From 4dc2e8a0adc10906ff6a0c16e6ec46bc73d15a14 Mon Sep 17 00:00:00 2001
From: Jake Shadle <jake.shadle@embark-studios.com>
Date: Wed, 20 Apr 2022 12:01:36 +0200
Subject: [PATCH] Try harder to use user cpu time

---
 src/bin/test.rs | 23 ++++++++++++++++-------
 1 file changed, 16 insertions(+), 7 deletions(-)

diff --git a/src/bin/test.rs b/src/bin/test.rs
index 2bfe7cfc..a0793785 100644
--- a/src/bin/test.rs
+++ b/src/bin/test.rs
@@ -352,15 +352,24 @@ mod mac {
             let task = mach2::traps::mach_task_self();
             let thread = mach2::mach_init::mach_thread_self();
 
-            // Busy loop for 1 second just so we accrue user thread time
-            std::thread::spawn(move || {
+            fn count(seconds: u64) {
+                // Busy loop for 1 second just so we accrue user thread time
                 let start = std::time::Instant::now();
-                while (std::time::Instant::now() - start).as_secs() < 1 {
-                    eprint!(".");
+                let mut counter = 0;
+                while (std::time::Instant::now() - start).as_secs() < seconds {
+                    counter += 1;
+                    std::thread::sleep(std::time::Duration::from_millis(10));
                 }
-            })
-            .join()
-            .unwrap();
+
+                eprintln!("{:?} counted to {}", std::thread::current().id(), counter);
+            }
+
+            // Start some threads
+            let threads = (0..20).map(|_| std::thread::spawn(move || count(1)));
+
+            for thread in threads {
+                thread.join().unwrap();
+            }
 
             println!("{task} {thread}");