809%] (p = 0.00 < 0.05)
Performance has regressed.
Found 10 outliers among 100 measurements (10.00%)
6 (6.00%) high mild
4 (4.00%) high severe
async-pool/no-hook/host-to-wasm - typed - nop
time: [2.4242 us 2.4316 us 2.4396 us]
change: [+7.8756% +8.8803% +9.8346%] (p = 0.00 < 0.05)
Performance has regressed.
Found 8 outliers among 100 measurements (8.00%)
5 (5.00%) high mild
3 (3.00%) high severe
async-pool/no-hook/host-to-wasm - untyped - nop
time: [2.5102 us 2.5155 us 2.5210 us]
change: [+12.130% +13.194% +14.270%] (p = 0.00 < 0.05)
Performance has regressed.
Found 12 outliers among 100 measurements (12.00%)
4 (4.00%) high mild
8 (8.00%) high severe
async-pool/no-hook/host-to-wasm - typed - nop-params-and-results
time: [2.4203 us 2.4310 us 2.4440 us]
change: [+4.0380% +6.3623% +8.7534%] (p = 0.00 < 0.05)
Performance has regressed.
Found 14 outliers among 100 measurements (14.00%)
5 (5.00%) high mild
9 (9.00%) high severe
async-pool/no-hook/host-to-wasm - untyped - nop-params-and-results
time: [2.5501 us 2.5593 us 2.5700 us]
change: [+8.8802% +10.976% +12.937%] (p = 0.00 < 0.05)
Performance has regressed.
Found 16 outliers among 100 measurements (16.00%)
5 (5.00%) high mild
11 (11.00%) high severe
async-pool/hook-sync/host-to-wasm - typed - nop
time: [2.4135 us 2.4190 us 2.4254 us]
change: [+8.3640% +9.3774% +10.435%] (p = 0.00 < 0.05)
Performance has regressed.
Found 11 outliers among 100 measurements (11.00%)
6 (6.00%) high mild
5 (5.00%) high severe
async-pool/hook-sync/host-to-wasm - untyped - nop
time: [2.5172 us 2.5248 us 2.5357 us]
change: [+11.543% +12.750% +13.982%] (p = 0.00 < 0.05)
Performance has regressed.
Found 8 outliers among 100 measurements (8.00%)
1 (1.00%) high mild
7 (7.00%) high severe
async-pool/hook-sync/host-to-wasm - typed - nop-params-and-results
time: [2.4214 us 2.4353 us 2.4532 us]
change: [+1.5158% +5.0872% +8.6765%] (p = 0.00 < 0.05)
Performance has regressed.
Found 15 outliers among 100 measurements (15.00%)
2 (2.00%) high mild
13 (13.00%) high severe
async-pool/hook-sync/host-to-wasm - untyped - nop-params-and-results
time: [2.5499 us 2.5607 us 2.5748 us]
change: [+10.146% +12.459% +14.919%] (p = 0.00 < 0.05)
Performance has regressed.
Found 18 outliers among 100 measurements (18.00%)
3 (3.00%) high mild
15 (15.00%) high severe
sync/no-hook/wasm-to-host - nop - typed
time: [6.6135 ns 6.6288 ns 6.6452 ns]
change: [+37.927% +38.837% +39.869%] (p = 0.00 < 0.05)
Performance has regressed.
Found 7 outliers among 100 measurements (7.00%)
2 (2.00%) high mild
5 (5.00%) high severe
sync/no-hook/wasm-to-host - nop-params-and-results - typed
time: [15.930 ns 15.993 ns 16.067 ns]
change: [+3.9583% +5.6286% +7.2430%] (p = 0.00 < 0.05)
Performance has regressed.
Found 12 outliers among 100 measurements (12.00%)
11 (11.00%) high mild
1 (1.00%) high severe
sync/no-hook/wasm-to-host - nop - untyped
time: [20.596 ns 20.640 ns 20.690 ns]
change: [+4.3293% +5.2047% +6.0935%] (p = 0.00 < 0.05)
Performance has regressed.
Found 10 outliers among 100 measurements (10.00%)
5 (5.00%) high mild
5 (5.00%) high severe
sync/no-hook/wasm-to-host - nop-params-and-results - untyped
time: [42.659 ns 42.882 ns 43.159 ns]
change: [-2.1466% -0.5079% +1.2554%] (p = 0.58 > 0.05)
No change in performance detected.
Found 15 outliers among 100 measurements (15.00%)
1 (1.00%) high mild
14 (14.00%) high severe
sync/no-hook/wasm-to-host - nop - unchecked
time: [10.671 ns 10.691 ns 10.713 ns]
change: [+83.911% +87.620% +92.062%] (p = 0.00 < 0.05)
Performance has regressed.
Found 9 outliers among 100 measurements (9.00%)
2 (2.00%) high mild
7 (7.00%) high severe
sync/no-hook/wasm-to-host - nop-params-and-results - unchecked
time: [11.136 ns 11.190 ns 11.263 ns]
change: [-29.719% -28.446% -27.029%] (p = 0.00 < 0.05)
Performance has improved.
