From patchwork Mon Oct 25 19:23:19 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kalesh Singh X-Patchwork-Id: 12582777 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 4E3F4C433F5 for ; Mon, 25 Oct 2021 20:05:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2965360E0B for ; Mon, 25 Oct 2021 20:05:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236954AbhJYUHw (ORCPT ); Mon, 25 Oct 2021 16:07:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60426 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234944AbhJYUGD (ORCPT ); Mon, 25 Oct 2021 16:06:03 -0400 Received: from mail-qv1-xf49.google.com (mail-qv1-xf49.google.com [IPv6:2607:f8b0:4864:20::f49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 29937C036D6F for ; Mon, 25 Oct 2021 12:26:04 -0700 (PDT) Received: by mail-qv1-xf49.google.com with SMTP id el19-20020ad459d3000000b00384a5ef8979so11677562qvb.18 for ; Mon, 25 Oct 2021 12:26:04 -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=kE3Nv1lKwT793xJwq+iC3RoCHqpYdQS3Tip3semgyOw=; b=gbn9eg9008NdXKZ1/pxplWbq1W+HOEpi3W3HkUpPW4ebJu/REMlQr1QF8rl6mQIeob euAGzvS+dOzo0OLG8Dvw/ls/OC6sl5N7rY/bFIaEZ6MMC/DFS3XjRDLrySKoPcl0Onwf TR3XD9K2yr65MzjufGS4Maq/H7ORSIxQQeGN/v+vTFrEH7F7Uo1xD6t4IqUj10V2a6GA RwWq00Ic7WNkanKG1SVkDRvdAP398xy1awfqdfjX+8zrnFqsgafTBYlGR+ZD+rxq8olq Qlsg3CtIduhiPG9cLfEDQ56Rujasnsz4EppRxtlTl7M8mxnvBNOn73lnj4mIxM1QQ5/s TgbA== 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=kE3Nv1lKwT793xJwq+iC3RoCHqpYdQS3Tip3semgyOw=; b=1H48bKbWB2QbCWPgwYGNGpK/d3wzVxBnMSFj9lMKQwQ9My366PucnpQx/yAVpT7X3c rlwOp+CEKb6PEdB2u/lxLzynEpvubLz5EBqMXdxOQ+F5wH3P3o9HxvCE6pry9aNJPI71 /pGwalc0de/Gu1g4E9uHoJSepJZlTbGja/bLTsLwtx0xI2CE4GyJdjrcAF/cwed+7mSH UurZy1iI2DAahuxrkPjqFErpDwzroyMhFgcvrgEhNHZEXu1oZL793k5cFQCofTBLikqW GcEYAe0M/ndm0ZqWuZRzukXkv95i8Abt4TCOMCmrEkkhUA5UbCelAnnJp97djpv9wIrW 5L7Q== X-Gm-Message-State: AOAM531zQN3AnsHfX9bPWS4irkKnZWltLEtXBdkst01R4Z8SMM/Vby9P bU8U6L8xmRO8xT1p2ADM43pTBNf/vXTxnL1RKg== X-Google-Smtp-Source: ABdhPJz0CM9pT2MDiX5onT9xQHkFssm++CsGBJiIKiL0pdTsJ/7A8JCL2uHFhTnN92yeJZ01BIcWoG5+gyc3y2cP1Q== X-Received: from kaleshsingh.mtv.corp.google.com ([2620:15c:211:200:b783:5702:523e:d435]) (user=kaleshsingh job=sendgmr) by 2002:a05:622a:1a0b:: with SMTP id f11mr19780649qtb.133.1635189963298; Mon, 25 Oct 2021 12:26:03 -0700 (PDT) Date: Mon, 25 Oct 2021 12:23:19 -0700 In-Reply-To: <20211025192330.2992076-1-kaleshsingh@google.com> Message-Id: <20211025192330.2992076-9-kaleshsingh@google.com> Mime-Version: 1.0 References: <20211025192330.2992076-1-kaleshsingh@google.com> X-Mailer: git-send-email 2.33.0.1079.g6e70778dc9-goog Subject: [PATCH v3 8/8] 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 ----------------------