From patchwork Fri Apr 22 05:33:57 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Namhyung Kim X-Patchwork-Id: 12822753 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 1E9D1C4332F for ; Fri, 22 Apr 2022 05:37:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231888AbiDVFkB (ORCPT ); Fri, 22 Apr 2022 01:40:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57862 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233252AbiDVFg4 (ORCPT ); Fri, 22 Apr 2022 01:36:56 -0400 Received: from mail-pl1-x630.google.com (mail-pl1-x630.google.com [IPv6:2607:f8b0:4864:20::630]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 45FC64F445; Thu, 21 Apr 2022 22:34:04 -0700 (PDT) Received: by mail-pl1-x630.google.com with SMTP id q1so7326529plx.13; Thu, 21 Apr 2022 22:34:04 -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=A3WwvYrCiMoXiXB8bkTFdVRHDp/BLWRJVTqviHh1CBQ=; b=j24LGTSEVZulAYCf/lkSnkfaRGHDyZ6p+O2hu/4bVvK8fI30rwFK3lBDScOR70vHN0 sXSR1qzT2C2Fg4R30OUV6By6DT7T26UUj1tEgGE6OAAAnr4dYx4F1x18vnZN4b+XkpZW oXtjuslbNU4gYvIguhm/Oh2Hx96JieES23/yw+LuIkvDFifxWYP/McvoZDLi0iXWfAze boh0R1Son2MEYNq/RZaiMlJwhwaWf69VuSj7U3QKOUtrOuSgHOLKGKkz5eHdnzh60QWn PhXCjjuyFw6RudVN3jm9aTg28LlL0WU9lden6j6cCA77QGcYUl8vEkxOyxzA6WiSQ6iX PiaQ== 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=A3WwvYrCiMoXiXB8bkTFdVRHDp/BLWRJVTqviHh1CBQ=; b=0WOonxvOL29JwoiOoXAfyWCtvDb86dgeZkxThZh/N6XjnzMLcTBJxmkwqQxApOJtI7 9/ej5AgSG3cFKjaSY6Wp1wtRRT0OUQYRH02f0Y6Eh9jUb4vSsduPO1erHfm4I8A/xAqT Uv2T6H4y99PYZwXxs3acLfU9BOnXHLoDba2/X0L4dYrzqjMywS3KW9Ktlg5mY/QZ23ij mnCrbU/v61w37wpktvLMFKJPtWXZ/0LQN0yXelclFKjMZO1bHLh52ETdUEj93lkNi2TH EJxws8veps9cQCG5+fFuQwE0PzCzCGoUnNa8kOAXV25OtKQVjhIlnV/uNSs0lQ5tX06v CJWA== X-Gm-Message-State: AOAM530DmkTCb2MTw9znJEf3t+ZiZn0+bhFjexmrtGjOE1ji9J8C2iut Eb0/UVsovcJwweuKGrgKKVQUiUFubOU= X-Google-Smtp-Source: ABdhPJxh6Cpm3ngQB+oSWcZu103J5MQpio+rtTSaFlo35CS84011RtLat/k7inehKOjm3grGmk8MJw== X-Received: by 2002:a17:902:6a8a:b0:156:8ff6:daf0 with SMTP id n10-20020a1709026a8a00b001568ff6daf0mr2847853plk.117.1650605643561; Thu, 21 Apr 2022 22:34:03 -0700 (PDT) Received: from balhae.hsd1.ca.comcast.net ([2601:647:4f00:3590:32e3:a023:46c1:80cd]) by smtp.gmail.com with ESMTPSA id 204-20020a6302d5000000b00385f29b02b2sm886519pgc.50.2022.04.21.22.34.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 21 Apr 2022 22:34:02 -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 , bpf@vger.kernel.org, linux-perf-users@vger.kernel.org, Blake Jones Subject: [RFC 0/4] perf record: Implement off-cpu profiling with BPF (v1) Date: Thu, 21 Apr 2022 22:33:57 -0700 Message-Id: <20220422053401.208207-1-namhyung@kernel.org> X-Mailer: git-send-email 2.36.0.rc2.479.g8af0fa9b8e-goog MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-State: RFC Hello, This is the first 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. 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-v1' 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/Makefile.perf | 1 + tools/perf/builtin-record.c | 21 ++ tools/perf/util/Build | 1 + tools/perf/util/bpf_off_cpu.c | 301 +++++++++++++++++++++++++ tools/perf/util/bpf_skel/off_cpu.bpf.c | 214 ++++++++++++++++++ tools/perf/util/evsel.c | 4 +- 6 files changed, 540 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 base-commit: 41204da4c16071be9090940b18f566832d46becc