From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751987AbdJBQtk (ORCPT ); Mon, 2 Oct 2017 12:49:40 -0400 Received: from mx1.redhat.com ([209.132.183.28]:58114 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751127AbdJBQti (ORCPT ); Mon, 2 Oct 2017 12:49:38 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 95077C04AC64 Authentication-Results: ext-mx07.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx07.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=acme@redhat.com Date: Mon, 2 Oct 2017 13:49:30 -0300 From: Arnaldo Carvalho de Melo To: Will Deacon Cc: Kim Phillips , linux-arm-kernel@lists.infradead.org, marc.zyngier@arm.com, mark.rutland@arm.com, tglx@linutronix.de, peterz@infradead.org, alexander.shishkin@linux.intel.com, robh@kernel.org, suzuki.poulose@arm.com, pawel.moll@arm.com, mathieu.poirier@linaro.org, mingo@redhat.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH v5 6/7] drivers/perf: Add support for ARMv8.2 Statistical Profiling Extension Message-ID: <20171002164930.GB2121@redhat.com> References: <1506607791-8621-1-git-send-email-will.deacon@arm.com> <1506607791-8621-7-git-send-email-will.deacon@arm.com> <20170929171940.2aa33d00463b1e9c987aea15@arm.com> <20171002141405.GC12847@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20171002141405.GC12847@arm.com> X-Url: http://acmel.wordpress.com User-Agent: Mutt/1.5.20 (2009-12-10) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Mon, 02 Oct 2017 16:49:38 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Em Mon, Oct 02, 2017 at 03:14:05PM +0100, Will Deacon escreveu: > On Fri, Sep 29, 2017 at 05:19:40PM -0500, Kim Phillips wrote: > > On Thu, 28 Sep 2017 15:09:50 +0100 > > Will Deacon wrote: > > > + if (arm_spe_event_to_pmsevfr(event) & SYS_PMSEVFR_EL1_RES0) > > > + return -EOPNOTSUPP; > > > + if (attr->exclude_idle) > > > + return -EOPNOTSUPP; > > "PMU Hardware doesn't support sampling/overflow-interrupts." will be > > printed if the user didn't specify a sample period. Otherwise, a > > string with "/bin/dmesg may provide additional information." will be > > printed. > > I was hoping for a response from acme by now for this: > > https://www.spinics.net/lists/linux-perf-users/msg04066.html > > Alas, nothing. Looking at the #ifdef x86 in evsel.c, I'm guessing > > it'll be ok, although I'm still not sure how PMU-specific we can get in > > evsel.c, nor whether it's ok to communicate lists of h/w supported > > sample periods through /sys/bus/event_source/devices/... > > > > acme? OK to refactor evsel messaging for Arm, including parsing for > > which PMUs are being used, so customize the message? > > Arnaldo's probably got enough on his plate maintaining perf tool, so my > advice would be to post a patch as an RFC and use that as a concrete basis > for discussion. It often works out better starting with code, even if none > of it ends up getting merged (and you can include bits of your email above > in the cover letter). I'm all for more informative messages, and if you guys agree on how to provide the info in a way that combined with logic in evsel.c, I'd say do what Will suggested, post a patch series and include usage examples, before and after. - Arnaldo