From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756441AbcK2RNa (ORCPT ); Tue, 29 Nov 2016 12:13:30 -0500 Received: from terminus.zytor.com ([198.137.202.10]:38792 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751268AbcK2RNV (ORCPT ); Tue, 29 Nov 2016 12:13:21 -0500 Date: Tue, 29 Nov 2016 09:13:04 -0800 From: tip-bot for Joel Fernandes Message-ID: Cc: rostedt@goodmis.org, linux-kernel@vger.kernel.org, richardcochran@gmail.com, tglx@linutronix.de, hpa@zytor.com, joelaf@google.com, prarit@redhat.com, mingo@kernel.org, john.stultz@linaro.org Reply-To: hpa@zytor.com, tglx@linutronix.de, joelaf@google.com, richardcochran@gmail.com, linux-kernel@vger.kernel.org, rostedt@goodmis.org, john.stultz@linaro.org, mingo@kernel.org, prarit@redhat.com In-Reply-To: <1480372524-15181-8-git-send-email-john.stultz@linaro.org> References: <1480372524-15181-8-git-send-email-john.stultz@linaro.org> To: linux-tip-commits@vger.kernel.org Subject: [tip:timers/core] trace: Update documentation for mono, mono_raw and boot clock Git-Commit-ID: 2924ecd441f3c12da59b297daade265f49d0831b X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 2924ecd441f3c12da59b297daade265f49d0831b Gitweb: http://git.kernel.org/tip/2924ecd441f3c12da59b297daade265f49d0831b Author: Joel Fernandes AuthorDate: Mon, 28 Nov 2016 14:35:24 -0800 Committer: Thomas Gleixner CommitDate: Tue, 29 Nov 2016 18:03:00 +0100 trace: Update documentation for mono, mono_raw and boot clock Documentation was missing for mono and mono_raw, add them and also for the boot clock introduced in this series. Signed-off-by: Joel Fernandes Signed-off-by: John Stultz Reviewed-by: Thomas Gleixner Acked-by: Steven Rostedt Cc: Prarit Bhargava Cc: Richard Cochran Link: http://lkml.kernel.org/r/1480372524-15181-8-git-send-email-john.stultz@linaro.org Signed-off-by: Thomas Gleixner --- Documentation/trace/ftrace.txt | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/Documentation/trace/ftrace.txt b/Documentation/trace/ftrace.txt index 185c39f..5596e2d 100644 --- a/Documentation/trace/ftrace.txt +++ b/Documentation/trace/ftrace.txt @@ -362,6 +362,26 @@ of ftrace. Here is a list of some of the key files: to correlate events across hypervisor/guest if tb_offset is known. + mono: This uses the fast monotonic clock (CLOCK_MONOTONIC) + which is monotonic and is subject to NTP rate adjustments. + + mono_raw: + This is the raw monotonic clock (CLOCK_MONOTONIC_RAW) + which is montonic but is not subject to any rate adjustments + and ticks at the same rate as the hardware clocksource. + + boot: This is the boot clock (CLOCK_BOOTTIME) and is based on the + fast monotonic clock, but also accounts for time spent in + suspend. Since the clock access is designed for use in + tracing in the suspend path, some side effects are possible + if clock is accessed after the suspend time is accounted before + the fast mono clock is updated. In this case, the clock update + appears to happen slightly sooner than it normally would have. + Also on 32-bit systems, it's possible that the 64-bit boot offset + sees a partial update. These effects are rare and post + processing should be able to handle them. See comments in the + ktime_get_boot_fast_ns() function for more information. + To set a clock, simply echo the clock name into this file. echo global > trace_clock