Found 14 outliers among 100 measurements (14.00%)
4 (4.00%) high mild
10 (10.00%) high severe
sync/hook-sync/wasm-to-host - nop - typed
time: [6.7964 ns 6.8087 ns 6.8226 ns]
change: [+21.531% +24.206% +27.331%] (p = 0.00 < 0.05)
Performance has regressed.
Found 14 outliers among 100 measurements (14.00%)
4 (4.00%) high mild
10 (10.00%) high severe
sync/hook-sync/wasm-to-host - nop-params-and-results - typed
time: [15.865 ns 15.921 ns 15.985 ns]
change: [+4.8466% +6.3330% +7.8317%] (p = 0.00 < 0.05)
Performance has regressed.
Found 16 outliers among 100 measurements (16.00%)
3 (3.00%) high mild
13 (13.00%) high severe
sync/hook-sync/wasm-to-host - nop - untyped
time: [21.505 ns 21.587 ns 21.677 ns]
change: [+8.0908% +9.1943% +10.254%] (p = 0.00 < 0.05)
Performance has regressed.
Found 8 outliers among 100 measurements (8.00%)
4 (4.00%) high mild
4 (4.00%) high severe
sync/hook-sync/wasm-to-host - nop-params-and-results - untyped
time: [44.018 ns 44.128 ns 44.261 ns]
change: [-1.4671% -0.0458% +1.2443%] (p = 0.94 > 0.05)
No change in performance detected.
Found 14 outliers among 100 measurements (14.00%)
5 (5.00%) high mild
9 (9.00%) high severe
sync/hook-sync/wasm-to-host - nop - unchecked
time: [11.264 ns 11.326 ns 11.387 ns]
change: [+80.225% +81.659% +83.068%] (p = 0.00 < 0.05)
Performance has regressed.
Found 6 outliers among 100 measurements (6.00%)
3 (3.00%) high mild
3 (3.00%) high severe
sync/hook-sync/wasm-to-host - nop-params-and-results - unchecked
time: [11.816 ns 11.865 ns 11.920 ns]
change: [-29.152% -28.040% -26.957%] (p = 0.00 < 0.05)
Performance has improved.
Found 14 outliers among 100 measurements (14.00%)
8 (8.00%) high mild
6 (6.00%) high severe
async/no-hook/wasm-to-host - nop - typed
time: [6.6221 ns 6.6385 ns 6.6569 ns]
change: [+43.618% +44.755% +45.965%] (p = 0.00 < 0.05)
Performance has regressed.
Found 13 outliers among 100 measurements (13.00%)
6 (6.00%) high mild
7 (7.00%) high severe
async/no-hook/wasm-to-host - nop-params-and-results - typed
time: [15.884 ns 15.929 ns 15.983 ns]
change: [+3.5987% +5.2053% +6.7846%] (p = 0.00 < 0.05)
Performance has regressed.
Found 16 outliers among 100 measurements (16.00%)
3 (3.00%) high mild
13 (13.00%) high severe
async/no-hook/wasm-to-host - nop - untyped
time: [20.615 ns 20.702 ns 20.821 ns]
change: [+6.9799% +8.1212% +9.2819%] (p = 0.00 < 0.05)
Performance has regressed.
Found 10 outliers among 100 measurements (10.00%)
2 (2.00%) high mild
8 (8.00%) high severe
async/no-hook/wasm-to-host - nop-params-and-results - untyped
time: [41.956 ns 42.207 ns 42.521 ns]
change: [-4.3057% -2.7730% -1.2428%] (p = 0.00 < 0.05)
Performance has improved.
Found 14 outliers among 100 measurements (14.00%)
3 (3.00%) high mild
11 (11.00%) high severe
async/no-hook/wasm-to-host - nop - unchecked
time: [10.440 ns 10.474 ns 10.513 ns]
change: [+83.959% +85.826% +87.541%] (p = 0.00 < 0.05)
Performance has regressed.
Found 11 outliers among 100 measurements (11.00%)
5 (5.00%) high mild
6 (6.00%) high severe
async/no-hook/wasm-to-host - nop-params-and-results - unchecked
time: [11.476 ns 11.512 ns 11.554 ns]
change: [-29.857% -28.383% -26.978%] (p = 0.00 < 0.05)
Performance has improved.
Found 12 outliers among 100 measurements (12.00%)
1 (1.00%) low mild
6 (6.00%) high mild
5 (5.00%) high severe
async/no-hook/wasm-to-host - nop - async-typed
time: [26.427 ns 26.478 ns 26.532 ns]
change: [+6.5730% +7.4676% +8.3983%] (p = 0.00 < 0.05)
Performance has regressed.
Found 9 outliers among 100 measurements (9.00%)
2 (2.00%) high mild
7 (7.00%) high severe
async/no-hook/wasm-to-host - nop-params-and-results - async-typed
time: [28.557 ns 28.693 ns 28.880 ns]
change: [+1.9099% +3.7332% +5.9731%] (p = 0.00 < 0.05)
Performance has regressed.
