From patchwork Thu Oct 28 19:57:57 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kalesh Singh X-Patchwork-Id: 12590961 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 C3BDFC433EF for ; Thu, 28 Oct 2021 19:58:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A4443604AC for ; Thu, 28 Oct 2021 19:58:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231158AbhJ1UAt (ORCPT ); Thu, 28 Oct 2021 16:00:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50622 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230342AbhJ1UAs (ORCPT ); Thu, 28 Oct 2021 16:00:48 -0400 Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AC0FDC061745 for ; Thu, 28 Oct 2021 12:58:21 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id v18-20020a25fc12000000b005c1f3933580so3448351ybd.2 for ; Thu, 28 Oct 2021 12:58:21 -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=aL9ForBXeqIt4axGE+MJntx+0cHbs1gItbc8kj8VTwA=; b=iK242DvbTA3vdISimfzLPV0oBXKg5wDnG2LSTdzxQlmZVUx9hkOqy0Phj04oNDpQf0 f8X0Dj8lEfABj4r3D7lTSImo2f3VnMh/d2v8fVwD3Kv6pFOdI/5qjms/epVDFSs7CTpA EITRmLPqOGYHiHJw8bmACSOkRCB9DTBiYY7aETpEsi3+mxbIlnOfPShwLKGL9HODy8w8 INYuwJPNdgXAiIstfpMv0ZLUq6X797UA3occ+/IT2caEsDvC7XoVH4RfLNNmOr0iqn4o lVkOb58XLQEuH6iFAWurtDmcjZWrQSaOUP/JecjxAMYbkTzc67pnx37jIspMMcNvWYwh /eKg== 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=aL9ForBXeqIt4axGE+MJntx+0cHbs1gItbc8kj8VTwA=; b=reJbPw3uCJtKcZwhtr7NdmZf+3gYvYYZctZGUWjQzpBfNY/HNMvsvzIXsnts4yHoHl AgnPQdT6sZ5uweAyk0SSxepL0LH82I1z32As+v+rBUz25zdYHAc8N+pHEX1RQgpWxjhq eBXtZYFL4KDXIuE1R7jCEZJdMOrEeagAno84anpLtMu8P0MPvNO4PxwN2JbiCz9em5Bl b0ldfk38Hg2DHaOZp9Lq4c+TyYgzrUc5a4v8yskKj0xVheL+CnInpOQ7jNLiQ34oJkAF oH3iSbAXjYhPp47M4awL+ebyTrzTvVk59yvcVjkfrb5rXAC3aiQtX0Arshfom7O1ayG6 jEcA== X-Gm-Message-State: AOAM5322AlrzHCSqRBtmWBoiFkbwNY7mAkQjL55YGRwCK1i1EqxiW4IC WSv/NpE1ANKTfTFUWg+N9XC4Bq/S/TSuUUaWYQ== X-Google-Smtp-Source: ABdhPJx//FjYoSzF9kQHCnJJLt5scSSG8QbWdBzunL9KbVJ/0PnHskFoUolLtZ1d8SkNtUgtn2Anvkt4Q5C63rP5Cw== X-Received: from kaleshsingh.mtv.corp.google.com ([2620:15c:211:200:9b57:752f:2f0a:3a13]) (user=kaleshsingh job=sendgmr) by 2002:a25:880e:: with SMTP id c14mr6965833ybl.55.1635451100900; Thu, 28 Oct 2021 12:58:20 -0700 (PDT) Date: Thu, 28 Oct 2021 12:57:57 -0700 In-Reply-To: <20211028195805.2684854-1-kaleshsingh@google.com> Message-Id: <20211028195805.2684854-2-kaleshsingh@google.com> Mime-Version: 1.0 References: <20211028195805.2684854-1-kaleshsingh@google.com> X-Mailer: git-send-email 2.33.0.1079.g6e70778dc9-goog Subject: [PATCH v2 1/2] tracing/histogram: Document hist trigger variables From: Kalesh Singh Cc: surenb@google.com, hridya@google.com, namhyung@kernel.org, kernel-team@android.com, rostedt@goodmis.org, mhiramat@kernel.org, Kalesh Singh , Ingo Molnar , Shuah Khan , 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 Update the tracefs README to describe how hist trigger variables can be created. Signed-off-by: Kalesh Singh Acked-by: Masami Hiramatsu --- Changes in v2: - Add Masami's Acked-by. kernel/trace/trace.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index bc677cd64224..c41b3786401d 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -5628,6 +5628,7 @@ static const char readme_msg[] = #ifdef CONFIG_HIST_TRIGGERS " hist trigger\t- If set, event hits are aggregated into a hash table\n" "\t Format: hist:keys=\n" + "\t [:=[,=...]]\n" "\t [:values=]\n" "\t [:sort=]\n" "\t [:size=#entries]\n" @@ -5639,6 +5640,16 @@ static const char readme_msg[] = "\t common_timestamp - to record current timestamp\n" "\t common_cpu - to record the CPU the event happened on\n" "\n" + "\t A hist trigger variable can be:\n" + "\t - a reference to a field e.g. x=current_timestamp,\n" + "\t - a reference to another variable e.g. y=$x,\n" + "\t - a numeric literal: e.g. ms_per_sec=1000,\n" + "\t - an arithmetic expression: e.g. time_secs=current_timestamp/1000\n" + "\n" + "\t hist trigger aritmethic expressions support addition(+), subtraction(-),\n" + "\t multiplication(*) and division(/) operators. An operand can be either a\n" + "\t variable reference, field or numeric literal.\n" + "\n" "\t When a matching event is hit, an entry is added to a hash\n" "\t table using the key(s) and value(s) named, and the value of a\n" "\t sum called 'hitcount' is incremented. Keys and values\n"