From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S941161AbcJXSxd (ORCPT ); Mon, 24 Oct 2016 14:53:33 -0400 Received: from mail.kernel.org ([198.145.29.136]:33972 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934802AbcJXSx1 (ORCPT ); Mon, 24 Oct 2016 14:53:27 -0400 Date: Mon, 24 Oct 2016 15:53:21 -0300 From: Arnaldo Carvalho de Melo To: Davidlohr Bueso Cc: Ingo Molnar , linux-kernel@vger.kernel.org, Sebastian Andrzej Siewior , Peter Zijlstra , Arnaldo Carvalho de Melo Subject: Re: [PATCH 33/37] perf bench futex: Cache align the worker struct Message-ID: <20161024185321.GC5136@kernel.org> References: <1477326057-24080-1-git-send-email-acme@kernel.org> <1477326057-24080-34-git-send-email-acme@kernel.org> <94c3f945b1f11c799d4ec4ab5a0efc90@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <94c3f945b1f11c799d4ec4ab5a0efc90@suse.de> X-Url: http://acmel.wordpress.com User-Agent: Mutt/1.7.0 (2016-08-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Em Mon, Oct 24, 2016 at 11:50:50AM -0700, Davidlohr Bueso escreveu: > On 2016-10-24 09:20, Arnaldo Carvalho de Melo wrote: > > From: Sebastian Andrzej Siewior > > > > It popped up in perf testing that the worker consumes some amount of > > CPU. It boils down to the increment of `ops` which causes cache line > > bouncing between the individual threads. > > > > This patch aligns the struct by 256 bytes to ensure that not a cache > > line is shared among CPUs. 128 byte is the x86 worst case and grep says > > that L1_CACHE_SHIFT is set to 8 on s390. > > Hmm so this one should have been replaced with this: > > https://marc.info/?l=linux-kernel&m=147690008801082 Humm, sorry, can you please send a patch fixing this? - Arnaldo