From c4292fb2beb00ab21c74f846b56ecc99ebe12422 Mon Sep 17 00:00:00 2001
From: Nick Fitzgerald <fitzgen@gmail.com>
Date: Wed, 29 Apr 2020 14:40:54 -0700
Subject: [PATCH] Allow setting the number of filetest threads via the
 CRANELIFT_FILETESTS_THREADS env var

---
 cranelift/filetests/src/concurrent.rs | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/cranelift/filetests/src/concurrent.rs b/cranelift/filetests/src/concurrent.rs
index 30e2c94cfe..67592ed03e 100644
--- a/cranelift/filetests/src/concurrent.rs
+++ b/cranelift/filetests/src/concurrent.rs
@@ -50,7 +50,16 @@ impl ConcurrentRunner {
 
         heartbeat_thread(reply_tx.clone());
 
-        let handles = (0..num_cpus::get())
+        let num_threads = std::env::var("CRANELIFT_FILETESTS_THREADS")
+            .ok()
+            .map(|s| {
+                use std::str::FromStr;
+                let n = usize::from_str(&s).unwrap();
+                assert!(n > 0);
+                n
+            })
+            .unwrap_or_else(|| num_cpus::get());
+        let handles = (0..num_threads)
             .map(|num| worker_thread(num, request_mutex.clone(), reply_tx.clone()))
             .collect();