Found 15 outliers among 100 measurements (15.00%)
1 (1.00%) high mild
14 (14.00%) high severe
async/hook-sync/wasm-to-host - nop - typed
time: [6.7488 ns 6.7630 ns 6.7784 ns]
change: [+19.935% +22.080% +23.683%] (p = 0.00 < 0.05)
Performance has regressed.
Found 9 outliers among 100 measurements (9.00%)
4 (4.00%) high mild
5 (5.00%) high severe
async/hook-sync/wasm-to-host - nop-params-and-results - typed
time: [15.928 ns 16.031 ns 16.149 ns]
change: [+5.5188% +6.9567% +8.3839%] (p = 0.00 < 0.05)
Performance has regressed.
Found 11 outliers among 100 measurements (11.00%)
9 (9.00%) high mild
2 (2.00%) high severe
async/hook-sync/wasm-to-host - nop - untyped
time: [21.930 ns 22.114 ns 22.296 ns]
change: [+4.6674% +7.7588% +10.375%] (p = 0.00 < 0.05)
Performance has regressed.
Found 4 outliers among 100 measurements (4.00%)
3 (3.00%) high mild
1 (1.00%) high severe
async/hook-sync/wasm-to-host - nop-params-and-results - untyped
time: [42.684 ns 42.858 ns 43.081 ns]
change: [-5.2957% -3.4693% -1.6217%] (p = 0.00 < 0.05)
Performance has improved.
Found 14 outliers among 100 measurements (14.00%)
2 (2.00%) high mild
12 (12.00%) high severe
async/hook-sync/wasm-to-host - nop - unchecked
time: [11.026 ns 11.053 ns 11.086 ns]
change: [+70.751% +72.378% +73.961%] (p = 0.00 < 0.05)
Performance has regressed.
Found 10 outliers among 100 measurements (10.00%)
5 (5.00%) high mild
5 (5.00%) high severe
async/hook-sync/wasm-to-host - nop-params-and-results - unchecked
time: [11.840 ns 11.900 ns 11.982 ns]
change: [-27.977% -26.584% -24.887%] (p = 0.00 < 0.05)
Performance has improved.
Found 18 outliers among 100 measurements (18.00%)
3 (3.00%) high mild
15 (15.00%) high severe
async/hook-sync/wasm-to-host - nop - async-typed
time: [27.601 ns 27.709 ns 27.882 ns]
change: [+8.1781% +9.1102% +10.030%] (p = 0.00 < 0.05)
Performance has regressed.
Found 11 outliers among 100 measurements (11.00%)
2 (2.00%) low mild
3 (3.00%) high mild
6 (6.00%) high severe
async/hook-sync/wasm-to-host - nop-params-and-results - async-typed
time: [28.955 ns 29.174 ns 29.413 ns]
change: [+1.1226% +3.0366% +5.1126%] (p = 0.00 < 0.05)
Performance has regressed.
Found 13 outliers among 100 measurements (13.00%)
7 (7.00%) high mild
6 (6.00%) high severe
async-pool/no-hook/wasm-to-host - nop - typed
time: [6.5626 ns 6.5733 ns 6.5851 ns]
change: [+40.561% +42.307% +44.514%] (p = 0.00 < 0.05)
Performance has regressed.
Found 9 outliers among 100 measurements (9.00%)
5 (5.00%) high mild
4 (4.00%) high severe
async-pool/no-hook/wasm-to-host - nop-params-and-results - typed
time: [15.820 ns 15.886 ns 15.969 ns]
change: [+4.1044% +5.7928% +7.7122%] (p = 0.00 < 0.05)
Performance has regressed.
Found 17 outliers among 100 measurements (17.00%)
4 (4.00%) high mild
13 (13.00%) high severe
async-pool/no-hook/wasm-to-host - nop - untyped
time: [20.481 ns 20.521 ns 20.566 ns]
change: [+6.7962% +7.6950% +8.7612%] (p = 0.00 < 0.05)
Performance has regressed.
Found 11 outliers among 100 measurements (11.00%)
6 (6.00%) high mild
5 (5.00%) high severe
async-pool/no-hook/wasm-to-host - nop-params-and-results - untyped
time: [41.834 ns 41.998 ns 42.189 ns]
change: [-3.8185% -2.2687% -0.7541%] (p = 0.01 < 0.05)
Change within noise threshold.
Found 13 outliers among 100 measurements (13.00%)
3 (3.00%) high mild
10 (10.00%) high severe
async-pool/no-hook/wasm-to-host - nop - unchecked
time: [10.353 ns 10.380 ns 10.414 ns]
change: [+82.042% +84.591% +87.205%] (p = 0.00 < 0.05)
Performance has regressed.
