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From: Thomas Gleixner <tglx@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>, Breno Leitao <leitao@debian.org>
Cc: "Ingo Molnar" <mingo@redhat.com>,
	"Darren Hart" <dvhart@infradead.org>,
	"Davidlohr Bueso" <dave@stgolabs.net>,
	"André Almeida" <andrealmeid@igalia.com>,
	linux-kernel@vger.kernel.org, puranjay@kernel.org,
	rmikey@meta.com, stuclar@meta.com, namhyung@kernel.org,
	kernel-team@meta.com
Subject: Re: [PATCH RFC] futex: avoid false sharing between hb->chain and the bucket lock
Date: Wed, 10 Jun 2026 13:22:34 +0200	[thread overview]
Message-ID: <87h5na3ait.ffs@fw13> (raw)
In-Reply-To: <20260609201809.GA1430057@noisy.programming.kicks-ass.net>

On Tue, Jun 09 2026 at 22:18, Peter Zijlstra wrote:
> On Tue, Jun 09, 2026 at 10:11:17PM +0200, Peter Zijlstra wrote:
>> Anyway, how does something like the below work for you? It's a total
>> hack job, but it (sorta) builds and runs.
>> 
>
> Please use this one, I spotted a silly bug.

So I ran this on two machines.

SKL dual socket 112 threads:

		Baseline	Patched

shared (16k)	1571857 	1641435         + 4.4%
autosize (512)	 646390 	 903371         +39.7%
-b 256		 464395 	 587014         +26.4%
-b 512		 715687 	 995943         +39.2%
-b 1024		 995085 	1396328         +40.3%
-b 2048		1293114         1668395         +29.0%
-b 4096		2124438 	2240228         + 5.5%

Zen3 dual socket 256 threads:

		Baseline	Patched

shared	(16k)	1275840		1381279	 	+ 8.2%
autosize (512)	1252745		1482179		+18.3%
-b 256		 856274		 955455		+11.5%
-b 512		1267490		1544010		+21.8%
-b 1024		1424013		1625424		+14.1%
-b 2048		1505181		1669342		+10.9%
-b 4096		1465993		1688932		+15.2%


  reply	other threads:[~2026-06-10 11:22 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-06-05 16:53 [PATCH RFC] futex: avoid false sharing between hb->chain and the bucket lock Breno Leitao
2026-06-09 10:46 ` Peter Zijlstra
2026-06-09 15:28   ` Breno Leitao
2026-06-09 20:11     ` Peter Zijlstra
2026-06-09 20:18       ` Peter Zijlstra
2026-06-10 11:22         ` Thomas Gleixner [this message]
2026-06-10 11:25           ` Peter Zijlstra
2026-06-10 13:55             ` Peter Zijlstra
2026-06-10 13:56             ` Breno Leitao
2026-06-09 20:16     ` Thomas Gleixner
2026-06-09 20:23       ` Peter Zijlstra
2026-06-09 20:25       ` Peter Zijlstra
2026-06-09 20:32         ` Thomas Gleixner

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