From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 36DBE339A8; Mon, 16 Dec 2024 20:11:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734379870; cv=none; b=q/iVzhCFD2ye+cRXjbUXH3CZfA+1hZGWIA0aVG+TSNXHjv64fe28DLdL3i62FvO4WBIKZ5Iu7SDfmA2dTUKovnJ7WT4AVS3WULphiRlJ7spxQlzHImm8MA/HDugQFK8DBLHMmwKQV1EXEHPisAaYDG0fKDmGJxZHo2SVCWvfFWI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734379870; c=relaxed/simple; bh=AVjujUa5i1NdrsW0OYxxzA7RpI6eQyiJC1GvB8gcmBE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=TRzGh21XlHDOeDMZvansyI8HkGrs6sF+Z4k246+04b2zsRciIW257sjop1naIKjXmEqxO1fT586PpQhVGvh26lYlneuKotVoRU4cIOMSwVhGN8kjNEwYzU6gbz9bJmlDDFWOONqpYPSt6vwOBGCIfzdXah/KJSIL/pln6zxfUpA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=NyV6leMK; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="NyV6leMK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 392E8C4CED4; Mon, 16 Dec 2024 20:11:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1734379869; bh=AVjujUa5i1NdrsW0OYxxzA7RpI6eQyiJC1GvB8gcmBE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=NyV6leMK6fDBUsAIS20CmhVz0AjbCiR44mhETEvoEwrogYSp1a6CsI/ToBMXrPHrn jsYeHe3VE/kp3NCzik1VIEQ/GA8wq0LYZqH+3mHALyf+Jr7a39UTo4VXfZfFOLqQjG c9J0lWfY4n+nhsviUAOnGPObIPEv65nl5ki6es/U3uIi7CEbRg7UGPcfAEuRwU3wZ3 Ar3EhFqgG9QanIU9rFl7LHZhqv9M5tSZPWg+iNRJzEy/4opIjOhRRLbKCNUD/7u5EY +mDYW3PCEarsFLGMHkKUhqZVDyv7qG+lYlzKdaecoGmwkUcppJaglkmq5JbBswf+Uf oiLJOnCgTYHug== Date: Mon, 16 Dec 2024 12:11:07 -0800 From: Namhyung Kim To: Howard Chu Cc: acme@kernel.org, mark.rutland@arm.com, alexander.shishkin@linux.intel.com, jolsa@kernel.org, irogers@google.com, adrian.hunter@intel.com, kan.liang@linux.intel.com, linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v14 00/10] perf record --off-cpu: Dump off-cpu samples directly Message-ID: References: <20241215181220.754822-1-howardchu95@gmail.com> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20241215181220.754822-1-howardchu95@gmail.com> On Sun, Dec 15, 2024 at 10:12:10AM -0800, Howard Chu wrote: > Changes in v14: > - Change the internal off_cpu_thresh_us to off_cpu_thresh_ns, i.e. use > nsec instead of usec > > Changes in v13: > - Move the definition of 'off_cpu_thresh_ns' to the same commit as > dumping off-cpu samples in BPF, and give off_cpu_thresh_ns a default > value before the --off-cpu-thresh option is parsed. > > Changes in v12: > - Restore patches' bisectability, because the ordering of patches has > changed. > - Change 'us = ms * 1000' to 'us = ms * USEC_PER_MSEC' > > Changes in v11: > - Modify the options used in the off-cpu tests, as I changed the unit > of the off-cpu threshold to milliseconds. > > Changes in v10: > - Move the commit "perf record --off-cpu: Add --off-cpu-thresh option" > to where the direct sample feature is completed. > - Make --off-cpu-thresh use milliseconds as the unit. > > Changes in v9: > - Add documentation for the new option '--off-cpu-thresh', and include > an example of its usage in the commit message > - Set inherit in evsel__config() to prevent future modifications > - Support off-cpu sample data collected by perf before this patch series > > Changes in v8: > - Make this series bisectable > - Rename off_cpu_thresh to off_cpu_thresh_us and offcpu_thresh (in BPF) > to offcpu_thresh_ns for clarity > - Add commit messages to 'perf evsel: Expose evsel__is_offcpu_event() > for future use' commit > - Correct spelling mistakes in the commit message (s/is should be/should be/) > - Add kernel-doc comments to off_cpu_dump(), and comments to the empty > if block > - Add some comments to off-cpu test > - Delete an unused variable 'timestamp' in off_cpu_dump() > > Changes in v7: > - Make off-cpu event system-wide > - Use strtoull instead of strtoul > - Delete unused variable such as sample_id, and sample_type > - Use i as index to update BPF perf_event map > - MAX_OFFCPU_LEN 128 is too big, make it smaller. > - Delete some bound check as it's always guaranteed > - Do not set ip_pos in BPF > - Add a new field for storing stack traces in the tstamp map > - Dump the off-cpu sample directly or save it in the off_cpu map, not both > - Delete the sample_type_off_cpu check > - Use __set_off_cpu_sample() to parse samples instead of a two-pass parsing > > Changes in v6: > - Make patches bisectable > > Changes in v5: > - Delete unnecessary copy in BPF program > - Remove sample_embed from perf header, hard code off-cpu stuff instead > - Move evsel__is_offcpu_event() to evsel.h > - Minor changes to the test > - Edit some comments > > Changes in v4: > - Minimize the size of data output