From mboxrd@z Thu Jan 1 00:00:00 1970 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 B3FE7C433EF for ; Tue, 2 Nov 2021 20:12:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9F2D56112D for ; Tue, 2 Nov 2021 20:12:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232126AbhKBUPQ (ORCPT ); Tue, 2 Nov 2021 16:15:16 -0400 Received: from mail.kernel.org ([198.145.29.99]:49510 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231669AbhKBUOf (ORCPT ); Tue, 2 Nov 2021 16:14:35 -0400 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C7215611AE; Tue, 2 Nov 2021 20:11:59 +0000 (UTC) Received: from rostedt by gandalf.local.home with local (Exim 4.95) (envelope-from ) id 1mi08U-001jP2-UG; Tue, 02 Nov 2021 16:11:58 -0400 Message-ID: <20211102201158.771485961@goodmis.org> User-Agent: quilt/0.66 Date: Tue, 02 Nov 2021 16:11:38 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton , Jonathan Corbet , Ingo Molnar , Shuah Khan , Tom Zanussi , Kalesh Singh , Masami Hiramatsu Subject: [for-next][PATCH 12/14] tracing/histogram: Document hist trigger variables References: <20211102201126.559641540@goodmis.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Kalesh Singh Update the tracefs README to describe how hist trigger variables can be created. Link: https://lkml.kernel.org/r/20211029183339.3216491-4-kaleshsingh@google.com Cc: Jonathan Corbet Cc: Ingo Molnar Cc: Shuah Khan Cc: Tom Zanussi Signed-off-by: Kalesh Singh Acked-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 985390cb8441..31a4632f9af1 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -5606,6 +5606,7 @@ 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" @@ -5617,6 +5618,16 @@ 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" -- 2.33.0