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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B496FC433F5 for ; Sat, 6 Nov 2021 19:09:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7F8D96108B for ; Sat, 6 Nov 2021 19:09:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234897AbhKFTMg (ORCPT ); Sat, 6 Nov 2021 15:12:36 -0400 Received: from mail.kernel.org ([198.145.29.99]:59474 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234125AbhKFTMd (ORCPT ); Sat, 6 Nov 2021 15:12:33 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 895BC6108D; Sat, 6 Nov 2021 19:09:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1636225792; bh=/hyIP0/aSOelHVPVtktQKqkIJLZLCwG1oOqZzq2GOi0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=HKwfgIdXifT8pDUrWDFph8Ug8hHvg476fdxt+wUYCjTHc0TsvEixX26ArWJr1faYK /PUv5K5puB5uzap7QXKHdcldroT8bjTSnL3NRHOGoDJAn4xhG7sfJq5lO57rg8jQAI Q49dlUdL4zSlNtEU7TbdIQJiNqKm9H3yLcnNLiZeiHtRXeINBGq44id6KFd9uQQmX7 BR5HCIcjA+68wFhRzTk9qDehaLdZTcUYf16Oa3ho55gulLjTRXetpE5wyZLzlEo41T 1Rmw0OeVERNfRJenOVTTycpuXv4AgurG0AXrHDvLjtQneDS6UfhEbvNL5XZJ1F5H93 Gx0yrW4qXmHrA== Received: by quaco.ghostprotocols.net (Postfix, from userid 1000) id 17B94410A1; Sat, 6 Nov 2021 16:09:49 -0300 (-03) Date: Sat, 6 Nov 2021 16:09:49 -0300 From: Arnaldo Carvalho de Melo To: Namhyung Kim Cc: Jiri Olsa , Ingo Molnar , Peter Zijlstra , LKML , Andi Kleen , Ian Rogers , Stephane Eranian , Ravi Bangoria Subject: Re: [PATCH v4] perf evsel: Fix missing exclude_{host,guest} setting Message-ID: References: <20211105205847.120950-1-namhyung@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20211105205847.120950-1-namhyung@kernel.org> X-Url: http://acmel.wordpress.com Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Em Fri, Nov 05, 2021 at 01:58:47PM -0700, Namhyung Kim escreveu: > The current logic for the perf missing feature has a bug that it can > wrongly clear some modifiers like G or H. Actually some PMUs don't > support any filtering or exclusion while others do. But we check it > as a global feature. > > For example, the cycles event can have 'G' modifier to enable it only > in the guest mode on x86. When you don't run any VMs it'll return 0. > > # perf stat -a -e cycles:G sleep 1 > > Performance counter stats for 'system wide': > > 0 cycles:G > > 1.000721670 seconds time elapsed > > But when it's used with other pmu events that don't support G modifier, > it'll be reset and return non-zero values. > > # perf stat -a -e cycles:G,msr/tsc/ sleep 1 > > Performance counter stats for 'system wide': > > 538,029,960 cycles:G > 16,924,010,738 msr/tsc/ > > 1.001815327 seconds time elapsed > > This is because of the missing feature detection logic being global. > Add a hashmap to set pmu-specific exclude_host/guest features. ⬢[acme@toolbox perf]$ perf test python 19: 'import perf' in python : FAILED! ⬢[acme@toolbox perf]$ perf test -v python Couldn't bump rlimit(MEMLOCK), failures may take place when creating BPF maps, etc 19: 'import perf' in python : --- start --- test child forked, pid 11602 python usage test: "echo "import sys ; sys.path.append('/tmp/build/perf/python'); import perf" | '/usr/bin/python3' " Traceback (most recent call last): File "", line 1, in ImportError: /tmp/build/perf/python/perf.cpython-39-x86_64-linux-gnu.so: undefined symbol: evsel__find_pmu test child finished with -1 ---- end ---- 'import perf' in python: FAILED! ⬢[acme@toolbox perf]$ Trying to fix this now. please do a 'perf test' before submitting patches. - Arnaldo > Reported-by: Stephane Eranian > Cc: Ravi Bangoria > Signed-off-by: