Attachment 243029 Details for Bug 272238 – Patch to reduce false sharing with pthreads rw and spin locks

[patch] Patch to reduce false sharing with pthreads rw and spin locks

libthr-false-sharing.patch (text/plain), 1.77 KB, created by Greg Becker on 2023-06-27 01:26:59 UTC

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Creator: Greg Becker

Created: 2023-06-27 01:26:59 UTC

Size: 1.77 KB

patch

obsolete

>From 150a2d68c91847bc80eb3d38a19a76dc48520e4d Mon Sep 17 00:00:00 2001
>From: Greg Becker <becker.greg@att.net>
>Date: Mon, 26 Jun 2023 20:08:29 -0500
>Subject: =?UTF-8?q?Round=20up=20allocations=20of=20pthread=5Frwlock=20and?=
> =?UTF-8?q?=20pthread=5Fspinlock=20to=20CACHE=5FLINE=5FSIZE=0Ato=20reduce?=
> =?UTF-8?q?=20severe=20performance=20degradation=20due=20to=20false-sharin?=
> =?UTF-8?q?g.=20=20Note=20that=20this=0Adoes=20not=20account=20for=20hardw?=
> =?UTF-8?q?are=20which=20can=20perform=20adjacent=20cacheline=20prefetch.?=
>
>---
> lib/libthr/thread/thr_pspinlock.c | 2 +-
> lib/libthr/thread/thr_rwlock.c    | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
>diff --git a/lib/libthr/thread/thr_pspinlock.c b/lib/libthr/thread/thr_pspinlock.c
>index 089416a18a07..22016efb6211 100644
>--- a/lib/libthr/thread/thr_pspinlock.c
>+++ b/lib/libthr/thread/thr_pspinlock.c
>@@ -60,7 +60,7 @@ _pthread_spin_init(pthread_spinlock_t *lock, int pshared)
> 	if (lock == NULL)
> 		return (EINVAL);
> 	if (pshared == PTHREAD_PROCESS_PRIVATE) {
>-		lck = malloc(sizeof(struct pthread_spinlock));
>+		lck = malloc(roundup(sizeof(struct pthread_spinlock), CACHE_LINE_SIZE));
> 		if (lck == NULL)
> 			return (ENOMEM);
> 		*lock = lck;
>diff --git a/lib/libthr/thread/thr_rwlock.c b/lib/libthr/thread/thr_rwlock.c
>index b7526376a9a3..0f66398989a4 100644
>--- a/lib/libthr/thread/thr_rwlock.c
>+++ b/lib/libthr/thread/thr_rwlock.c
>@@ -102,7 +102,7 @@ rwlock_init(pthread_rwlock_t *rwlock, const pthread_rwlockattr_t *attr)
> 
> 	if (attr == NULL || *attr == NULL ||
> 	    (*attr)->pshared == PTHREAD_PROCESS_PRIVATE) {
>-		prwlock = calloc(1, sizeof(struct pthread_rwlock));
>+		prwlock = calloc(1, roundup(sizeof(struct pthread_rwlock), CACHE_LINE_SIZE));
> 		if (prwlock == NULL)
> 			return (ENOMEM);
> 		*rwlock = prwlock;
>-- 
>2.40.1
>

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Attachments on bug 272238: 243025 | 243029