From 4a1c2d9c7c5cb370eea0df964d537b60d29a4191 Mon Sep 17 00:00:00 2001
From: bjorn3 <17426603+bjorn3@users.noreply.github.com>
Date: Fri, 10 Feb 2023 18:08:39 +0000
Subject: [PATCH] Fix signaling available_token_condvar when a new token is
 received
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This slightly improves performance on systems with many cores and
barely affects systems with few cores.

My laptop (2 core + HT):
Before:
Benchmark 2: RUSTC=rustc /home/bjorn/Projects/cg_clif2/./dist/cargo-clif build --manifest-path /home/bjorn/Projects/cg_clif2/./download/simple-raytracer/Cargo.toml --target-dir /home/bjorn/Projects/cg_clif2/./build/simple_raytracer
  Time (mean ± σ):     12.042 s ±  0.313 s    [User: 29.434 s, System: 4.720 s]
  Range (min … max):   11.670 s … 12.795 s    10 runs

After:
Benchmark 2: RUSTC=rustc /home/bjorn/Projects/cg_clif2/./dist/cargo-clif build --manifest-path /home/bjorn/Projects/cg_clif2/./download/simple-raytracer/Cargo.toml --target-dir /home/bjorn/Projects/cg_clif2/./build/simple_raytracer
  Time (mean ± σ):     12.037 s ±  0.384 s    [User: 29.960 s, System: 4.722 s]
  Range (min … max):   11.673 s … 12.769 s    10 runs

Dev desktop (32 cores)
Before:
Benchmark 2: RUSTC=rustc /home/gh-bjorn3/cg_clif/./dist/cargo-clif build --manifest-path /home/gh-bjorn3/cg_clif/./download/simple-raytracer/Cargo.toml --target-dir /home/gh-bjorn3/cg_clif/./build/simple_raytracer
  Time (mean ± σ):     10.425 s ±  0.104 s    [User: 25.877 s, System: 5.513 s]
  Range (min … max):   10.267 s … 10.640 s    10 runs

After:
Benchmark 2: RUSTC=rustc /home/gh-bjorn3/cg_clif/./dist/cargo-clif build --manifest-path /home/gh-bjorn3/cg_clif/./download/simple-raytracer/Cargo.toml --target-dir /home/gh-bjorn3/cg_clif/./build/simple_raytracer
  Time (mean ± σ):     10.212 s ±  0.100 s    [User: 25.918 s, System: 5.555 s]
  Range (min … max):   10.079 s … 10.362 s    10 runs
---
 src/concurrency_limiter.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/concurrency_limiter.rs b/src/concurrency_limiter.rs
index f855e20e0a1a..203219a8a754 100644
--- a/src/concurrency_limiter.rs
+++ b/src/concurrency_limiter.rs
@@ -32,7 +32,7 @@ impl ConcurrencyLimiter {
         ConcurrencyLimiter {
             helper_thread: Some(helper_thread),
             state,
-            available_token_condvar: Arc::new(Condvar::new()),
+            available_token_condvar,
             finished: false,
         }
     }