From patchwork Wed Jul 26 12:16:15 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ze Gao X-Patchwork-Id: 13327927 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 7ECC5C001B0 for ; Wed, 26 Jul 2023 12:16:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230491AbjGZMQ3 (ORCPT ); Wed, 26 Jul 2023 08:16:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32782 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229715AbjGZMQ2 (ORCPT ); Wed, 26 Jul 2023 08:16:28 -0400 Received: from mail-pg1-x52d.google.com (mail-pg1-x52d.google.com [IPv6:2607:f8b0:4864:20::52d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0C4D819A7; Wed, 26 Jul 2023 05:16:28 -0700 (PDT) Received: by mail-pg1-x52d.google.com with SMTP id 41be03b00d2f7-55ae2075990so3578900a12.0; Wed, 26 Jul 2023 05:16:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1690373787; x=1690978587; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=P/SfUH6qagd9RztYevRFo2Q3j6jWs29w7wHJ0ZcNrWE=; b=GmigUXHNKivEF+qJWOpYMSidwpXidWB/BVuh8qbB8lwRsTqUReNT9UUAdrL9YB5pff ASxe6g2NoBplCcNWZUumZT20q+Ood/JVVApgHUyhnz37V7fKpZCDWAMyGQ6xkyspP/Pz yEJw8sCXmFLiSZnQs2uw09KO3AFO5rF33dHntIqg/Ci56bl8fnnbltducGEWhBrMKdnz OvbdgPl/6Jt4P9Ok2arH86Zo3k4a0rY/IJQVvmpB+YY9t6IcFnz4u3oln39B0xIQcLrz rxHx8zAcLMx+GRSP1Gpu2oNzGjkTAUFNRhU8DLDvhHPehy5+ZE6zKkcpEQzdQKJd4yKH 7+MA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1690373787; x=1690978587; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=P/SfUH6qagd9RztYevRFo2Q3j6jWs29w7wHJ0ZcNrWE=; b=ByouSNpscg6VNGH4TjPaAnw4pjQkGd4B7U55Vm4GuP230h1x/8VE0YKORo0NjpN+4N dfQmw2njFixVa8NlUVonRqN3flaFw2jtOVEj7MxSGhde6Nr7+XCc8JbFmPwPlOOghQHP f/0KQGoDR5YdRmAwk8bJeMLzn4lckAAM17+kCkuBTWX9l7V8sFJfMxRF17oVe0SHK619 ZHIiJ2Hk7zJgGyaFm5uQSuMU2hpG4bUiUsaW6A1K58+tBCvzjc8DFIQSijwV0MFcza0M quu4Du3iGRzxBrHsmN5N4jxpL+O9AgQ8dYNFcXe08mlaBNjTlxqOMFBPSagjYanov8Ja 7nDQ== X-Gm-Message-State: ABy/qLb5aGfbEiZM+HOXomQ5ghqfvm79RdsaqTsxvI1Nk5c2AS2oeTy1 DnydbJd9GXM6kjY/Kyc5BbY= X-Google-Smtp-Source: APBJJlGE0q1zijcsm7so+mrQdJMlrjbBFw0rQBqydLkJfjQS/xtrxblvyRxdlJYD/eaC3oi36/W6iA== X-Received: by 2002:a17:90a:408f:b0:263:3386:9da8 with SMTP id l15-20020a17090a408f00b0026333869da8mr1155414pjg.49.1690373787347; Wed, 26 Jul 2023 05:16:27 -0700 (PDT) Received: from localhost.localdomain ([203.205.141.25]) by smtp.googlemail.com with ESMTPSA id ms19-20020a17090b235300b00263f446d432sm1172880pjb.43.2023.07.26.05.16.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 26 Jul 2023 05:16:26 -0700 (PDT) From: Ze Gao X-Google-Original-From: Ze Gao To: Peter Zijlstra , Steven Rostedt , Namhyung Kim Cc: Adrian Hunter , Alexander Shishkin , Arnaldo Carvalho de Melo , Ian Rogers , Ingo Molnar , Jiri Olsa , Mark Rutland , Masami Hiramatsu , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-trace-devel@vger.kernel.org, Ze Gao Subject: [RFC PATCH v2 0/3] report task state in symbolic chars from sched tracepoint Date: Wed, 26 Jul 2023 20:16:15 +0800 Message-Id: <20230726121618.19198-1-zegao@tencent.com> X-Mailer: git-send-email 2.40.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-trace-kernel@vger.kernel.org This is the 2nd attempt to fix the report task state issue in sched tracepint, here is the first version: https://lore.kernel.org/linux-trace-kernel/20230725072254.32045-1-zegao@tencent.com Against v1, add a new var to report task state in symbolic char instead of replacing the old one and to not to break anything. Acked-by: Ian Rogers Reviewed-by: Masami Hiramatsu (Google) --- In the status quo, we should see three different outcomes of the reported sched-out task state from perf-script, perf-sched-timehist, and Tp_printk of tracepoint sched_switch. And it's not hard to figure out that the former two are built upon the third one, and the reason why we see this inconsistency is that the former two does not catch up with the internal change of reported task state definitions as the kernel evolves. IMHO, exporting internal representations of task state in the tracepoint sched_switch is not a good practice and not encouraged at all, which can easily break userspace tools that relies on it. Especially when tracepoints are massively used in many observability tools nowadays due to its stable nature, which makes them no longer used for debug only purpose and we should be careful to decide what ought to be reported to userspace and what ought not. Therefore, to fix the issues mentioned above for good, instead of choosing I proposed to add a new variable to report task state in sched_switch with a symbolic character along with the old hardcoded value, and save the further processing of userspace tools and spare them from knowing implementation details in the kernel. After this patch seires, we report 'RSDTtXZPI' the same as in procfs, plus a 'p' which denotes PREEMP_ACTIVE and is used for sched_switch tracepoint only. Reviews welcome! Regards, Ze Ze Gao (2): sched, tracing: add to report task state in symbolic chars perf sched: use the new prev_state_char instead in tracepoint sched_switch include/trace/events/sched.h | 60 +++++++++++++++++++++--------------- tools/perf/builtin-sched.c | 57 ++++++---------------------------- 2 files changed, 45 insertions(+), 72 deletions(-) Ze Gao (1): libtraceevent: use the new prev_state_char instead in tracepoint sched_switch plugins/plugin_sched_switch.c | 29 ++++------------------------- 1 file changed, 4 insertions(+), 25 deletions(-)