From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 887E85674C; Fri, 22 Mar 2024 16:42:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711125770; cv=none; b=j2vDgKb2b5DPLIs2qOelhVuetO0MzGuFYOZFI99nfPyRTtnvnMDv8xopINOwyy1uXg7MLz59LcHa8cfVg4ietXMXUsKWKRjGB86bEAmf14thZleoHY/Qf1tWdOyJ+Hk7XF7+syPZMzCZbv5SMD+XndhOxclEVITjvtO8BqgLMKo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711125770; c=relaxed/simple; bh=hEsqfxJIR2reToPP0pC1oNrl0WbP9UJr+qXgdqGojAc=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=hSCaz7mK2PKwSa4isdCRBYvC49qaCiMWyOV1xsfmNwX4Fks+WMCiNHsDjHo4/KdJAyhlw+9+AEwEjd9xQ7LLOmphm8qB79+t54HISBAqfl6YFMfqU5XhFeOlNABoSfhPzwmLwVvz/OM2P5/9zya0fHStJRPKbVtrVzBrZtGQTiM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id C36F8FEC; Fri, 22 Mar 2024 09:43:21 -0700 (PDT) Received: from e126817.cambridge.arm.com (e126817.cambridge.arm.com [10.2.3.5]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id D24E43F762; Fri, 22 Mar 2024 09:42:45 -0700 (PDT) From: Ben Gainey To: peterz@infradead.org, mingo@redhat.com, acme@kernel.org, namhyung@kernel.org Cc: james.clark@arm.com, mark.rutland@arm.com, alexander.shishkin@linux.intel.com, jolsa@kernel.org, irogers@google.com, adrian.hunter@intel.com, linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, Ben Gainey Subject: [PATCH v4 0/4] perf: Support PERF_SAMPLE_READ with inherit_stat Date: Fri, 22 Mar 2024 16:42:33 +0000 Message-ID: <20240322164237.203358-1-ben.gainey@arm.com> X-Mailer: git-send-email 2.44.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit This change allows events to use PERF_SAMPLE READ with inherit so long as both inherit_stat and PERF_SAMPLE_TID are set. Currently it is not possible to use PERF_SAMPLE_READ with inherit. This restriction assumes the user is interested in collecting aggregate statistics as per `perf stat`. It prevents a user from collecting per-thread samples using counter groups from a multi-threaded or multi-process application, as with `perf record -e '{....}:S'`. Instead users must use system-wide mode, or forgo the ability to sample counter groups. System-wide mode is often problematic as it requires specific permissions (no CAP_PERFMON / root access), or may lead to capture of significant amounts of extra data from other processes running on the system. Perf already supports the ability to collect per-thread counts with `inherit` via the `inherit_stat` flag. This patch changes `perf_event_alloc` relaxing the restriction to combine `inherit` with `PERF_SAMPLE_READ` so that the combination will be allowed so long as `inherit_stat` and `PERF_SAMPLE_TID` are enabled. In this configuration stream ids (such as may appear in the read_format field of a PERF_RECORD_SAMPLE) are no longer globally unique, rather the pair of (stream id, tid) uniquely identify each event. Tools that rely on this, for example to calculate a delta between samples, would need updating to take this into account. Previously valid event configurations (system-wide, no-inherit and so on) where each stream id is the identifier are unaffected. Changes since v3: - Cleaned up perf test data changes incorrectly included into this series from elsewhere. Changes since v2: - Rebase on v6.8 - Respond to James Clarke's feedback; fixup some typos and move some repeated checks into a helper macro. - Cleaned up checkpatch lints. - Updated perf test; fixed evsel handling so that existing tests pass and added new tests to cover the new behaviour. Changes since v1: - Rebase on v6.8-rc1 - Fixed value written into sample after child exists. - Modified handling of switch-out so that context with these events take the slow path, so that the per-event/per-thread PMU state is correctly switched. - Modified perf tools to support this mode of operation. Ben Gainey (4): perf: Support PERF_SAMPLE_READ with inherit_stat tools/perf: Track where perf_sample_ids need per-thread periods tools/perf: Correctly calculate sample period for inherited SAMPLE_READ values tools/perf: Allow inherit + inherit_stat + PERF_SAMPLE_READ when opening events include/linux/perf_event.h | 1 + kernel/events/core.c | 62 ++++++++++---- tools/lib/perf/evlist.c | 1 + tools/lib/perf/evsel.c | 48 +++++++++++ tools/lib/perf/include/internal/evsel.h | 55 ++++++++++++- .../test-record-group-sampling-inherit-stat | 62 ++++++++++++++ tools/perf/util/evsel.c | 82 ++++++++++++++++++- tools/perf/util/evsel.h | 1 + tools/perf/util/session.c | 11 ++- 9 files changed, 301 insertions(+), 22 deletions(-) create mode 100644 tools/perf/tests/attr/test-record-group-sampling-inherit-stat -- 2.44.0