Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753905AbZLZWOK (ORCPT ); Sat, 26 Dec 2009 17:14:10 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753385AbZLZWOI (ORCPT ); Sat, 26 Dec 2009 17:14:08 -0500 Received: from toro.web-alm.net ([62.245.132.31]:35238 "EHLO toro.web-alm.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752873AbZLZWOH (ORCPT ); Sat, 26 Dec 2009 17:14:07 -0500 Message-Id: <20091226214229.782692524@osadl.org> User-Agent: quilt/0.47-1 Date: Sat, 26 Dec 2009 22:41:16 +0100 From: Carsten Emde To: Steven Rostedt Cc: Ingo Molnar , Thomas Gleixner , LKML , RT-users , Carsten Emde Subject: [PATCH 2/2] add-trace_clock-to-ftrace-docs.patch References: <20091226214114.843059850@osadl.org> Content-Disposition: inline; filename=add-trace_clock-to-ftrace-docs.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1951 Lines: 49 Add an explanation of the trace variable trace_clock to the ftrace documentation. Signed-off-by: Carsten Emde Index: linux-2.6.33-rc2/Documentation/trace/ftrace.txt =================================================================== --- linux-2.6.33-rc2.orig/Documentation/trace/ftrace.txt +++ linux-2.6.33-rc2/Documentation/trace/ftrace.txt @@ -91,6 +91,33 @@ of ftrace. Here is a list of some of the This file holds the output of the trace in a human readable format (described below). + trace_clock: + + Three different clocks are available for the tracer + timestamps, "local", "medium" and "global". For the + time being, however, the "medium" clock is disabled + in the source code and requires the line + { trace_clock, "medium" }, + to be inserted in kernel/trace/trace.c between + { trace_clock_local, "local" }, + and + { trace_clock_global, "global" }, + - The "local" clock is the simplest and least coherent + tracing clock. It is useful for tracing that does not + cross to other CPUs nor does it go through idle events. + - The "medium" clock is a scalable global clock with + some jitter. It is not completely serialized, but not + completely incorrect when crossing CPUs either. + - The "global" clock is a globally monotonic, serialized + clock. It has a higher overhead than the "local" and the + "medium" trace clock but is still an order of magnitude + faster than a hardware clock based on the gettimeofday() + function would be. + + The content of trace_clock displays the available tracer + clocks, the name of the currently selected clock is + surrounded by square brackets. + trace_pipe: The output is the same as the "trace" file but this -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/