From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=74.125.82.70 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794599776; b=z40evmVoOg5Nt2RcpRH7IfLdhEZYPRdnl+UiqKsZGjeuVtwSzbhkM3qfZxbCL5jBMFfW 1pMuaPSikXsVOuefRajQRBuDRWgFKd1TYI6/kmyzJJ0WuqOFZbKZZuGU5wSsrB9my47bJ tD+nOpOloE+yztIbj9kQJq//dC11tdBkn/COM0Q9ySt+3AFh3yy66hPk7Ky35Dy+UXQia f+2FFDBZQuv2MHGT+88hFz/nAxGfqkrfINv/ng7AllESlaxo2EbxfCnyYxgP5rJjCce52 Ru4NLbpsj29N3Z6+kaqhr+gKFW4AREOdSvkowM0lBVFD33u2viAy17UpNpgm15BGbJw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794599776; h=DMARC-Filter:Received:DKIM-Signature:X-Google-DKIM-Signature: X-Forwarded-Encrypted:X-Gm-Message-State:X-Received:Date:In-Reply-To: Mime-Version:References:X-Mailer:Message-ID:Subject:From:To:Cc: Content-Type; bh=UpLlzZWrAnxDB6IGxS+hBNOhZxc/rVEG6QvTtAQK1tk=; b=UFZ323FZc0V+HidI7gzz66Hn1rxkZbh7Tl+TnzDy7mWj54USpLd33+tNEo+4y93HvZR5 zpQstbqy6htcleFfBtoKIFznQliEyfiVaDw8s2tgCvYx0Q+mrrdySEQnNGUNTgp7nM5JB Wb6isSJZrkdccWHzOzuEmkKdMHDnIzAtLPVvXs46mJELKp64tAi5XOm+jYgQj5d1tztZo p9s89BDEr952+4V12XoQWAw0mldeeKsUns3EAIuUYBGsEmf7PVehCHMK1EJvcWAPJI8dD 2lbEaApEBgT8qGjuddedzn60maKfuKPla6H97+JgjGwvXlJ14tT0w3cIeMZjTbfrnHg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=google.com; spf=pass smtp.mailfrom=flex--irogers.bounces.google.com; dkim=pass header.d=google.com header.i=@google.com header.a=rsa-sha256 header.s=20260707 header.b="P0VMPQe/"; arc=none smtp.remote-ip=74.125.82.70 Received: from mail-dl1-f70.google.com (mail-dl1-f70.google.com [74.125.82.70]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A6A3160A5BC4 for ; Fri, 13 Nov 2026 19:56:15 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org A6A3160A5BC4 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--irogers.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.a=rsa-sha256 header.s=20260707 header.b=P0VMPQe/ Received: by mail-dl1-f70.google.com with SMTP id a92af1059eb24-16bc6f3fdb1so667614c88.0 for ; Fri, 13 Nov 2026 11:56:15 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20260707; t=1794599775; x=1795204575; darn=vger.kernel.org; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:from:to:cc:subject:date:message-id:reply-to :content-type; bh=UpLlzZWrAnxDB6IGxS+hBNOhZxc/rVEG6QvTtAQK1tk=; b=P0VMPQe/HoaeWP5ICK+neE8fqvcHtvW2bSm69ha7ovmSykP1TZaxa1hzE4Y9qrNJpC w9xG5jY9C2wFtoYiWMFGUrzV7684oyOS2PZGhl+Q4N55uYddrF8Yo9ziVzijSSwjxdzB czGb/AgZ98P77pHOsABNe9/7FI14kpcbdBjfM6oVDf7I6uqdo4kWMqBC7dl0iISKVYAT 8QP6aZGA4cW8S0Hse4/SgZbJ6DT7DirFIqWbGr1KELg0A7ZhFLuo/r7fX89yZxpoayyP 83nj3kC+/sIJ72OtiKpMr1gtrEkebrvB54JTPa4W+U4wbTmGsP0g/ARH/IK78+8Kb4aa Lgkg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1794599775; x=1795204575; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=UpLlzZWrAnxDB6IGxS+hBNOhZxc/rVEG6QvTtAQK1tk=; b=rrgh+Vir3jiaptvgjRMO92VD55Lh5HjNLRBl9utCDxS+KmDBLBHNOo9q69z0vHE5z0 wGKKKdSUFAdSUIcpVx1qhk0EZUWIR2PlAOht4yBfTZNwZ0ou4CtYVvL/wB2QyDvO8Kc3 8pMn88zwrBYRqOy7Ob8OSplymC4qmHtnZ3zfpLw2PyftCYumcZPQvFRwQI0kjKSeJCQY EGHU1ekrl72+KLvmRtY87giUgemcDZaMwsjBrgfLk2vpGQ5Lwxp823jlH3WCgo47ob4j ZQ6FIBTzDyecmsbhmjYj8Maw42bbF5mnb1ubMn5iT7mQDW4oXrdrLIyfngBxx2VxPBBn aJlg== X-Forwarded-Encrypted: i=1; AL+hErFI/5ebpyAdHX7mr7P5ph7iGGnI2DHxVe9xTFRManVksLx8Sn3uaIsL6aTQ6AapvhUrArhJYyn7xsnsvfM=@vger.kernel.org X-Gm-Message-State: APuU4Z9o+59z7GN5o0HK4qJiaiw4yJcTFC+BbDtmy+V8dWHNci5+ZVOc