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 85F69C433EF for ; Tue, 2 Nov 2021 14:10:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 64816610CC for ; Tue, 2 Nov 2021 14:10:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231247AbhKBOM5 (ORCPT ); Tue, 2 Nov 2021 10:12:57 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:55930 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230208AbhKBOMz (ORCPT ); Tue, 2 Nov 2021 10:12:55 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1635862220; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=86ZdZUm6BVWafF2DKgMsTetmERlgP6t1RGR51JEaCCI=; b=OGcft0uNClkPjQSD96l383qi51MLX+q4oj/IW2ehN0qN/7ZKXe334h1bx2NK+Z/ZjT5YAY piRWXFfzPT86ssGLGEks08qUQwpEWxmaaN0R1GcqoWF41mg2rcIoW8QRzJ04LV5t5DYt46 XobZQKtuBy909FX5DLUYZo41JuuiHzA= Received: from mail-ed1-f69.google.com (mail-ed1-f69.google.com [209.85.208.69]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-218-6kOk1-uuNEinKpmn3WLpBQ-1; Tue, 02 Nov 2021 10:10:19 -0400 X-MC-Unique: 6kOk1-uuNEinKpmn3WLpBQ-1 Received: by mail-ed1-f69.google.com with SMTP id y12-20020a056402270c00b003e28de6e995so5469061edd.11 for ; Tue, 02 Nov 2021 07:10:19 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=86ZdZUm6BVWafF2DKgMsTetmERlgP6t1RGR51JEaCCI=; b=20gKKQPZyKeqd6zTR56xIOxw1mOCgoO1Os1TUzcbXshT0jwHgg1GLsOcd8S7IN0Gk4 ZhuEgRugZpQykFY1KJJEK0xihwAWdRRZxFKxJwNFg3EpdEOvbeKQdNEmyq1HG5n6gI/E Gj3CfPQsoVoeMdgLCjaIljJxtg1Dm3Y95LLTsX7nCfsQ5YpLiA9Qe0Sb9tw1ZxwtBn3V NRjtZ96QFSf4Z4OIS51rIFmNVXuloSE+ObgpG5Y07N7bpw3+DxcVHF0ORcGIPlhf1l8P DxFqG79vYw3hHHcfm8N62XXtKP4bUi9oIOgxeCwTUCH9vuC36JlIVQ5FO4FCZQtCy410 ElQg== X-Gm-Message-State: AOAM531Di1CKiFMq6z3/ru+LjWLAUmClytUnoiyvKlifuCNYSCAAsL1J ohUgpO4bFbpPXbIRF2U8IPInqC+2p+Y1hGstc+t0OVQg7XPd2iClwqP6RhVGFK80nL+rJ1WS3qv yVhIVSUHBxR7yI7wkoD0kA3PO X-Received: by 2002:a05:6402:141:: with SMTP id s1mr51523202edu.317.1635862217881; Tue, 02 Nov 2021 07:10:17 -0700 (PDT) X-Google-Smtp-Source: ABdhPJwgSMWvUdqe4Amb7cVh+0lScwAX1oJJ5cj2yDtbS70L1GrVy4vaz/gplSKoY0UFXPb/4MaPAQ== X-Received: by 2002:a05:6402:141:: with SMTP id s1mr51523182edu.317.1635862217616; Tue, 02 Nov 2021 07:10:17 -0700 (PDT) Received: from krava ([83.240.63.48]) by smtp.gmail.com with ESMTPSA id h17sm5081574ede.38.2021.11.02.07.10.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 02 Nov 2021 07:10:17 -0700 (PDT) Date: Tue, 2 Nov 2021 15:10:15 +0100 From: Jiri Olsa To: Namhyung Kim Cc: Arnaldo Carvalho de Melo , Ingo Molnar , Peter Zijlstra , LKML , Andi Kleen , Ian Rogers , Stephane Eranian Subject: Re: [PATCH v3] perf evsel: Fix missing exclude_{host,guest} setting Message-ID: References: <20211029224929.379505-1-namhyung@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20211029224929.379505-1-namhyung@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Oct 29, 2021 at 03:49:29PM -0700, Namhyung Kim wrote: > 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. > > Reported-by: Stephane Eranian > Signed-off-by: Namhyung Kim > --- > v3 changes) > * check memory allocation failure > * add more NULL check we were discussing this with Arnaldo yesterday and he had an idea to use evsel->pmu link to store this info instead of hash.. I first thought we needed 'evsel' related data, but after I gave it some thought I think that might actually work my argument was following usecase: cycles:G,instructions:G,pmu/bla1/:G,pmu/bla2/ that we would falsely clear pmu/bla1/:G if we used the 'evsel->pmu' data.. but then I realized it's detection