From patchwork Fri May 6 20:16:23 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Namhyung Kim X-Patchwork-Id: 12841572 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 67377C433F5 for ; Fri, 6 May 2022 20:16:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1442134AbiEFUUS (ORCPT ); Fri, 6 May 2022 16:20:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47470 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1442115AbiEFUUR (ORCPT ); Fri, 6 May 2022 16:20:17 -0400 Received: from mail-pj1-x102f.google.com (mail-pj1-x102f.google.com [IPv6:2607:f8b0:4864:20::102f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ED2684D624; Fri, 6 May 2022 13:16:30 -0700 (PDT) Received: by mail-pj1-x102f.google.com with SMTP id z5-20020a17090a468500b001d2bc2743c4so7797811pjf.0; Fri, 06 May 2022 13:16:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=sender:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=PnVTOmeWJdCW14+Uuj8JCfjLjJAP80qHcxM/0JW5PeM=; b=Q17S6sSUCOxqpIi7tYiyZjfz/LZE9iOczEusYqcnh/qTIAK4z0g9ba9B+ZHC7cDO8h zdq7bfUqSyiVYofBGVGAcjLSI68sWnISGiF9a7BEKSumngEivjgm+q+x0QenAq/PMmMg Cb/9QYkw7lV/497WBHacu+BsKwpResU+vEFAh6vOMLYxBY1DbSI2OpdfyPNrhp2f0p2R pEWnZJJZw0ZlcL0IMesBmRB4aKCXeaLwaKv9QAVA9AKp7MzcMQEAyAI6oB0+oPMT7dW3 koscAj6DLcFGofqU9ZtIWnn9oj4n/DII3dhxUWbWH6c4J4HGbCejSZot50hydHNxh1Xo s8AA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:sender:from:to:cc:subject:date:message-id :mime-version:content-transfer-encoding; bh=PnVTOmeWJdCW14+Uuj8JCfjLjJAP80qHcxM/0JW5PeM=; b=uBPS7eINyPamvFqvEm4FlBcwDJ+ktE673cLD7D35zkO4DmXso65SVEmk0EYfJXcOYi xESFhBfE5FuDgCZ+04mBfmu0wzEGWM+DSxVva4tOdHaPpuczXENy1R/PsXnWBRM7UMrS jdQVSU+fTtSA+6Vw0qKugArjxHbjwA6XIzIkAOFu45V2wWdaWCjpLYuM8NW4U6cZGJAk i+++rBty+J0hf6cQiraGvpyvlP7x7LZpsCaoNJ3imQcCWDNxGa2ro7OECXPFY/JzBJQc 1axBkCprBLeXCqNkLKD8FLXA958VWCKLYeoViAIX+o+ekKR161WH1h/X0QiYczvjBKNS ISoA== X-Gm-Message-State: AOAM530MWxqufp+rceDV6hGV3janPIA5amccaap46z+FuKnRnKlrSw8U FwaMSDiWyyFu1YMRRXp3sYI= X-Google-Smtp-Source: ABdhPJyLVsfwZY95sq/VCjUFwjdh4dXE1f5LgZRey1ziDDJSCSZVuoavnF4ICtShwhNrA4pGt/6a0w== X-Received: by 2002:a17:90b:4b0d:b0:1dc:3d21:72c1 with SMTP id lx13-20020a17090b4b0d00b001dc3d2172c1mr14403583pjb.21.1651868190390; Fri, 06 May 2022 13:16:30 -0700 (PDT) Received: from balhae.hsd1.ca.comcast.net ([2601:647:4f00:3590:a5d1:d7b7:dd61:c87b]) by smtp.gmail.com with ESMTPSA id m2-20020a170902db8200b0015e8d4eb268sm2160156pld.178.2022.05.06.13.16.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 06 May 2022 13:16:29 -0700 (PDT) Sender: Namhyung Kim From: Namhyung Kim To: Arnaldo Carvalho de Melo , Jiri Olsa Cc: Ingo Molnar , Peter Zijlstra , LKML , Andi Kleen , Ian Rogers , Song Liu , Hao Luo , Milian Wolff , bpf@vger.kernel.org, linux-perf-users@vger.kernel.org, Blake Jones Subject: [RFC 0/4] perf record: Implement off-cpu profiling with BPF (v2) Date: Fri, 6 May 2022 13:16:23 -0700 Message-Id: <20220506201627.85598-1-namhyung@kernel.org> X-Mailer: git-send-email 2.36.0.512.ge40c2bad7a-goog MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-State: RFC Hello, This is the second version of off-cpu profiling support. Together with (PMU-based) cpu profiling, it can show holistic view of the performance characteristics of your application or system. Changes in v2) * change sched_switch argument handling (Andrii) * use task local storage (Hao) * fix build error on !BUILD_BPF_SKEL (kernel test robot) * add documentation regard fp callstack (Milian) With BPF, it can aggregate scheduling stats for interested tasks and/or states and convert the data into a form of perf sample records. I chose the bpf-output event