From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030640AbbKDPcx (ORCPT ); Wed, 4 Nov 2015 10:32:53 -0500 Received: from mail.kernel.org ([198.145.29.136]:37693 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932823AbbKDPaR (ORCPT ); Wed, 4 Nov 2015 10:30:17 -0500 Message-Id: <20151104153012.941795749@goodmis.org> User-Agent: quilt/0.61-1 Date: Wed, 04 Nov 2015 10:29:45 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton Subject: [for-next][PATCH 11/13] tracing: Add some documentation about set_event_pid References: <20151104152934.825847519@goodmis.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Disposition: inline; filename=0011-tracing-Add-some-documentation-about-set_event_pid.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Steven Rostedt (Red Hat)" Update Documentation to include some comments about how to use set_event_pid. Signed-off-by: Steven Rostedt --- Documentation/trace/events.txt | 18 ++++++++++++++++++ Documentation/trace/ftrace.txt | 6 ++++++ 2 files changed, 24 insertions(+) diff --git a/Documentation/trace/events.txt b/Documentation/trace/events.txt index 75d25a1d6e42..c010be8c85d7 100644 --- a/Documentation/trace/events.txt +++ b/Documentation/trace/events.txt @@ -288,6 +288,24 @@ prev_pid == 0 # cat sched_wakeup/filter common_pid == 0 +5.4 PID filtering +----------------- + +The set_event_pid file in the same directory as the top events directory +exists, will filter all events from tracing any task that does not have the +PID listed in the set_event_pid file. + +# cd /sys/kernel/debug/tracing +# echo $$ > set_event_pid +# echo 1 > events/enabled + +Will only trace events for the current task. + +To add more PIDs without losing the PIDs already included, use '>>'. + +# echo 123 244 1 >> set_event_pid + + 6. Event triggers ================= diff --git a/Documentation/trace/ftrace.txt b/Documentation/trace/ftrace.txt index db18362c14f3..f52f297cb406 100644 --- a/Documentation/trace/ftrace.txt +++ b/Documentation/trace/ftrace.txt @@ -204,6 +204,12 @@ of ftrace. Here is a list of some of the key files: Have the function tracer only trace a single thread. + set_event_pid: + + Have the events only trace a task with a PID listed in this file. + Note, sched_switch and sched_wake_up will also trace events + listed in this file. + set_graph_function: Set a "trigger" function where tracing should start -- 2.6.1