if pmu support :G and so if the :G is not there, none of the events should have it thoughts? thanks, jirka > > 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 | 54 ++++++++++++++++++++++++++++++++++++----- > tools/perf/util/evsel.h | 7 ++++++ > 2 files changed, 55 insertions(+), 6 deletions(-) > > diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c > index dbfeceb2546c..d3ff4809627b 100644 > --- a/tools/perf/util/evsel.c > +++ b/tools/perf/util/evsel.c > @@ -1434,6 +1434,10 @@ void evsel__delete(struct evsel *evsel) > { > evsel__exit(evsel); > free(evsel); > + > + /* just free it for the first evsel */ > + hashmap__free(perf_missing_features.pmu); > + perf_missing_features.pmu = NULL; > } > > void evsel__compute_deltas(struct evsel *evsel, int cpu, int thread, > @@ -1791,6 +1795,23 @@ static int __evsel__prepare_open(struct evsel *evsel, struct perf_cpu_map *cpus, > return 0; > } > > +#define PMU_HASH_BITS 4 > + > +static size_t pmu_hash(const void *key, void *ctx __maybe_unused) > +{ > + const struct evsel *evsel = key; > + > + return hash_bits(evsel->core.attr.type, PMU_HASH_BITS); > +} > + > +static bool pmu_equal(const void *key1, const void *key2, void *ctx __maybe_unused) > +{ > + const struct evsel *a = key1; > + const struct evsel *b = key2; > + > + return a->core.attr.type == b->core.attr.type; > +} > + > static void evsel__disable_missing_features(struct evsel *evsel) > { > if (perf_missing_features.weight_struct) { > @@ -1807,8 +1828,14 @@ 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) > - evsel->core.attr.exclude_guest = evsel->core.attr.exclude_host = 0; > + if (perf_missing_features.exclude_guest) { > + /* we only have EXCLUDE_GUEST bit, let's skip checking */ > + if (perf_missing_features.pmu != NULL && > + hashmap__find(perf_missing_features.pmu, evsel, NULL)) { > + evsel->core.attr.exclude_guest = 0; > + evsel->core.attr.exclude_host = 0; > + } > + } > if (perf_missing_features.lbr_flags) > evsel->core.attr.branch_sample_type &= ~(PERF_SAMPLE_BRANCH_NO_FLAGS | > PERF_SAMPLE_BRANCH_NO_CYCLES); > @@ -1840,6 +1867,14 @@ int evsel__prepare_open(struct evsel *evsel, struct perf_cpu_map *cpus, > > bool evsel__detect_missing_features(struct evsel *evsel) > { > + if (perf_missing_features.pmu == NULL) { > + perf_missing_features.pmu = hashmap__new(pmu_hash, pmu_equal, NULL); > + if (IS_ERR(perf_missing_features.pmu)) { > + pr_err("Memory allocation failure!\n"); > + perf_missing_features.pmu = NULL; > + } > + } > + > /* > * Must probe features in the order they were added to the > * perf_event_attr interface. > @@ -1900,10 +1935,17 @@ 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) && > + perf_missing_features.pmu != NULL && > + !hashmap__find(perf_missing_features.pmu, evsel, NULL)) { > + uintptr_t pmu_features = PERF_MISSING_PMU_EXCLUDE_GUEST; > + > + hashmap__add(perf_missing_features.pmu, evsel, (void *)pmu_features); > + > + 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 1f7edfa8568a..11b5ece19f0e 100644 > --- a/tools/perf/util/evsel.h > +++ b/tools/perf/util/evsel.h > @@ -172,6 +172,13 @@ struct perf_missing_features { > bool data_page_size; > bool code_page_size; > bool weight_struct; > + > + /* contains enum perf_missing_pmu_features below */ > + struct hashmap *pmu; > +}; > + > +enum perf_missing_pmu_features { > + PERF_MISSING_PMU_EXCLUDE_GUEST = 1UL << 0, > }; > > extern struct perf_missing_features perf_missing_features; > -- > 2.33.1.1089.g2158813163f-goog >