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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 135D6C433EF for ; Wed, 16 Feb 2022 14:18:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234856AbiBPOSP (ORCPT ); Wed, 16 Feb 2022 09:18:15 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:33044 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234116AbiBPOSL (ORCPT ); Wed, 16 Feb 2022 09:18:11 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9EFDE1B4453 for ; Wed, 16 Feb 2022 06:17:58 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 55DBBB81EDA for ; Wed, 16 Feb 2022 14:17:57 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D259DC004E1; Wed, 16 Feb 2022 14:17:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1645021076; bh=25WzSdKtFWUOysZRmxAVLJb+CZcoj//JQjD1ChtvlNM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=JyFpMMkNVLu4oQG+tcrjlS2O0c2RGmmc4jAVRHRX5cJ49S+5KlwgUSg/lLw9i9VBR HUZ19T20xf6Gz9tIkghUYrISocVbfAc6avwO0iW0IIn4woxVv4fpB7TgnBqQpg9Ql/ rN6ipK0H5Ho69WPqVD5vCUqiimT4J0ro7y2Q1TsXIeU41wgXMMuuBoS4bpc07BxAWU s5YS8X4pctUsVoUtjTSNf1zk4HsIKuKq9AzpvPzsuyX4LJ/qmJqLZfVNpZO1iYhjUU M8GhgX/WjCrk8RGG85ZrpIoEx5yTfznHJYwK0ImDp4VfYbmmPCFx8SFAnOZgj2YWZv +FRa8oCRY6MZw== Received: by quaco.ghostprotocols.net (Postfix, from userid 1000) id B4732400FE; Wed, 16 Feb 2022 11:17:53 -0300 (-03) Date: Wed, 16 Feb 2022 11:17:53 -0300 From: Arnaldo Carvalho de Melo To: Stephane Eranian Cc: linux-kernel@vger.kernel.org, peterz@infradead.org, kim.phillips@amd.com, acme@redhat.com, jolsa@redhat.com, songliubraving@fb.com Subject: Re: [PATCH v6 11/12] perf tools: Improve error handling of AMD Branch Sampling Message-ID: References: <20220208211637.2221872-1-eranian@google.com> <20220208211637.2221872-12-eranian@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20220208211637.2221872-12-eranian@google.com> X-Url: http://acmel.wordpress.com Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Em Tue, Feb 08, 2022 at 01:16:36PM -0800, Stephane Eranian escreveu: > Improve the error message printed by perf when perf_event_open() fails on > AMD Zen3 when using the branch sampling feature. In the case of EINVAL, there > are two main reasons: frequency mode or period is smaller than the depth of > the branch sampling buffer (16). The patch checks the parameters of the call > and tries to print a relevant message to explain the error: > > $ perf record -b -e cpu/branch-brs/ -c 10 ls > Error: > AMD Branch Sampling does not support sampling period smaller than what is reported in /sys/devices/cpu/caps/branches. > > $ perf record -b -e cpu/branch-brs/ ls > Error: > AMD Branch Sampling does not support frequency mode sampling, must pass a fixed sampling period via -c option or cpu/branch-brs,period=xxxx/. > > Signed-off-by: Stephane Eranian > [Rebased on commit 9fe8895a27a84 ("perf env: Add perf_env__cpuid, perf_env__{nr_}pmu_mappings")] > Signed-off-by: Kim Phillips > --- > tools/perf/util/evsel.c | 14 ++++++++++++++ > 1 file changed, 14 insertions(+) > > diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c > index d42f63a484df..7311e7b4d34d 100644 > --- a/tools/perf/util/evsel.c > +++ b/tools/perf/util/evsel.c > @@ -2857,6 +2857,12 @@ static bool is_amd_ibs(struct evsel *evsel) > return evsel->core.attr.precise_ip || !strncmp(evsel->pmu_name, "ibs", 3); > } > > +static bool is_amd_brs(struct evsel *evsel) > +{ > + return ((evsel->core.attr.config & 0xff) == 0xc4) && > + (evsel->core.attr.sample_type & PERF_SAMPLE_BRANCH_STACK); > +} > + Well, this assumes we're on x86_64, right? Shouldn't we have some extra condition using perf_env routines to check we're on x86_64. Did a quick check and powerpc also supports PERF_SAMPLE_BRANCH_STACK ⬢[acme@toolbox perf]$ find arch/ -name "*.c" | xargs grep PERF_SAMPLE_BRANCH_STACK arch/powerpc/perf/core-book3s.c: if (event->attr.sample_type & PERF_SAMPLE_BRANCH_STACK) { arch/x86/events/intel/ds.c: if (sample_type & PERF_SAMPLE_BRANCH_STACK) { arch/x86/events/intel/ds.c: PERF_SAMPLE_BRANCH_STACK | arch/x86/events/intel/lbr.c: * in PERF_SAMPLE_BRANCH_STACK sample may vary. arch/x86/kvm/vmx/pmu_intel.c: * - set 'sample_type = PERF_SAMPLE_BRANCH_STACK' and arch/x86/kvm/vmx/pmu_intel.c: .sample_type = PERF_SAMPLE_BRANCH_STACK, ⬢[acme@toolbox perf]$ arch/powerpc/perf/core-book3s.c: if (event->attr.sample_type & PERF_SAMPLE_BRANCH_STACK) { struct cpu_hw_events *cpuhw; cpuhw = this_cpu_ptr(&cpu_hw_events); power_pmu_bhrb_read(event, cpuhw); data.br_stack = &cpuhw->bhrb_stack; } > int evsel__open_strerror(struct evsel *evsel, struct target *target, > int err, char *msg, size_t size) > { > @@ -2971,6 +2977,14 @@ int evsel__open_strerror(struct evsel *evsel, struct target *target, > return scnprintf(msg, size, > "AMD IBS may only be available in system-wide/per-cpu mode. Try using -a, or -C and workload affinity"); > } > + if (is_amd_brs(evsel)) { > + if (evsel->core.attr.freq) > + return scnprintf(msg, size, > + "AMD Branch Sampling does not support frequency mode sampling, must pass a fixed sampling period via -c option or cpu/branch-brs,period=xxxx/."); > + /* another reason is that the period is too small */ > + return scnprintf(msg, size, > + "AMD Branch Sampling does not support sampling period smaller than what is reported in /sys/devices/cpu/caps/branches."); > + } > } > > break; > -- > 2.35.0.263.gb82422642f-goog -- - Arnaldo