by perf_event_output() > - Keep only one off-cpu event > - Change off-cpu threshold's unit to microseconds > - Set a default off-cpu threshold > - Print the correct error message for the field 'embed' in perf data header > > Changes in v3: > - Add off-cpu-thresh argument > - Process direct off-cpu samples in post > > Changes in v2: > - Remove unnecessary comments. > - Rename function off_cpu_change_type to off_cpu_prepare_parse > > v1: > > As mentioned in: https://bugzilla.kernel.org/show_bug.cgi?id=207323 > > Currently, off-cpu samples are dumped when perf record is exiting. This > results in off-cpu samples being after the regular samples. This patch > series makes possible dumping off-cpu samples on-the-fly, directly into > perf ring buffer. And it dispatches those samples to the correct format > for perf.data consumers. > > Before: > ``` > migration/0 21 [000] 27981.041319: 2944637851 cycles:P: ffffffff90d2e8aa record_times+0xa ([kernel.kallsyms]) > perf 770116 [001] 27981.041375: 1 cycles:P: ffffffff90ee4960 event_function+0xf0 ([kernel.kallsyms]) > perf 770116 [001] 27981.041377: 1 cycles:P: ffffffff90c184b1 intel_bts_enable_local+0x31 ([kernel.kallsyms]) > perf 770116 [001] 27981.041379: 51611 cycles:P: ffffffff91a160b0 native_sched_clock+0x30 ([kernel.kallsyms]) > migration/1 26 [001] 27981.041400: 4227682775 cycles:P: ffffffff90d06a74 wakeup_preempt+0x44 ([kernel.kallsyms]) > migration/2 32 [002] 27981.041477: 4159401534 cycles:P: ffffffff90d11993 update_load_avg+0x63 ([kernel.kallsyms]) > > sshd 708098 [000] 18446744069.414584: 286392 offcpu-time: > 79a864f1c8bb ppoll+0x4b (/usr/lib/libc.so.6) > 585690935cca [unknown] (/usr/bin/sshd) > ``` > > After: > ``` > perf 774767 [003] 28178.033444: 497 cycles:P: ffffffff91a160c3 native_sched_clock+0x43 ([kernel.kallsyms]) > perf 774767 [003] 28178.033445: 399440 cycles:P: ffffffff91c01f8d nmi_restore+0x25 ([kernel.kallsyms]) > swapper 0 [001] 28178.036639: 376650973 cycles:P: ffffffff91a1ae99 intel_idle+0x59 ([kernel.kallsyms]) > swapper 0 [003] 28178.182921: 348779378 cycles:P: ffffffff91a1ae99 intel_idle+0x59 ([kernel.kallsyms]) > blueman-tray 1355 [000] 28178.627906: 100184571 offcpu-time: > 7528eef1c39d __poll+0x4d (/usr/lib/libc.so.6) > 7528edf7d8fd [unknown] (/usr/lib/libglib-2.0.so.0.8000.2) > 7528edf1af95 g_main_context_iteration+0x35 (/usr/lib/libglib-2.0.so.0.8000.2) > 7528eda4ab86 g_application_run+0x1f6 (/usr/lib/libgio-2.0.so.0.8000.2) > 7528ee6aa596 [unknown] (/usr/lib/libffi.so.8.1.4) > 7fff24e862d8 [unknown] ([unknown]) > > > blueman-tray 1355 [000] 28178.728137: 100187539 offcpu-time: > 7528eef1c39d __poll+0x4d (/usr/lib/libc.so.6) > 7528edf7d8fd [unknown] (/usr/lib/libglib-2.0.so.0.8000.2) > 7528edf1af95 g_main_context_iteration+0x35 (/usr/lib/libglib-2.0.so.0.8000.2) > 7528eda4ab86 g_application_run+0x1f6 (/usr/lib/libgio-2.0.so.0.8000.2) > 7528ee6aa596 [unknown] (/usr/lib/libffi.so.8.1.4) > 7fff24e862d8 [unknown] ([unknown]) > > > swapper 0 [000] 28178.463253: 195945410 cycles:P: ffffffff91a1ae99 intel_idle+0x59 ([kernel.kallsyms]) > dbus-broker 412 [002] 28178.464855: 376737008 cycles:P: ffffffff91c000a0 entry_SYSCALL_64+0x20 ([kernel.kallsyms]) > ``` > > Howard Chu (10): > perf evsel: Expose evsel__is_offcpu_event() for future use > perf record --off-cpu: Parse off-cpu event > perf record --off-cpu: Preparation of off-cpu BPF program > perf record --off-cpu: Dump off-cpu samples in BPF > perf evsel: Assemble offcpu samples > perf record --off-cpu: Disable perf_event's callchain collection > perf script: Display off-cpu samples correctly > perf record --off-cpu: Dump the remaining samples in BPF's stack trace > map > perf record --off-cpu: Add --off-cpu-thresh option > perf test: Add direct off-cpu test Thanks for your work and the persistence. Reviewed-by: Namhyung Kim Thanks, Namhyung > > tools/perf/Documentation/perf-record.txt | 9 ++ > tools/perf/builtin-record.c | 26 +++++ > tools/perf/builtin-script.c | 4 +- > tools/perf/tests/builtin-test.c | 1 + > tools/perf/tests/shell/record_offcpu.sh | 35 ++++++- > tools/perf/tests/tests.h | 1 + > tools/perf/tests/workloads/Build | 1 + > tools/perf/tests/workloads/offcpu.c | 16 +++ > tools/perf/util/bpf_off_cpu.c | 118 ++++++++++++++--------- > tools/perf/util/bpf_skel/off_cpu.bpf.c | 97 ++++++++++++++++++- > tools/perf/util/evsel.c | 41 +++++++- > tools/perf/util/evsel.h | 2 + > tools/perf/util/off_cpu.h | 3 +- > tools/perf/util/record.h | 1 + > 14 files changed, 297 insertions(+), 58 deletions(-) > create mode 100644 tools/perf/tests/workloads/offcpu.c > > -- > 2.43.0 >