From patchwork Wed Oct 20 01:31:42 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kalesh Singh X-Patchwork-Id: 12571489 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 73514C433F5 for ; Wed, 20 Oct 2021 01:35:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4FF60610A2 for ; Wed, 20 Oct 2021 01:35:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229920AbhJTBhU (ORCPT ); Tue, 19 Oct 2021 21:37:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46622 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229910AbhJTBhT (ORCPT ); Tue, 19 Oct 2021 21:37:19 -0400 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1039EC061749 for ; Tue, 19 Oct 2021 18:35:06 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id q193-20020a252aca000000b005ba63482993so28083274ybq.0 for ; Tue, 19 Oct 2021 18:35:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:cc; bh=IYOJmQ2nEaASN59pmylXXLLP+FrglnzeH7l3JWIvSSI=; b=XGXOwhu+3ly4GGQ1oRi8qz2yqWWUke3CkXEYsjduM7C/tJS6yJeHXy2j5xGYawLq2z rb1FEnzkNVoLle2OjDHjZTO+RnowokFV8JDHe5avoDhfLbEKSnFnO2Vtk6N3UDhuSxty v+KTsqzaz9kw8ZRK+XP10KKGJhyeWhJ2IF9/ZzDlXeo28BAZ57R/6WkRD0tRd7hZRUqs nqR77wQaksmIDKYEDKZcJ7Fv9+8ByKyq5+OWyZfZh+CDUSSc/qhD/H0VKYKloOMGPEB3 lcj/VdaCp+ojGLKD7HKQPGhf/g0uwhUvK74T39GjDQecSd1WGaxrgrPT/QGdZDJEHvsV 8WoQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:cc; bh=IYOJmQ2nEaASN59pmylXXLLP+FrglnzeH7l3JWIvSSI=; b=1qX1hJMihO8/CNGhj8g2h4FlDLa5lvf1rRXevpvSxiKsPlBz55//EXXaWJvztqObEb I8TktuiHR8oRfuojYDF/OwItd52e6MageeM2HXnoIRRC5P2x3N5VTS7t9a3u75+0rhHG YAJYKLBNranOQjbbuP4K6Nv18zCnpcVYdQIas7bYDSYFi9G7pctuEUXCWifGkFapGlU4 oxrbdza/9OLglvhq173/kfFMglux8eeCbPIESsGpzLSap0jJZweTUGFxSUMsmXL2onUh oHM0QcL+qoKvM5pb4zv2TEhqYQzgq8lc7c/+LMAhL/4z01zUlcBSjfg9MQiAz0nl+Dl2 Kqqg== X-Gm-Message-State: AOAM530ECLjI4ssddXl/M+Iqn9irR6CvLJXoCHFfVnXF8qtse9NhZFwV rJEhwJDjAjFoawrXzZCJoQPtg2wHMOQAt9txuQ== X-Google-Smtp-Source: ABdhPJwdmdJ3rocY1RE5RBQflLKGa7RbWoXi5F/Gb1zI4tZm2gFPWWaQWmi5tTLT+iznoarcNeyZ7eNWYJDXAepx0Q== X-Received: from kaleshsingh.mtv.corp.google.com ([2620:15c:211:200:1953:b886:7a6c:bf0]) (user=kaleshsingh job=sendgmr) by 2002:a25:1b0a:: with SMTP id b10mr40405957ybb.520.1634693705344; Tue, 19 Oct 2021 18:35:05 -0700 (PDT) Date: Tue, 19 Oct 2021 18:31:42 -0700 In-Reply-To: <20211020013153.4106001-1-kaleshsingh@google.com> Message-Id: <20211020013153.4106001-6-kaleshsingh@google.com> Mime-Version: 1.0 References: <20211020013153.4106001-1-kaleshsingh@google.com> X-Mailer: git-send-email 2.33.0.1079.g6e70778dc9-goog Subject: [PATCH v2 5/5] tracing/histogram: Document expression arithmetic and constants From: Kalesh Singh Cc: surenb@google.com, hridya@google.com, namhyung@kernel.org, kernel-team@android.com, Kalesh Singh , Jonathan Corbet , Steven Rostedt , Ingo Molnar , Shuah Khan , Masami Hiramatsu , Tom Zanussi , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org To: unlisted-recipients:; (no To-header on input) Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org Histogram expressions now support division, and multiplication in addition to the already supported subtraction and addition operators. Numeric constants can also be used in a hist trigger expressions or assigned to a variable and used by refernce in an expression. Signed-off-by: Kalesh Singh Reviewed-by: Namhyung Kim --- Changes in v2: - Add Namhyung's Reviewed-by Documentation/trace/histogram.rst | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/Documentation/trace/histogram.rst b/Documentation/trace/histogram.rst index 533415644c54..e12699abaee8 100644 --- a/Documentation/trace/histogram.rst +++ b/Documentation/trace/histogram.rst @@ -1763,6 +1763,20 @@ using the same key and variable from yet another event:: # echo 'hist:key=pid:wakeupswitch_lat=$wakeup_lat+$switchtime_lat ...' >> event3/trigger +Expressions support the use of addition, subtraction, multiplication and +division operators (+-*/). + +Note that division by zero always returns -1. + +Numeric constants can also be used directly in an expression:: + + # echo 'hist:keys=next_pid:timestamp_secs=common_timestamp/1000000 ...' >> event/trigger + +or assigned to a variable and referenced in a subsequent expression:: + + # echo 'hist:keys=next_pid:us_per_sec=1000000 ...' >> event/trigger + # echo 'hist:keys=next_pid:timestamp_secs=common_timestamp/$us_per_sec ...' >> event/trigger + 2.2.2 Synthetic Events ----------------------