From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 7ED6AEB64DD for ; Thu, 13 Jul 2023 09:16:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:From:References:Cc:To: Subject:MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=vrdgZ+Ok+joC1Vev1fjTVYXV9YhgwL4ngLGtuwA6ats=; b=v8U4iucQ/cQhEw bosQ6KilbFwaI8JLkygx5VDM+/lhv2u2E+ywQaRc+AH3kHGLsDk/oEpUU/S/gGlZCIVt6SvxrremD AwFNm66XI5rDcLxVhOukBQQ7LiOls6ltN5pOsbWMr4RybfQvS1haCbOUX/HUYeKTA02gxGotn0GQD LeUl8Ipr0EHRaV3U9n1mNug0dTPIzEeEl91OZZA3OBEHMGU+I2OLEQjm0La8+ScQ0T4fdI4z1uGAz rAOT7dQD1vAb+HWUkF4oLwHQpieDCE0BUSn06Z3ueoEDelWuY+gd5Hqda2jdl48ITWOS5NtVPe8ai X7oMZUMCo9DWzbk6xebg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qJsQU-002afb-1L; Thu, 13 Jul 2023 09:15:54 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qJsQR-002ae5-03 for linux-arm-kernel@lists.infradead.org; Thu, 13 Jul 2023 09:15:52 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id B50E51570; Thu, 13 Jul 2023 02:16:29 -0700 (PDT) Received: from [192.168.1.3] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id D24F63F740; Thu, 13 Jul 2023 02:15:44 -0700 (PDT) Message-ID: <12a2da14-1fd0-09cd-92c0-c43dd1df51eb@arm.com> Date: Thu, 13 Jul 2023 10:15:33 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.9.0 Subject: Re: [PATCH 4/4] perf: Remove unused PERF_PMU_CAP_HETEROGENEOUS_CPUS capability To: Anshuman Khandual Cc: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Adrian Hunter , Thomas Gleixner , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Will Deacon , Kan Liang , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-perf-users@vger.kernel.org, irogers@google.com References: <20230710122138.1450930-1-james.clark@arm.com> <20230710122138.1450930-5-james.clark@arm.com> <96a3d12a-71d8-1779-28a3-316e1838292e@arm.com> <6143e1cd-4db7-d980-a189-b9b06f99d7c4@arm.com> Content-Language: en-US From: James Clark In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230713_021551_147149_65B33019 X-CRM114-Status: GOOD ( 23.29 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 13/07/2023 08:30, Anshuman Khandual wrote: > > > On 7/11/23 19:45, James Clark wrote: >> >> >> On 11/07/2023 13:10, Anshuman Khandual wrote: >>> >>> >>> On 7/10/23 17:51, James Clark wrote: >>>> Since commit bd2756811766 ("perf: Rewrite core context handling") the >>>> relationship between perf_event_context and PMUs has changed so that >>>> the error scenario that PERF_PMU_CAP_HETEROGENEOUS_CPUS originally >>>> silenced no longer exists. >>>> >>>> Remove the capability to avoid confusion that it actually influences >>>> any perf core behavior. This change should be a no-op. >>>> >>>> Signed-off-by: James Clark >>>> --- >>>> include/linux/perf_event.h | 2 +- >>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>> >>>> diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h >>>> index d5628a7b5eaa..3f4d941fd6c5 100644 >>>> --- a/include/linux/perf_event.h >>>> +++ b/include/linux/perf_event.h >>>> @@ -288,7 +288,7 @@ struct perf_event_pmu_context; >>>> #define PERF_PMU_CAP_EXTENDED_REGS 0x0008 >>>> #define PERF_PMU_CAP_EXCLUSIVE 0x0010 >>>> #define PERF_PMU_CAP_ITRACE 0x0020 >>>> -#define PERF_PMU_CAP_HETEROGENEOUS_CPUS 0x0040 >>>> +/* Unused 0x0040 */ >>> >>> Small nit, "Unused" marking might not be required here. >>> >> >> But then it would be very easy to miss that there is a free bit if I >> don't leave the comment. Is it really better without it? >> >> I could shift all the following ones down by one bit, but it would be a > > Sounds as a better option IMHO. > >> lot of work to make sure that nobody has hard coded some check for one >> of the bits instead of using the define somewhere. > > These are not user visible ABI and hence defined in include/linux/perf_event.h > to be used by drivers registering a PMU for capability enumeration. I am just > wondering why they might have been hard coded any where ? > You never know, I've seen worse! I suppose we'll find out if I change it and anything breaks. It will probably be fine though, I'll make the change on the next version. >> >>>> #define PERF_PMU_CAP_NO_EXCLUDE 0x0080 >>>> #define PERF_PMU_CAP_AUX_OUTPUT 0x0100 >>>> #define PERF_PMU_CAP_EXTENDED_HW_TYPE 0x0200 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel