From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753263AbeCEWCQ (ORCPT ); Mon, 5 Mar 2018 17:02:16 -0500 Received: from smtp.codeaurora.org ([198.145.29.96]:45250 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753032AbeCEWCO (ORCPT ); Mon, 5 Mar 2018 17:02:14 -0500 DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org CDBF8601A1 Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=skannan@codeaurora.org Message-ID: <5A9DBE64.3060209@codeaurora.org> Date: Mon, 05 Mar 2018 14:02:12 -0800 From: Saravana Kannan User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130329 Thunderbird/17.0.5 MIME-Version: 1.0 To: Mark Rutland CC: suzuki.poulose@arm.com, Peter Zijlstra , rananta@codeaurora.org, Arnaldo Carvalho de Melo , linux-kernel@vger.kernel.org, Alexander Shishkin , Ingo Molnar , Namhyung Kim , avilaj@codeaurora.org, Jiri Olsa , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v2] perf/core: Add support for PMUs that can be read from more than 1 CPU References: <1520039693-30914-1-git-send-email-skannan@codeaurora.org> <20180305121702.l64rzrckog6d7jop@lakrids.cambridge.arm.com> <20180305122140.wwwu4hvhssouuzcp@lakrids.cambridge.arm.com> In-Reply-To: <20180305122140.wwwu4hvhssouuzcp@lakrids.cambridge.arm.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/05/2018 04:21 AM, Mark Rutland wrote: > On Mon, Mar 05, 2018 at 12:17:02PM +0000, Mark Rutland wrote: >> On Fri, Mar 02, 2018 at 05:14:53PM -0800, Saravana Kannan wrote: > >>> @@ -629,6 +629,7 @@ struct perf_event { >>> >>> int oncpu; >>> int cpu; >>> + cpumask_t readable_on_cpus; >> >> For most PMUs, this will be emptry, and it's potentially *very* large >> (e.g. on systems where NR_CPUS is 4096). Please use a poitner to a mask, >> as I suggested in [1], e.g. > >> [1] https://lkml.kernel.org/r/20171128124534.3jvuala525wvn64r@wfg-t540p.sh.intel.com > > Whoops, that should've been: > > [1] https://lkml.kernel.org/r/20180225143802.denbkubqjg2dc7af@salmiak > I didn't notice you mentioned the use of pointers, but I was planning on doing that anyway. But then I realize people will complain about cacheline bouncing across 4096 CPUs if I use a cpu mask pointer. Thanks, Saravana -- Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project