Found 7 outliers among 100 measurements (7.00%)
4 (4.00%) high mild
3 (3.00%) high severe
async-pool/no-hook/wasm-to-host - nop-params-and-results - unchecked
time: [11.123 ns 11.168 ns 11.228 ns]
change: [-30.813% -29.285% -27.874%] (p = 0.00 < 0.05)
Performance has improved.
Found 12 outliers among 100 measurements (12.00%)
11 (11.00%) high mild
1 (1.00%) high severe
async-pool/no-hook/wasm-to-host - nop - async-typed
time: [27.442 ns 27.528 ns 27.638 ns]
change: [+7.5215% +9.9795% +12.266%] (p = 0.00 < 0.05)
Performance has regressed.
Found 18 outliers among 100 measurements (18.00%)
3 (3.00%) high mild
15 (15.00%) high severe
async-pool/no-hook/wasm-to-host - nop-params-and-results - async-typed
time: [29.014 ns 29.148 ns 29.312 ns]
change: [+2.0227% +3.4722% +4.9047%] (p = 0.00 < 0.05)
Performance has regressed.
Found 7 outliers among 100 measurements (7.00%)
6 (6.00%) high mild
1 (1.00%) high severe
async-pool/hook-sync/wasm-to-host - nop - typed
time: [6.7916 ns 6.8116 ns 6.8325 ns]
change: [+20.937% +22.050% +23.281%] (p = 0.00 < 0.05)
Performance has regressed.
Found 11 outliers among 100 measurements (11.00%)
5 (5.00%) high mild
6 (6.00%) high severe
async-pool/hook-sync/wasm-to-host - nop-params-and-results - typed
time: [15.917 ns 15.975 ns 16.051 ns]
change: [+4.6404% +6.4217% +8.3075%] (p = 0.00 < 0.05)
Performance has regressed.
Found 16 outliers among 100 measurements (16.00%)
5 (5.00%) high mild
11 (11.00%) high severe
async-pool/hook-sync/wasm-to-host - nop - untyped
time: [21.558 ns 21.612 ns 21.679 ns]
change: [+8.1158% +9.1409% +10.217%] (p = 0.00 < 0.05)
Performance has regressed.
Found 9 outliers among 100 measurements (9.00%)
2 (2.00%) high mild
7 (7.00%) high severe
async-pool/hook-sync/wasm-to-host - nop-params-and-results - untyped
time: [42.475 ns 42.614 ns 42.775 ns]
change: [-6.3613% -4.4709% -2.7647%] (p = 0.00 < 0.05)
Performance has improved.
Found 18 outliers among 100 measurements (18.00%)
3 (3.00%) high mild
15 (15.00%) high severe
async-pool/hook-sync/wasm-to-host - nop - unchecked
time: [11.150 ns 11.195 ns 11.247 ns]
change: [+74.424% +77.056% +79.811%] (p = 0.00 < 0.05)
Performance has regressed.
Found 14 outliers among 100 measurements (14.00%)
3 (3.00%) high mild
11 (11.00%) high severe
async-pool/hook-sync/wasm-to-host - nop-params-and-results - unchecked
time: [11.639 ns 11.695 ns 11.760 ns]
change: [-30.212% -29.023% -27.954%] (p = 0.00 < 0.05)
Performance has improved.
Found 15 outliers among 100 measurements (15.00%)
7 (7.00%) high mild
8 (8.00%) high severe
async-pool/hook-sync/wasm-to-host - nop - async-typed
time: [27.480 ns 27.712 ns 27.984 ns]
change: [+2.9764% +6.5061% +9.8914%] (p = 0.00 < 0.05)
Performance has regressed.
Found 8 outliers among 100 measurements (8.00%)
6 (6.00%) high mild
2 (2.00%) high severe
async-pool/hook-sync/wasm-to-host - nop-params-and-results - async-typed
time: [29.218 ns 29.380 ns 29.600 ns]
change: [+5.2283% +7.7247% +10.822%] (p = 0.00 < 0.05)
Performance has regressed.
Found 16 outliers among 100 measurements (16.00%)
2 (2.00%) high mild
14 (14.00%) high severe
```
</details>
* Add s390x support for frame pointer-based stack walking
* wasmtime: Allow `Caller::get_export` to get all exports
* fuzzing: Add a fuzz target to check that our stack traces are correct
We generate Wasm modules that keep track of their own stack as they call and
return between functions, and then we periodically check that if the host
captures a backtrace, it matches what the Wasm module has recorded.
* Remove VM offsets for `VMHostFuncContext` since it isn't used by JIT code
* Add doc comment with stack walking implementation notes
* Document the extra state that can be passed to `wasmtime_runtime::Backtrace` methods
* Add extensive comments for stack walking function
* Factor architecture-specific bits of stack walking out into modules
* Initialize store-related fields in a vmctx to null when there is no store yet
Rather than leaving them as uninitialized data.
* Use `set_callee` instead of manually setting the vmctx field
* Use a more informative compile error message for unsupported architectures
* Document unsafety of `prepare_host_to_wasm_trampoline`
* Use `bti c` instead of `hint #34` in inline aarch64 assembly
* Remove outdated TODO comment
* Remove setting of `last_wasm_exit_fp` in `set_jit_trap`
This is no longer needed as the value is plumbed through to the backtrace code
directly now.
