From 4f9c5c00bbf3219ed52f1ff812aa6d08ed0eefe3 Mon Sep 17 00:00:00 2001
From: Janis <janis@nirgendwo.xyz>
Date: Thu, 20 Feb 2025 21:51:16 +0100
Subject: [PATCH] cacheline aligned heartbeat atomics

---
 src/praetor/mod.rs | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/src/praetor/mod.rs b/src/praetor/mod.rs
index 32fdf8d..2ec47a6 100644
--- a/src/praetor/mod.rs
+++ b/src/praetor/mod.rs
@@ -752,6 +752,7 @@ use std::{
     time::Duration,
 };
 
+use crossbeam::utils::CachePadded;
 use job::*;
 use parking_lot::{Condvar, Mutex};
 use util::DropGuard;
@@ -760,7 +761,7 @@ pub struct Scope {
     join_count: Cell<usize>,
     context: Arc<Context>,
     index: usize,
-    heartbeat: Arc<AtomicBool>,
+    heartbeat: Arc<CachePadded<AtomicBool>>,
     queue: UnsafeCell<JobList>,
 }
 
@@ -1058,7 +1059,7 @@ struct Context {
 
 struct SharedContext {
     jobs: BTreeMap<usize, NonNull<Job>>,
-    heartbeats: BTreeMap<usize, Weak<AtomicBool>>,
+    heartbeats: BTreeMap<usize, Weak<CachePadded<AtomicBool>>>,
     // monotonic increasing id
     heartbeats_id: usize,
     should_stop: bool,
@@ -1067,11 +1068,11 @@ struct SharedContext {
 unsafe impl Send for SharedContext {}
 
 impl SharedContext {
-    fn new_heartbeat(&mut self) -> (Arc<AtomicBool>, usize) {
+    fn new_heartbeat(&mut self) -> (Arc<CachePadded<AtomicBool>>, usize) {
         let index = self.heartbeats_id;
         self.heartbeats_id.checked_add(1).unwrap();
 
-        let is_set = Arc::new(AtomicBool::new(false));
+        let is_set = Arc::new(CachePadded::new(AtomicBool::new(false)));
         let weak = Arc::downgrade(&is_set);
 
         self.heartbeats.insert(index, weak);