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 X-Spam-Level: X-Spam-Status: No, score=-13.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 10B82C43603 for ; Wed, 11 Dec 2019 14:46:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D7850208C3 for ; Wed, 11 Dec 2019 14:46:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729327AbfLKOqs (ORCPT ); Wed, 11 Dec 2019 09:46:48 -0500 Received: from foss.arm.com ([217.140.110.172]:60634 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727457AbfLKOqs (ORCPT ); Wed, 11 Dec 2019 09:46:48 -0500 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 592621FB; Wed, 11 Dec 2019 06:46:47 -0800 (PST) Received: from lakrids.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id C72223F67D; Wed, 11 Dec 2019 06:46:45 -0800 (PST) Date: Wed, 11 Dec 2019 14:46:43 +0000 From: Mark Rutland To: Arnaldo Carvalho de Melo Cc: John Garry , Jiri Olsa , Peter Zijlstra , Ingo Molnar , Alexander Shishkin , Namhyung Kim , will@kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Linuxarm , linux-perf-users@vger.kernel.org Subject: Re: [PATCHES] Fix 'perf top' breakage on architectures not providing get_cpuid() Re: perf top for arm64? Message-ID: <20191211144643.GC35097@lakrids.cambridge.arm.com> References: <1573045254-39833-1-git-send-email-john.garry@huawei.com> <20191106140036.GA6259@kernel.org> <418023e7-a50d-cb6f-989f-2e6d114ce5d8@huawei.com> <20191210163655.GG14123@krava> <952dc484-2739-ee65-f41c-f0198850ab10@huawei.com> <20191210170841.GA23357@krava> <9a31536b-f266-e305-1107-2f745d0a33e3@huawei.com> <20191210195113.GD13965@kernel.org> <20191211133319.GA15181@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191211133319.GA15181@kernel.org> User-Agent: Mutt/1.11.1+11 (2f07cb52) (2018-12-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Dec 11, 2019 at 10:33:19AM -0300, Arnaldo Carvalho de Melo wrote: > So can you take a look at the two patches below and provide me Acked-by > and/or Reviewed-by and/or Tested-by? I just gave this a spin. With vanilla v5.5-rc1 perf top behaves as John reported, and with these applied atop perf works as expected: Tested-by: Mark Rutland >From scaning the code, the only other user of get_cpuid() that ends up giving up is perf kvm, but AFAICT that never supported arm64, so that looks sound to me: Reviewed-by: Mark Rutland Thanks, Mark. > From 53c6cde6a71a1a9283763bd2e938b229b50c2cd5 Mon Sep 17 00:00:00 2001 > From: Arnaldo Carvalho de Melo > Date: Wed, 11 Dec 2019 10:09:24 -0300 > Subject: [PATCH 1/2] perf arch: Make the default get_cpuid() return compatible > error > > Some of the functions calling get_cpuid() propagate back the error it > returns, and all are using errno (positive) values, make the weak > default get_cpuid() function return ENOSYS to be consistent and to allow > checking if this is an arch not providing this function or if a provided > one is having trouble getting the cpuid, to decide if the warning should > be provided to the user or just a debug message should be emitted. > > Cc: Adrian Hunter > Cc: Jiri Olsa > Cc: John Garry > Cc: Mark Rutland > Cc: Namhyung Kim > Cc: Will Deacon > Link: https://lkml.kernel.org/n/tip-lxwjr0cd2eggzx04a780ffrv@git.kernel.org > Signed-off-by: Arnaldo Carvalho de Melo > --- > tools/perf/util/header.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c > index becc2d109423..4d39a75551a0 100644 > --- a/tools/perf/util/header.c > +++ b/tools/perf/util/header.c > @@ -850,7 +850,7 @@ int __weak strcmp_cpuid_str(const char *mapcpuid, const char *cpuid) > */ > int __weak get_cpuid(char *buffer __maybe_unused, size_t sz __maybe_unused) > { > - return -1; > + return ENOSYS; /* Not implemented */ > } > > static int write_cpuid(struct feat_fd *ff, > -- > 2.21.0 > > From c6c6a3e2eb6982e37294abcac389effd298cf730 Mon Sep 17 00:00:00 2001 > From: Arnaldo Carvalho de Melo > Date: Wed, 11 Dec 2019 10:21:59 -0300 > Subject: [PATCH 2/2] perf top: Do not bail out when perf_env__read_cpuid() > returns ENOSYS > > 'perf top' stopped working on hw architectures that do not provide a > get_cpuid() implementation and thus fallback to the weak get_cpuid() > default function. > > This is done because at annotation time we may need it in the arch > specific annotation init routine, but that is only being used by arches > that do provide a get_cpuid() implementation: > > $ find tools/ -name "*.[ch]" | xargs grep 'evlist->env' > tools/perf/builtin-top.c: top.evlist->env = &perf_env; > tools/perf/util/evsel.c: return evsel->evlist->env; > tools/perf/util/s390-cpumsf.c: sf->machine_type = s390_cpumsf_get_type(session->evlist->env->cpuid); > tools/perf/util/header.c: session->evlist->env = &header->env; > tools/perf/util/sample-raw.c: const char *arch_pf = perf_env__arch(evlist->env); > $ > > $ find tools/perf/arch -name "*.[ch]" | xargs grep -w get_cpuid > tools/perf/arch/x86/util/auxtrace.c: ret = get_cpuid(buffer, sizeof(buffer)); > tools/perf/arch/x86/util/header.c:get_cpuid(char *buffer, size_t sz) > tools/perf/arch/powerpc/util/header.c:get_cpuid(char *buffer, size_t sz) > tools/perf/arch/s390/util/header.c: * Implementation of get_cpuid(). > tools/perf/arch/s390/util/header.c:int get_cpuid(char *buffer, size_t sz) > tools/perf/arch/s390/util/header.c: if (buf && get_cpuid(buf, 128)) > $ > > For 'report' or 'script', i.e. tools working on perf.data files, that is > setup while reading the header, its just top that needs to explicitely > read it at tool start. > > Reported-by: John Garry > Analysed-by: Jiri Olsa > Cc: Adrian Hunter > Cc: Mark Rutland > Cc: Namhyung Kim > Cc: Will Deacon > Link: https://lkml.kernel.org/n/tip-lxwjr0cd2eggzx04a780ffrv@git.kernel.org > Signed-off-by: Arnaldo Carvalho de Melo > --- > tools/perf/builtin-top.c | 10 +++++++--- > 1 file changed, 7 insertions(+), 3 deletions(-) > > diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c > index dc80044bc46f..795e353de095 100644 > --- a/tools/perf/builtin-top.c > +++ b/tools/perf/builtin-top.c > @@ -1568,9 +1568,13 @@ int cmd_top(int argc, const char **argv) > */ > status = perf_env__read_cpuid(&perf_env); > if (status) { > - pr_err("Couldn't read the cpuid for this machine: %s\n", > - str_error_r(errno, errbuf, sizeof(errbuf))); > - goto out_delete_evlist; > + /* > + * Some arches do not provide a get_cpuid(), so just use pr_debug, otherwise > + * warn the user explicitely. > + */ > + eprintf(status == ENOSYS ? 1 : 0, verbose, > + "Couldn't read the cpuid for this machine: %s\n", > + str_error_r(errno, errbuf, sizeof(errbuf))); > } > top.evlist->env = &perf_env; > > -- > 2.21.0 >