* Only set the stack limit once, in the face of re-entrancy into Wasm
* Add comments for s390x-specific stack walking bits
* Use the helper macro for all libcalls
If we forget to use it, and then trigger a GC from the libcall, that means we
could miss stack frames when walking the stack, fail to find live GC refs, and
then get use after free bugs. Much less risky to always use the helper macro
that takes care of all of that for us.
* Use the `asm_sym!` macro in Wasm-to-libcall trampolines
This macro handles the macOS-specific underscore prefix stuff for us.
* wasmtime: add size and align to `externref` assertion error message
* Extend the `stacks` fuzzer to have host frames in between Wasm frames
This way we get one or more contiguous sequences of Wasm frames on the stack,
instead of exactly one.
* Add documentation for aarch64-specific backtrace helpers
* Clarify that we only support little-endian aarch64 in trampoline comment
* Use `.machine z13` in s390x assembly file
Since apparently our CI machines have pretty old assemblers that don't have
`.machine z14`. This should be fine though since these trampolines don't make
use of anything that is introduced in z14.
* Fix aarch64 build
* Fix macOS build
* Document the `asm_sym!` macro
* Add windows support to the `wasmtime-asm-macros` crate
* Add windows support to host<--->Wasm trampolines
* Fix trap handler build on windows
* Run `rustfmt` on s390x trampoline source file
* Temporarily disable some assertions about a trap's backtrace in the component model tests
Follow up to re-enable this and fix the associated issue:
https://github.com/bytecodealliance/wasmtime/issues/4535
* Refactor libcall definitions with less macros
This refactors the `libcall!` macro to use the
`foreach_builtin_function!` macro to define all of the trampolines.
Additionally the macro surrounding each libcall itself is no longer
necessary and helps avoid too many macros.
* Use `VMOpaqueContext::from_vm_host_func_context` in `VMHostFuncContext::new`
* Move `backtrace` module to be submodule of `traphandlers`
This avoids making some things `pub(crate)` in `traphandlers` that really
shouldn't be.
* Fix macOS aarch64 build
* Use "i64" instead of "word" in aarch64-specific file
* Save/restore entry SP and exit FP/return pointer in the face of panicking imported host functions
Also clean up assertions surrounding our saved entry/exit registers.
* Put "typed" vs "untyped" in the same position of call benchmark names
Regardless if we are doing wasm-to-host or host-to-wasm
* Fix stacks test case generator build for new `wasm-encoder`
* Fix build for s390x
* Expand libcalls in s390x asm
* Disable more parts of component tests now that backtrace assertions are a bit tighter
* Remove assertion that can maybe fail on s390x
Co-authored-by: Ulrich Weigand <ulrich.weigand@de.ibm.com>
Co-authored-by: Alex Crichton <alex@alexcrichton.com>
|
||
|
Nick Fitzgerald
|
7000b0a4cf |
wasmtime: Add criterion micro benchmarks for traps (#4398)
* wasmtime: Rename host->wasm trampolines As we introduce new types of trampolines, having clear names for our existing trampolines will be helpful. * Fix typo in docs for `VMCOMPONENT_MAGIC` * wasmtime: Add criterion micro benchmarks for traps |
||
|
Alex Crichton
|
82a31680d6 |
Use a StoreOpaque during backtraces for metadata (#4325)
Previous to this commit Wasmtime would use the `GlobalModuleRegistry` when learning information about a trap such as its trap code, the symbols for each frame, etc. This has a downside though of holding a global read-write lock for the duration of this operation which hinders registration of new modules in parallel. In addition there was a fair amount of internal duplication between this "global module registry" and the store-local module registry. Finally relying on global state for information like this gets a bit more brittle over time as it seems best to scope global queries to precisely what's necessary rather than holding extra information. With the refactoring in wasm backtraces done in #4183 it's now possible to always have a `StoreOpaque` reference when a backtrace is collected for symbolication and otherwise Trap-identification purposes. This commit adds a `StoreOpaque` parameter to the `Trap::from_runtime` constructor and then plumbs that everywhere. Note that while doing this I changed the internal `traphandlers::lazy_per_thread_init` function to no longer return a `Result` and instead just `panic!` on Unix if memory couldn't be allocated for a stack. This removed quite a lot of error-handling code for a case that's expected to quite rarely happen. If necessary in the future we can add a fallible initialization point but this feels like a better default balance for the code here. With a `StoreOpaque` in use when a trap is being symbolicated that means we have a `ModuleRegistry` which can be used for queries and such. This meant that the `GlobalModuleRegistry` state could largely be dismantled and moved to per-`Store` state (within the `ModuleRegistry`, mostly just moving methods around). The final state is that the global rwlock is not exclusively scoped around insertions/deletions/`is_wasm_trap_pc` which is just a lookup and atomic add. Otherwise symbolication for a backtrace exclusively uses store-local state now (as intended). The original motivation for this commit was that frame information lookup and pieces were looking to get somewhat complicated with the addition of components which are a new vector of traps coming out of Cranelift-generated code. My hope is that by having a `Store` around for more operations it's easier to plumb all this through. |