BIrzMlIsmtsWujDJPf1tZ8dftfRmISm4tD85/Fj+B58gnGNUMAnyeDKuNLGNH6EILB6vNwqV8mj NAZrLcwnH+g== X-Received: from dlea16-n1.prod.google.com ([2002:a05:701b:4210:10b0:17d:5c89:d119]) (user=irogers job=prod-delivery.src-stubby-dispatcher) by 2002:a05:7022:3c81:b0:187:c940:21b9 with SMTP id a92af1059eb24-1b5031217d2mr2843490c88.30.1794599774451; Fri, 13 Nov 2026 11:56:14 -0800 (PST) Date: Fri, 13 Nov 2026 11:55:49 -0800 In-Reply-To: <20261113195601.2872738-1-irogers@google.com> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list Mime-Version: 1.0 References: <20261113195601.2872738-1-irogers@google.com> X-Mailer: git-send-email 2.56.1.703.gf848ed807c-goog Message-ID: <20261113195601.2872738-5-irogers@google.com> Subject: [PATCH v2 04/16] perf pmu: Probe supported sample_type flags From: Ian Rogers To: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Jiri Olsa , Ian Rogers , Adrian Hunter , James Clark Cc: linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Extend perf_pmu__probe() with probe_sample_types() to test which enum perf_event_sample_format flags are supported by the PMU. First test a common bulk sample_type mask with a single perf_event_open() call to avoid per-bit syscall overhead when all standard sample flags are supported, and then probe any remaining PERF_SAMPLE_* bits individually (configuring required companion fields such as branch_sample_type, sample_regs_user, sample_regs_intr, and sample_stack_user). Populate probed.sample_types as well as convenience booleans for branch stack, callchain, data_src, and weight sampling. Signed-off-by: Ian Rogers --- tools/perf/util/pmu.c | 99 +++++++++++++++++++++++++++++++++++++++++++ tools/perf/util/pmu.h | 13 ++++++ 2 files changed, 112 insertions(+) diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c index be93ff8b9948..d8bcf0e91f6f 100644 --- a/tools/perf/util/pmu.c +++ b/tools/perf/util/pmu.c @@ -3125,6 +3125,101 @@ static bool try_open_attr_variants(struct perf_event_attr *attr, return false; } +/* + * Probe which enum perf_event_sample_format flags are supported by @pmu, + * testing a common bulk mask first before probing individual flags. + */ +static void probe_sample_types(struct perf_pmu *pmu, + const struct perf_event_attr *base_attr, + pid_t pid, int cpu, unsigned long flags) +{ + int dummy_abi = -1; + u64 user_regs = perf_user_reg_mask(EM_HOST, &dummy_abi); + u64 intr_regs = perf_intr_reg_mask(EM_HOST, &dummy_abi); + u64 user_reg_bit = user_regs ? (user_regs & (~user_regs + 1)) : 1ULL; + u64 intr_reg_bit = intr_regs ? (intr_regs & (~intr_regs + 1)) : 1ULL; + u64 bulk_mask = PERF_SAMPLE_IP | PERF_SAMPLE_TID | PERF_SAMPLE_TIME | + PERF_SAMPLE_ADDR | PERF_SAMPLE_READ | PERF_SAMPLE_CALLCHAIN | + PERF_SAMPLE_ID | PERF_SAMPLE_CPU | PERF_SAMPLE_PERIOD | + PERF_SAMPLE_STREAM_ID | PERF_SAMPLE_RAW | PERF_SAMPLE_REGS_USER | + PERF_SAMPLE_STACK_USER | PERF_SAMPLE_WEIGHT | PERF_SAMPLE_DATA_SRC | + PERF_SAMPLE_IDENTIFIER | PERF_SAMPLE_TRANSACTION | + PERF_SAMPLE_REGS_INTR | PERF_SAMPLE_CGROUP | + PERF_SAMPLE_DATA_PAGE_SIZE | PERF_SAMPLE_CODE_PAGE_SIZE; + struct perf_event_attr b_attr = *base_attr; + int b_fd; + + b_attr.disabled = 1; + b_attr.sample_period = base_attr->sample_period ?: 10000; + b_attr.sample_type = bulk_mask; + b_attr.sample_regs_user = user_reg_bit; + b_attr.sample_regs_intr = intr_reg_bit; + b_attr.sample_stack_user = 64; + b_attr.exclude_callchain_kernel = b_attr.exclude_kernel; + b_attr.inherit = 0; + b_fd = sys_perf_event_open(&b_attr, pid, cpu, -1, flags); + if (b_fd >= 0) { + close(b_fd); + pmu->probed.sample_types |= bulk_mask; + } + + for (unsigned int shift = 0; (1ULL << shift) < PERF_SAMPLE_MAX; shift++) { + u64 bit = 1ULL << shift; + struct perf_event_attr attr = *base_attr; + int fd; + + if (pmu->probed.sample_types & bit) + continue; + + attr.disabled = 1; + attr.sample_period = base_attr->sample_period ?: 10000; + attr.sample_type = bit; + + switch (bit) { + case PERF_SAMPLE_BRANCH_STACK: + attr.branch_sample_type = PERF_SAMPLE_BRANCH_ANY | + (attr.exclude_kernel ? PERF_SAMPLE_BRANCH_USER : 0); + break; + case PERF_SAMPLE_CALLCHAIN: + attr.exclude_callchain_kernel = attr.exclude_kernel; + break; + case PERF_SAMPLE_REGS_USER: + attr.sample_regs_user = user_reg_bit; + break; + case PERF_SAMPLE_REGS_INTR: + attr.sample_regs_intr = intr_reg_bit; + break; + case PERF_SAMPLE_STACK_USER: + attr.sample_stack_user = 64; + break; + case PERF_SAMPLE_READ: + attr.inherit = 0; + break; + default: + break; + } + + fd = sys_perf_event_open(&attr, pid, cpu, -1, flags); + if (fd < 0 && bit == PERF_SAMPLE_BRANCH_STACK) { + attr.branch_sample_type = PERF_SAMPLE_BRANCH_ANY; + fd = sys_perf_event_open(&attr, pid, cpu, -1, flags); + } + if (fd < 0 && bit != PERF_SAMPLE_IP) { + attr.sample_type = PERF_SAMPLE_IP | bit; + fd = sys_perf_event_open(&attr, pid, cpu, -1, flags); + } + if (fd >= 0) { + close(fd); + pmu->probed.sample_types |= bit; + } + } + + pmu->probed.can_branch_stack = !!(pmu->probed.sample_types & PERF_SAMPLE_BRANCH_STACK); + pmu->probed.can_callchain = !!(pmu->probed.sample_types & PERF_SAMPLE_CALLCHAIN); + pmu->probed.can_data_src = !!(pmu->probed.sample_types & PERF_SAMPLE_DATA_SRC); + pmu->probed.can_weight = !!(pmu->probed.sample_types & PERF_SAMPLE_WEIGHT); +} + static void __perf_pmu__probe(struct perf_pmu *pmu, int pmu_cpu) { struct probe_candidates cands = { .nr = 0 }; @@ -3376,6 +3471,10 @@ static void __perf_pmu__probe(struct perf_pmu *pmu, int pmu_cpu) pmu->probed.can_sample = true; } + /* 2. All enum perf_event_sample_format types */ + if (pmu->probed.can_sample) + probe_sample_types(pmu, &base_attr, pid, cpu, flags); + if (keepalive_fd >= 0) close(keepalive_fd); pmu->probed.checked = true; diff --git a/tools/perf/util/pmu.h b/tools/perf/util/pmu.h index ddcd28b3cae5..658485faa05d 100644 --- a/tools/perf/util/pmu.h +++ b/tools/perf/util/pmu.h @@ -226,10 +226,23 @@ struct perf_pmu { bool can_count; /** @probed.can_sample: Supports interrupt-based sampling (sample_period > 0). */ bool can_sample; + /** @probed.can_branch_stack: Supports PERF_SAMPLE_BRANCH_STACK. */ + bool can_branch_stack; + /** @probed.can_callchain: Supports PERF_SAMPLE_CALLCHAIN. */ + bool can_callchain; + /** @probed.can_data_src: Supports PERF_SAMPLE_DATA_SRC. */ + bool can_data_src; + /** @probed.can_weight: Supports PERF_SAMPLE_WEIGHT. */ + bool can_weight; /** @probed.probe_event: Name of the event used to probe the PMU. */ char *probe_event; /** @probed.open_err: errno if open_supported is false. */ int open_err; + /** + * @probed.sample_types: Bitmask of supported + * enum perf_event_sample_format flags. + */ + u64 sample_types; } probed; }; -- 2.56.1.703.gf848ed807c-goog