From 6ffe521421d645d507618f8befc4da6f3c0d0374 Mon Sep 17 00:00:00 2001
From: Carl Lerche <me@carllerche.com>
Date: Thu, 1 Jun 2023 14:42:49 -0700
Subject: [PATCH] ci: fix spurious CI failure

PR #5720 introduced runtime self-tuning. It included a test that
attempts to verify self-tuning logic. The test is heavily reliant on
timing details. This patch attempts to make the test a bit more reliable
by not assuming tuning will converge within a set amount of time.
---
 .github/workflows/ci.yml   |  2 +-
 tokio/tests/rt_threaded.rs | 25 +++++++++----------------
 2 files changed, 10 insertions(+), 17 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 7aa75b7855d..f8fd34ce487 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -294,7 +294,7 @@ jobs:
           toolchain: ${{ env.rust_nightly }}
       - uses: Swatinem/rust-cache@v2
       - name: asan
-        run: cargo test --workspace --all-features --target x86_64-unknown-linux-gnu --tests -- --test-threads 1
+        run: cargo test --workspace --all-features --target x86_64-unknown-linux-gnu --tests -- --test-threads 1 --nocapture
         env:
           RUSTFLAGS: -Z sanitizer=address
           # Ignore `trybuild` errors as they are irrelevant and flaky on nightly
diff --git a/tokio/tests/rt_threaded.rs b/tokio/tests/rt_threaded.rs
index 85ecdf4271d..fcfec74a32a 100644
--- a/tokio/tests/rt_threaded.rs
+++ b/tokio/tests/rt_threaded.rs
@@ -627,7 +627,6 @@ fn test_tuning() {
     }
 
     // Now, hammer the injection queue until the interval drops.
-    let mut i = 0;
     let mut n = 0;
     loop {
         let curr = interval.load(Relaxed);
@@ -645,18 +644,16 @@ fn test_tuning() {
             break;
         }
 
-        let counter = counter.clone();
-        let interval = interval.clone();
+        if Arc::strong_count(&interval) < 5_000 {
+            let counter = counter.clone();
+            let interval = interval.clone();
 
-        if i <= 5_000 {
-            i += 1;
             rt.spawn(async move {
                 let prev = counter.swap(0, Relaxed);
                 interval.store(prev, Relaxed);
             });
+
             std::thread::yield_now();
-        } else {
-            std::thread::sleep(Duration::from_micros(500));
         }
     }
 
@@ -682,7 +679,6 @@ fn test_tuning() {
     }
 
     // Now, hammer the injection queue until the interval reaches the expected range.
-    let mut i = 0;
     let mut n = 0;
     loop {
         let curr = interval.load(Relaxed);
@@ -697,20 +693,17 @@ fn test_tuning() {
             break;
         }
 
-        let counter = counter.clone();
-        let interval = interval.clone();
+        if Arc::strong_count(&interval) <= 5_000 {
+            let counter = counter.clone();
+            let interval = interval.clone();
 
-        if i <= 5_000 {
-            i += 1;
             rt.spawn(async move {
                 let prev = counter.swap(0, Relaxed);
                 interval.store(prev, Relaxed);
             });
-
-            std::thread::yield_now();
-        } else {
-            std::thread::sleep(Duration::from_micros(500));
         }
+
+        std::thread::yield_now();
     }
 
     flag.store(false, Relaxed);