||
|
Alex Crichton
|
f4b9020913 |
Change wasm-to-host trampolines to take the values_vec size (#4192)
* Change wasm-to-host trampolines to take the values_vec size This commit changes the ABI of wasm-to-host trampolines, which are only used right now for functions created with `Func::new`, to pass along the size of the `values_vec` argument. Previously the trampoline simply received `*mut ValRaw` and assumed that it was the appropriate size. By receiving a size as well we can thread through `&mut [ValRaw]` internally instead of `*mut ValRaw`. The original motivation for this is that I'm planning to leverage these trampolines for the component model for host-defined functions. Out of an abundance of caution of making sure that everything lines up I wanted to be able to write down asserts about the size received at runtime compared to the size expected. This overall led me to the desire to thread this size parameter through on the assumption that it would not impact performance all that much. I ran two benchmarks locally from the `call.rs` benchmark and got: * `sync/no-hook/wasm-to-host - nop - unchecked` - no change * `sync/no-hook/wasm-to-host - nop-params-and-results - unchecked` - 5% slower This is what I roughly expected in that if nothing actually reads the new parameter (e.g. no arguments) then threading through the parameter is effectively otherwise free. Otherwise though accesses to the `ValRaw` storage is now bounds-checked internally in Wasmtime instead of assuming it's valid, leading to the 5% slowdown (~9.6ns to ~10.3ns). If this becomes a peformance bottleneck for a particular use case then we should be fine to remove the bounds checking here or otherwise only bounds check in debug mode, otherwise I plan on leaving this as-is. Of particular note this also changes the C API for `*_unchecked` functions where the C callback now receives the size of the array as well. * Add docs |
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Alex Crichton
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a02a609528 |
Make ValRaw fields private (#4186)
* Make `ValRaw` fields private Force accessing to go through constructors and accessors to localize the knowledge about little-endian-ness. This is spawned since I made a mistake in #4039 about endianness. * Fix some tests * Component model changes |
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Benjamin Bouvier
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6e828df632 |
Remove unused SourceLoc in many Mach data structures (#4180)
* Remove unused srcloc in MachReloc * Remove unused srcloc in MachTrap * Use `into_iter` on array in bench code to suppress a warning * Remove unused srcloc in MachCallSite |
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Alex Crichton
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3f3afb455e |
Remove support for userfaultfd (#4040)
This commit removes support for the `userfaultfd` or "uffd" syscall on Linux. This support was originally added for users migrating from Lucet to Wasmtime, but the recent developments of kernel-supported copy-on-write support for memory initialization wound up being more appropriate for these use cases than usefaultfd. The main reason for moving to copy-on-write initialization are: * The `userfaultfd` feature was never necessarily intended for this style of use case with wasm and was susceptible to subtle and rare bugs that were extremely difficult to track down. We were never 100% certain that there were kernel bugs related to userfaultfd but the suspicion never went away. * Handling faults with userfaultfd was always slow and single-threaded. Only one thread could handle faults and traveling to user-space to handle faults is inherently slower than handling them all in the kernel. The single-threaded aspect in particular presented a significant scaling bottleneck for embeddings that want to run many wasm instances in parallel. * One of the major benefits of userfaultfd was lazy initialization of wasm linear memory which is also achieved with the copy-on-write initialization support we have right now. * One of the suspected benefits of userfaultfd was less frobbing of the kernel vma structures when wasm modules are instantiated. Currently the copy-on-write support has a mitigation where we attempt to reuse the memory images where possible to avoid changing vma structures. When comparing this to userfaultfd's performance it was found that kernel modifications of vmas aren't a worrisome bottleneck so copy-on-write is suitable for this as well. Overall there are no remaining benefits that userfaultfd gives that copy-on-write doesn't, and copy-on-write solves a major downsides of userfaultfd, the scaling issue with a single faulting thread. Additionally copy-on-write support seems much more robust in terms of kernel implementation since it's only using standard memory-management syscalls which are heavily exercised. Finally copy-on-write support provides a new bonus where read-only memory in WebAssembly can be mapped directly to the same kernel cache page, even amongst many wasm instances of the same module, which was never possible with userfaultfd. In light of all this it's expected that all users of userfaultfd should migrate to the copy-on-write initialization of Wasmtime (which is enabled by default). |
