From: tip-bot for Joel Fernandes <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
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
Subject: [tip:timers/core] trace: Update documentation for mono, mono_raw and boot clock
Date: Tue, 29 Nov 2016 09:13:04 -0800 [thread overview]
Message-ID: <tip-2924ecd441f3c12da59b297daade265f49d0831b@git.kernel.org> (raw)
In-Reply-To: <1480372524-15181-8-git-send-email-john.stultz@linaro.org>
Commit-ID: 2924ecd441f3c12da59b297daade265f49d0831b
Gitweb: http://git.kernel.org/tip/2924ecd441f3c12da59b297daade265f49d0831b
Author: Joel Fernandes <joelaf@google.com>
AuthorDate: Mon, 28 Nov 2016 14:35:24 -0800
Committer: Thomas Gleixner <tglx@linutronix.de>
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 <joelaf@google.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Link: http://lkml.kernel.org/r/1480372524-15181-8-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
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
prev parent reply other threads:[~2016-11-29 17:13 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-28 22:35 [GIT PULL][PATCH 0/7] Timekeeping changes for 4.10 (take 2) John Stultz
2016-11-28 22:35 ` [PATCH 1/7] selftests/timers: Fix spelling mistake "Asyncrhonous" -> "Asynchronous" John Stultz
2016-11-29 17:10 ` [tip:timers/core] " tip-bot for Colin Ian King
2016-11-28 22:35 ` [PATCH 2/7] timekeeping: Ignore the bogus sleep time if pm_trace is enabled John Stultz
2016-11-29 7:19 ` Ingo Molnar
2016-11-29 9:38 ` Chen Yu
2016-11-29 17:10 ` [tip:timers/core] " tip-bot for Chen Yu
2016-11-28 22:35 ` [PATCH 3/7] timekeeping: clocksource_cyc2ns: Document intended range limitation John Stultz
2016-11-29 17:11 ` [tip:timers/core] timekeeping/clocksource_cyc2ns: " tip-bot for Chris Metcalf
2016-11-28 22:35 ` [PATCH 4/7] time: alarmtimer: Add the tracepoints for alarmtimer John Stultz
2016-11-29 7:23 ` Ingo Molnar
2016-11-29 8:23 ` Baolin Wang
2016-11-29 9:12 ` Ingo Molnar
2016-11-29 11:52 ` Baolin Wang
2016-11-29 12:06 ` Thomas Gleixner
2016-11-30 11:43 ` Baolin Wang
2016-12-01 2:34 ` Baolin Wang
2016-12-01 13:52 ` [tip:timers/core] alarmtimer: Add tracepoints for alarm timers tip-bot for Baolin Wang
2016-11-28 22:35 ` [PATCH 5/7] timekeeping: Add a fast and NMI safe boot clock John Stultz
2016-11-29 17:11 ` [tip:timers/core] " tip-bot for Joel Fernandes
2016-11-28 22:35 ` [PATCH 6/7] trace: Add an option for boot clock as trace clock John Stultz
2016-11-28 23:05 ` Steven Rostedt
2016-11-29 17:12 ` [tip:timers/core] " tip-bot for Joel Fernandes
2016-11-28 22:35 ` [PATCH 7/7] trace: Update documentation for mono, mono_raw and boot clock John Stultz
2016-11-28 23:07 ` Steven Rostedt
2016-11-29 7:26 ` Ingo Molnar
2016-11-29 16:10 ` Joel Fernandes
2016-11-29 16:11 ` Thomas Gleixner
2016-11-29 17:13 ` tip-bot for Joel Fernandes [this message]
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