From: Ingo Molnar <mingo@elte.hu>
To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>,
Steven Rostedt <rostedt@goodmis.org>,
Zhaolei <zhaolei@cn.fujitsu.com>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 0/3] Add walltime support for ring-buffer
Date: Mon, 3 Aug 2009 09:22:55 +0200 [thread overview]
Message-ID: <20090803072255.GB27581@elte.hu> (raw)
In-Reply-To: <20090728105931.D801.A69D9226@jp.fujitsu.com>
* KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> wrote:
> It can. but I don't think it is sufficient. On flight recorder
> use-case, The tracing run more than one year. And, Administrator
> only see last N sec log. (previous logs were overwritten by
> ring-buffer go-around)
That's definitely something we want to enable ASAP.
I'm wondering why a single u64 timestamp is not enough to express
the full, absolute range of time elapsed since bootup, in
nanoseconds.
That would make walltime a matter of pretty-printing only - we'd
have to convert the u64 nsec timestamp into a walltime format,
right?
In fact we could change all the timestamps to be standardized along
'nanoseconds elapsed since 1970' or so - not nanoseconds since the
last bootup. That still fits just fine within 64 bits - u64
nanoseconds has a scope of 500+ years.
Ingo
next prev parent reply other threads:[~2009-08-03 7:23 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-07-24 10:40 Zhaolei
2009-07-24 10:42 ` [PATCH] " Zhaolei
2009-07-24 10:47 ` Zhaolei
2009-07-24 10:43 ` [RFC PATCH 1/3] " Zhaolei
2009-07-24 10:43 ` [RFC PATCH 2/3] Apply walltime-supporting functions to trace system Zhaolei
2009-07-24 10:44 ` [RFC PATCH 3/3] Make ftrace display walltime in output Zhaolei
2009-07-24 13:05 ` [PATCH 0/3] Add walltime support for ring-buffer Steven Rostedt
2009-07-28 1:43 ` KOSAKI Motohiro
2009-07-28 1:53 ` Frederic Weisbecker
2009-07-28 2:19 ` Steven Rostedt
2009-08-17 9:22 ` [RFC PATCH] Add timer-source of walltime for ftrace Zhaolei
2009-08-17 16:49 ` Frederic Weisbecker
2009-08-18 2:09 ` Zhaolei
2009-08-18 18:52 ` Steven Rostedt
2009-08-18 15:57 ` KOSAKI Motohiro
2009-08-18 18:58 ` Steven Rostedt
2009-08-19 9:16 ` Zhaolei
2009-08-25 8:12 ` [PATCH 0/3] ftrace: " Zhaolei
2009-08-25 8:12 ` [PATCH 1/3] ftrace: Move setting of clock-source out of options Zhaolei
2009-08-26 2:35 ` Steven Rostedt
2009-08-26 7:23 ` [tip:tracing/core] " tip-bot for Zhaolei
2009-08-25 8:14 ` [PATCH 2/3] ftrace: add tracepoint for xtime Zhaolei
2009-08-26 2:39 ` Steven Rostedt
2009-09-01 8:03 ` Zhaolei
2009-09-16 19:56 ` john stultz
2009-09-16 19:58 ` john stultz
2009-09-16 20:32 ` Steven Rostedt
2009-09-16 20:49 ` john stultz
2009-09-17 6:34 ` Zhaolei
2009-08-25 8:15 ` [PATCH 3/3] ftrace: Add timer-source of walltime for ftrace Zhaolei
2009-08-26 2:52 ` Steven Rostedt
2009-09-16 5:25 ` [PATCH v2 0/2] " Zhaolei
2009-09-16 5:27 ` [PATCH v2 1/2] ftrace: add tracepoint for xtime Zhaolei
2009-09-16 19:33 ` Steven Rostedt
2009-09-16 5:29 ` [PATCH v2 2/2] ftrace: Add timer-source of walltime for ftrace Zhaolei
2009-09-16 5:59 ` Frederic Weisbecker
2009-09-16 6:40 ` Zhaolei
2009-09-16 19:37 ` Steven Rostedt
2009-09-17 7:10 ` Zhaolei
2009-11-04 9:39 ` [PATCH v3] ftrace: Add timer-source of walltime Zhaolei
2009-11-04 9:39 ` Zhaolei
2009-11-04 9:41 ` Zhaolei
2009-07-28 2:23 ` [PATCH 0/3] Add walltime support for ring-buffer KOSAKI Motohiro
2009-08-03 7:22 ` Ingo Molnar [this message]
2009-08-03 9:32 ` KOSAKI Motohiro
2009-08-04 14:38 ` Ingo Molnar
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