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Alex Crichton
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7c3dd3398d |
Reduce benchmark runtime on CI (#3896)
After adding the `call`-oriented benchmark recently I just noticed that running benchmarks on CI is taking 30+ minutes which is not intended. Instead of running a full benchmark run on CI (which I believe we're not looking at anyway) instead only run the benchmarks for a single iteration to ensure they still work but otherwise don't collect statistics about them. Additionally cap the number of parallel instantiations to 16 to avoid running tons of tests for machines with lots of cpus. |
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Alex Crichton
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8c9c72caaa |
Add a benchmark for measuring call overhead (#3883)
The goal of this new benchmark, `call`, is to help us measure the overhead of both calling into WebAssembly from the host as well as calling the host from WebAssembly. There's lots of various ways to measure this so this benchmark is a bit large but should hopefully be pretty thorough. It's expected that this benchmark will rarely be run in its entirety but rather only a subset of the benchmarks will be run at any one given time. Some metrics measured here are: * Typed vs Untyped vs Unchecked - testing the cost of both calling wasm with these various methods as well as having wasm call the host where the host function is defined with these various methods. * With and without `call_hook` - helps to measure the overhead of the `Store::call_hook` API. * Synchronous and Asynchronous - measures the overhead of calling into WebAssembly asynchronously (with and without the pooling allocator) in addition to defining host APIs in various methods when wasm is called asynchronously. Currently all the numbers are as expected, notably: * Host calling WebAssembly is ~25ns of overhead * WebAssembly calling the host is ~3ns of overhead * "Unchecked" is a bit slower than "typed", and "Untyped" is slower than unchecked. * Asynchronous wasm calling a synchronous host function has ~3ns of overhead (nothing more than usual). * Asynchronous calls are much slower, on the order of 2-3us due to `madvise`. Lots of other fiddly bits that can be measured here, but this will hopefully help establish a benchmark through which we can measure in the future in addition to measuring changes such as #3876 |
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Alex Crichton
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15bb0c6903 |
Remove the ModuleLimits pooling configuration structure (#3837)
* Remove the `ModuleLimits` pooling configuration structure
This commit is an attempt to improve the usability of the pooling
allocator by removing the need to configure a `ModuleLimits` structure.
Internally this structure has limits on all forms of wasm constructs but
this largely bottoms out in the size of an allocation for an instance in
the instance pooling allocator. Maintaining this list of limits can be
cumbersome as modules may get tweaked over time and there's otherwise no
real reason to limit the number of globals in a module since the main
goal is to limit the memory consumption of a `VMContext` which can be
done with a memory allocation limit rather than fine-tuned control over
each maximum and minimum.
The new approach taken in this commit is to remove `ModuleLimits`. Some
fields, such as `tables`, `table_elements` , `memories`, and
`memory_pages` are moved to `InstanceLimits` since they're still
enforced at runtime. A new field `size` is added to `InstanceLimits`
which indicates, in bytes, the maximum size of the `VMContext`
allocation. If the size of a `VMContext` for a module exceeds this value
then instantiation will fail.
This involved adding a few more checks to `{Table, Memory}::new_static`
to ensure that the minimum size is able to fit in the allocation, since
previously modules were validated at compile time of the module that
everything fit and that validation no longer happens (it happens at
runtime).
A consequence of this commit is that Wasmtime will have no built-in way
to reject modules at compile time if they'll fail to be instantiated
within a particular pooling allocator configuration. Instead a module
must attempt instantiation see if a failure happens.
* Fix benchmark compiles
* Fix some doc links
* Fix a panic by ensuring modules have limited tables/memories
* Review comments
* Add back validation at `Module` time instantiation is possible
This allows for getting an early signal at compile time that a module
will never be instantiable in an engine with matching settings.
* Provide a better error message when sizes are exceeded
Improve the error message when an instance size exceeds the maximum by
providing a breakdown of where the bytes are all going and why the large
size is being requested.
