From 3530e5ab8ac647e713243e55ee8836f2c2a92c81 Mon Sep 17 00:00:00 2001
From: Russel Arbore <russel.jma@gmail.com>
Date: Tue, 4 Mar 2025 18:52:10 -0600
Subject: [PATCH] Spin barrier that might be useful later
---
hercules_rt/src/lib.rs | 28 ++++++++++++++++++++++++++++
1 file changed, 28 insertions(+)
diff --git a/hercules_rt/src/lib.rs b/hercules_rt/src/lib.rs
index a5954ca0..9265808b 100644
--- a/hercules_rt/src/lib.rs
+++ b/hercules_rt/src/lib.rs
@@ -5,6 +5,7 @@ use std::future::Future;
use std::marker::PhantomData;
use std::ptr::{copy_nonoverlapping, write_bytes, NonNull};
use std::slice::{from_raw_parts, from_raw_parts_mut};
+use std::sync::atomic::{AtomicUsize, Ordering};
use std::sync::OnceLock;
/*
@@ -928,3 +929,30 @@ unsafe impl GlobalAlloc for AlignedAlloc {
#[global_allocator]
static A: AlignedAlloc = AlignedAlloc;
+
+pub struct SpinBarrier {
+ num: usize,
+ waiting: AtomicUsize,
+ gen: AtomicUsize,
+}
+
+impl SpinBarrier {
+ pub const fn new(num: usize) -> Self {
+ SpinBarrier {
+ num,
+ waiting: AtomicUsize::new(0),
+ gen: AtomicUsize::new(0),
+ }
+ }
+
+ pub fn wait(&self) {
+ let old_gen = self.gen.load(Ordering::Acquire);
+ let old_waiting = self.waiting.fetch_add(1, Ordering::Relaxed);
+ if old_waiting + 1 == self.num {
+ self.waiting.store(0, Ordering::Relaxed);
+ self.gen.fetch_add(1, Ordering::Release);
+ } else {
+ while old_gen == self.gen.load(Ordering::Acquire) {}
+ }
+ }
+}
--
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