which is a software event supposed to be consumed by BPF programs and renamed it as "offcpu-time". So it requires no change on the perf report side except for setting sample types of bpf-output event. Basically it collects userspace callstack for tasks as it's what users want mostly. Maybe we can add support for the kernel stacks but I'm afraid that it'd cause more overhead. So the offcpu-time event will always have callchains regardless of the command line option, and it enables the children mode in perf report by default. It adds --off-cpu option to perf record like below: $ sudo perf record -a --off-cpu -- perf bench sched messaging -l 1000 # Running 'sched/messaging' benchmark: # 20 sender and receiver processes per group # 10 groups == 400 processes run Total time: 1.518 [sec] [ perf record: Woken up 9 times to write data ] [ perf record: Captured and wrote 5.313 MB perf.data (53341 samples) ] Then we can run perf report as usual. The below is just to skip less important parts. $ sudo perf report --stdio --call-graph=no --percent-limit=2 # To display the perf.data header info, please use --header/--header-only options. # # # Total Lost Samples: 0 # # Samples: 52K of event 'cycles' # Event count (approx.): 42522453276 # # Children Self Command Shared Object Symbol # ........ ........ ............... ................ .................................. # 9.58% 9.58% sched-messaging [kernel.vmlinux] [k] audit_filter_rules.constprop.0 8.46% 8.46% sched-messaging [kernel.vmlinux] [k] audit_filter_syscall 4.54% 4.54% sched-messaging [kernel.vmlinux] [k] copy_user_enhanced_fast_string 2.94% 2.94% sched-messaging [kernel.vmlinux] [k] unix_stream_read_generic 2.45% 2.45% sched-messaging [kernel.vmlinux] [k] memcg_slab_free_hook # Samples: 983 of event 'offcpu-time' # Event count (approx.): 684538813464 # # Children Self Command Shared Object Symbol # ........ ........ ............... .................... .......................... # 83.86% 0.00% sched-messaging libc-2.33.so [.] __libc_start_main 83.86% 0.00% sched-messaging perf [.] cmd_bench 83.86% 0.00% sched-messaging perf [.] main 83.86% 0.00% sched-messaging perf [.] run_builtin 83.64% 0.00% sched-messaging perf [.] bench_sched_messaging 41.35% 41.35% sched-messaging libpthread-2.33.so [.] __read 38.88% 38.88% sched-messaging libpthread-2.33.so [.] __write 3.41% 3.41% sched-messaging libc-2.33.so [.] __poll The perf bench sched messaging created 400 processes to send/receive messages through unix sockets. It spent a large portion of cpu cycles for audit filter and read/copy the messages while most of the offcpu-time was in read and write calls. You can get the code from 'perf/offcpu-v2' branch in my tree at git://git.kernel.org/pub/scm/linux/kernel/git/namhyung/linux-perf.git Enjoy! :) Thanks, Namhyung Namhyung Kim (4): perf report: Do not extend sample type of bpf-output event perf record: Enable off-cpu analysis with BPF perf record: Implement basic filtering for off-cpu perf record: Handle argument change in sched_switch tools/perf/Documentation/perf-record.txt | 10 + tools/perf/Makefile.perf | 1 + tools/perf/builtin-record.c | 21 ++ tools/perf/util/Build | 1 + tools/perf/util/bpf_off_cpu.c | 298 +++++++++++++++++++++++ tools/perf/util/bpf_skel/off_cpu.bpf.c | 209 ++++++++++++++++ tools/perf/util/evsel.c | 4 +- tools/perf/util/off_cpu.h | 24 ++ 8 files changed, 566 insertions(+), 2 deletions(-) create mode 100644 tools/perf/util/bpf_off_cpu.c create mode 100644 tools/perf/util/bpf_skel/off_cpu.bpf.c create mode 100644 tools/perf/util/off_cpu.h base-commit: 33cd6928039c6bf18cf0baec936924d908e6c89b