Namhyung Kim > --- > v4 changes) > * add pmu->missing_features.exclude_guest > * bail out if evsel->exclude_GH is set > > v3 changes) > * check memory allocation failure > * add more NULL check > > v2 changes) > * change to enum perf_missing_pmu_features > * pass NULL to hashmap__find() to skip checking > * add a blank line after declaration > > tools/perf/util/evsel.c | 27 ++++++++++++++++++++++----- > tools/perf/util/evsel.h | 4 ++++ > tools/perf/util/pmu.h | 4 ++++ > 3 files changed, 30 insertions(+), 5 deletions(-) > > diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c > index 2cfc2935d1d2..3cc1f8fcf15c 100644 > --- a/tools/perf/util/evsel.c > +++ b/tools/perf/util/evsel.c > @@ -1824,7 +1824,7 @@ static void evsel__disable_missing_features(struct evsel *evsel) > evsel->open_flags &= ~(unsigned long)PERF_FLAG_FD_CLOEXEC; > if (perf_missing_features.mmap2) > evsel->core.attr.mmap2 = 0; > - if (perf_missing_features.exclude_guest) > + if (evsel->pmu && evsel->pmu->missing_features.exclude_guest) > evsel->core.attr.exclude_guest = evsel->core.attr.exclude_host = 0; > if (perf_missing_features.lbr_flags) > evsel->core.attr.branch_sample_type &= ~(PERF_SAMPLE_BRANCH_NO_FLAGS | > @@ -1917,10 +1917,27 @@ bool evsel__detect_missing_features(struct evsel *evsel) > perf_missing_features.mmap2 = true; > pr_debug2_peo("switching off mmap2\n"); > return true; > - } else if (!perf_missing_features.exclude_guest && > - (evsel->core.attr.exclude_guest || evsel->core.attr.exclude_host)) { > - perf_missing_features.exclude_guest = true; > - pr_debug2_peo("switching off exclude_guest, exclude_host\n"); > + } else if ((evsel->core.attr.exclude_guest || evsel->core.attr.exclude_host) && > + (evsel->pmu == NULL || evsel->pmu->missing_features.exclude_guest)) { > + if (evsel->pmu == NULL) { > + evsel->pmu = evsel__find_pmu(evsel); > + if (evsel->pmu) > + evsel->pmu->missing_features.exclude_guest = true; > + else { > + /* we cannot find PMU, disable attrs now */ > + evsel->core.attr.exclude_host = false; > + evsel->core.attr.exclude_guest = false; > + } > + } > + > + if (evsel->exclude_GH) { > + pr_debug2_peo("PMU has no exclude_host/guest support, bailing out\n"); > + return false; > + } > + if (!perf_missing_features.exclude_guest) { > + perf_missing_features.exclude_guest = true; > + pr_debug2_peo("switching off exclude_guest, exclude_host\n"); > + } > return true; > } else if (!perf_missing_features.sample_id_all) { > perf_missing_features.sample_id_all = true; > diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h > index 846c827934de..dcc87c2881b8 100644 > --- a/tools/perf/util/evsel.h > +++ b/tools/perf/util/evsel.h > @@ -22,6 +22,7 @@ struct target; > struct hashmap; > struct bperf_leader_bpf; > struct bperf_follower_bpf; > +struct perf_pmu; > > typedef int (evsel__sb_cb_t)(union perf_event *event, void *data); > > @@ -153,6 +154,9 @@ struct evsel { > }; > unsigned long open_flags; > int precise_ip_original; > + > + /* for missing_features */ > + struct perf_pmu *pmu; > }; > > struct perf_missing_features { > diff --git a/tools/perf/util/pmu.h b/tools/perf/util/pmu.h > index 15bbec3a9959..541889fa9f9c 100644 > --- a/tools/perf/util/pmu.h > +++ b/tools/perf/util/pmu.h > @@ -49,6 +49,10 @@ struct perf_pmu { > struct list_head caps; /* HEAD struct perf_pmu_caps -> list */ > struct list_head list; /* ELEM */ > struct list_head hybrid_list; > + > + struct { > + bool exclude_guest; > + } missing_features; > }; > > extern struct perf_pmu perf_pmu__fake; > -- > 2.34.0.rc0.344.g81b53c2807-goog -- - Arnaldo