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 18326C433EF for ; Tue, 26 Oct 2021 18:32:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EB2BF60F9B for ; Tue, 26 Oct 2021 18:32:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238328AbhJZSe3 (ORCPT ); Tue, 26 Oct 2021 14:34:29 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:40454 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230483AbhJZSe2 (ORCPT ); Tue, 26 Oct 2021 14:34:28 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1635273124; 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=f6pSoHrzFEYek0223M2oApqe/5UK7C/flZHJtZGdaKY=; b=JkOxtUAnFRzoyjpzM/hp/GzSy4kbdQovGeYJZglv4DiNZcMCRkd54QNfAFMDxwceLjM9RK G5gBkOYD+rZRcZRXlm3I2wGfxU2Ct8fsVdxLDwEvgJIvDAQoLPCuoqMiZNSkEYkbWlQtWg KihU7iMxlLnQo81FTt4Tjv3CAk7iFj8= Received: from mail-wm1-f69.google.com (mail-wm1-f69.google.com [209.85.128.69]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-470-oTYx06uiNr69xFPKBFYeEA-1; Tue, 26 Oct 2021 14:32:02 -0400 X-MC-Unique: oTYx06uiNr69xFPKBFYeEA-1 Received: by mail-wm1-f69.google.com with SMTP id j38-20020a05600c1c2600b0032ccf96ea8eso33012wms.1 for ; Tue, 26 Oct 2021 11:32:02 -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=f6pSoHrzFEYek0223M2oApqe/5UK7C/flZHJtZGdaKY=; b=t6+/6N3I0gtq43jG76tPT1f3qqfo2HisXymbEB1LxHv6RV/u11Ci9A649jAJUAFmr6 BvOsWXpu5nciGPq7VGiN5hwveFFI0OvfsjWHBHCT5UJ62xhAOhVSUXb78kx41XYdzgoQ hsNQrsd2e4aMGiaRW2l6Ews81dWWzgHclU0Q6YB3bgdQEUGakhMJNCoSh9ADBT0hRilU J4zRCUSL2bmo8w4RpwF07r3/MZ+UjE0X6kq53huxAEV33CIO7wv4VbMyvUJrc6Dk9vtX ypIKPwA/exmUpwUa+woTOkAqquid9747Qu/hsquueZ/DTeMegZBEP/nYcA/CZ/wp1xHh rD5w== X-Gm-Message-State: AOAM532SvHWMCCVyLh6VZdGoW5QAJUXfmFAWSJi+3wsR0bxCiaa+b46W PW8zxd8rbSjb29YnkCk4oJbUjyeZt+TUBw5JceQb07yoQFL9fjU0M5krdLEk9EYT82PE383nMUr dLZdY7VPcL8P5H1n05Yv1lHw2 X-Received: by 2002:a05:6000:2c2:: with SMTP id o2mr34691379wry.194.1635273121541; Tue, 26 Oct 2021 11:32:01 -0700 (PDT) X-Google-Smtp-Source: ABdhPJwnLUqQTK0PIG2QP9VGljoN5Qj/XBM8jVg3Cd5CQmCqll0fpzOMoEbahJ47iwL44t2zeGBYVQ== X-Received: by 2002:a05:6000:2c2:: with SMTP id o2mr34691361wry.194.1635273121346; Tue, 26 Oct 2021 11:32:01 -0700 (PDT) Received: from krava ([83.240.63.48]) by smtp.gmail.com with ESMTPSA id p11sm1371031wmi.0.2021.10.26.11.32.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 26 Oct 2021 11:32:01 -0700 (PDT) Date: Tue, 26 Oct 2021 20:31:59 +0200 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 v2] perf evsel: Fix missing exclude_{host,guest} setting Message-ID: References: <20211026043351.56662-1-namhyung@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20211026043351.56662-1-namhyung@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Oct 25, 2021 at 09:33:51PM -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 > --- > 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 | 47 +++++++++++++++++++++++++++++++++++------ > tools/perf/util/evsel.h | 7 ++++++ > 2 files changed, 48 insertions(+), 6 deletions(-) > > diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c > index dbfeceb2546c..f33801b4615d 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; should this just remove evsel from perf_missing_features.pmu? I'm not sure when we should actually release this.. what's your rationale for releasing it in here? > } > > 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 +1828,13 @@ 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 (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 +1866,9 @@ 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); missing allocation fail check thanks, jirka > + > /* > * Must probe features in the order they were added to the > * perf_event_attr interface. > @@ -1900,10 +1929,16 @@ 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) && > + !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; > -- > 2.33.0.1079.g6e70778dc9-goog >