* Try to fix test in qemu
* Flag new test as 64-bit only
Sizes are all specific to 64-bit right now
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Alex Crichton
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1cb08d4e67 |
Minor instantiation benchmark updates (#3790)
This commit has a few minor updates and some improvements to the instantiation benchmark harness: * A `once_cell::unsync::Lazy` type is now used to guard creation of modules/engines/etc. This enables running singular benchmarks to be much faster since the benchmark no longer compiles all other benchmarks that are filtered out. Unfortunately I couldn't find a way in criterion to test whether a `BenchmarkId` is filtered out or not so we rely on the runtime laziness to initialize on the first run for benchmarks that do so. * All files located in `benches/instantiation` are now loaded for benchmarking instead of a hardcoded list. This makes it a bit easier to throw files into the directory and have them benchmarked instead of having to recompile when working with new files. * Finally a module deserialization benchmark was added to measure the time it takes to deserialize a precompiled module from disk (inspired by discussion on #3787) While I was at it I also upped some limits to be able to instantiate cfallin's `spidermonkey.wasm`. |
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Alex Crichton
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43b37944ff |
Tweak parallelism and the instantiation benchmark (#3775)
Currently the "sequential" and "parallel" benchmarks reports somewhat different timings. For sequential it's time-to-instantiate, but for parallel it's time-to-instantiate-10k instances. The parallelism in the parallel benchmark can also theoretically be affected by rayon's work-stealing. For example if rayon doesn't actually do any work stealing at all then this ends up being a sequential test again. Otherwise though it's possible for some threads to finish much earlier as rayon isn't guaranteed to keep threads busy. This commit applies a few updates to the benchmark: * First an `InstancePre<T>` is now used instead of a `Linker<T>` to front-load type-checking and avoid that on each instantiation (and this is generally the fastest path to instantiate right now). * Next the instantiation benchmark is changed to measure one instantiation-per-iteration to measure per-instance instantiation to better compare with sequential numbers. * Finally rayon is removed in favor of manually creating background threads that infinitely do work until we tell them to stop. These background threads are guaranteed to be working for the entire time the benchmark is executing and should theoretically exhibit what the situation that there's N units of work all happening at once. I also applied some minor updates here such as having the parallel instantiation defined conditionally for multiple modules as well as upping the limits of the pooling allocator to handle a large module (rustpython.wasm) that I threw at it. |
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Nick Fitzgerald
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e3a423c3e8 |
Remove some uses of foo.expect(&format!(...)) pattern
This eagerly evaluates the `format!` and produces a `String` with a heap allocation, regardless whether `foo` is `Some`/`Ok` or `None`/`Err`. Using `foo.unwrap_or_else(|| panic!(...))` makes it so that the error message formatting is only evaluated if `foo` is `None`/`Err`. |
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Alex Crichton
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7ce46043dc |
Add guard pages to the front of linear memories (#2977)
* Add guard pages to the front of linear memories
This commit implements a safety feature for Wasmtime to place guard
pages before the allocation of all linear memories. Guard pages placed
after linear memories are typically present for performance (at least)
because it can help elide bounds checks. Guard pages before a linear
memory, however, are never strictly needed for performance or features.
The intention of a preceding guard page is to help insulate against bugs
in Cranelift or other code generators, such as CVE-2021-32629.
This commit adds a `Config::guard_before_linear_memory` configuration
option, defaulting to `true`, which indicates whether guard pages should
be present both before linear memories as well as afterwards. Guard
regions continue to be controlled by
`{static,dynamic}_memory_guard_size` methods.
The implementation here affects both on-demand allocated memories as
well as the pooling allocator for memories. For on-demand memories this
adjusts the size of the allocation as well as adjusts the calculations
for the base pointer of the wasm memory. For the pooling allocator this
will place a singular extra guard region at the very start of the
allocation for memories. Since linear memories in the pooling allocator
are contiguous every memory already had a preceding guard region in
memory, it was just the previous memory's guard region afterwards. Only
the first memory needed this extra guard.
I've attempted to write some tests to help test all this, but this is
all somewhat tricky to test because the settings are pretty far away
from the actual behavior. I think, though, that the tests added here
should help cover various use cases and help us have confidence in
tweaking the various `Config` settings beyond their defaults.
Note that this also contains a semantic change where
`InstanceLimits::memory_reservation_size` has been removed. Instead this
field is now inferred from the `static_memory_maximum_size` and guard
size settings. This should hopefully remove some duplication in these
settings, canonicalizing on the guard-size/static-size settings as the
way to control memory sizes and virtual reservations.
* Update config docs
* Fix a typo
* Fix benchmark
* Fix wasmtime-runtime tests
* Fix some more tests
* Try to fix uffd failing test
* Review items
* Tweak 32-bit defaults
Makes the pooling allocator a bit more reasonable by default on 32-bit
with these settings.
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Pat Hickey
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035d541fd9 | add docs | ||
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Pat Hickey
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2a4c51b77d | switch eager vs lazy instantiation to a criterion bench | ||
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Alex Crichton
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7a1b7cdf92 |
Implement RFC 11: Redesigning Wasmtime's APIs (#2897)
Implement Wasmtime's new API as designed by RFC 11. This is quite a large commit which has had lots of discussion externally, so for more information it's best to read the RFC thread and the PR thread. |
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Pat Hickey
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0f5bdc6497 |
only wasi_cap_std_sync and wasi_tokio need to define WasiCtxBuilders (#2917)
* wasmtime-wasi: re-exporting this WasiCtxBuilder was shadowing the right one wasi-common's WasiCtxBuilder is really only useful wasi_cap_std_sync and wasi_tokio to implement their own Builder on top of. This re-export of wasi-common's is 1. not useful and 2. shadow's the re-export of the right one in sync::*. * wasi-common: eliminate WasiCtxBuilder, make the builder methods on WasiCtx instead * delete wasi-common::WasiCtxBuilder altogether just put those methods directly on &mut WasiCtx. As a bonus, the sync and tokio WasiCtxBuilder::build functions are no longer fallible! * bench fixes * more test fixes |
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Peter Huene
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1b8efa7bbd |
Implement simple benchmarks for instantiation.
This adds benchmarks around module instantiation using criterion. Both the default (i.e. on-demand) and pooling allocators are tested sequentially and in parallel using a thread pool. Instantiation is tested with an empty module, a module with a single page linear memory, a larger linear memory with a data initializer, and a "hello world" Rust WASI program. |