From: Peter Zijlstra <peterz@infradead.org>
To: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Cc: Ingo Molnar <mingo@elte.hu>, Thomas Gleixner <tglx@linutronix.de>,
Steven Rostedt <rostedt@goodmis.org>,
Frederic Weisbecker <fweisbec@gmail.com>,
Zhaolei <zhaolei@cn.fujitsu.com>,
kosaki.motohiro@jp.fujitsu.com,
Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>,
Anton Blanchard <anton@samba.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3 3/4] ftrace: add tracepoint for hrtimer
Date: Thu, 23 Jul 2009 12:07:41 +0200 [thread overview]
Message-ID: <1248343661.27058.1722.camel@twins> (raw)
In-Reply-To: <4A6834EA.3070303@cn.fujitsu.com>
On Thu, 2009-07-23 at 18:01 +0800, Xiao Guangrong wrote:
>
> Peter Zijlstra wrote:
>
> > OK, so what you want to measure is the time of the actual callback
> > happening (hrtimer_entry) vs that where you would have expected it to
> > happen (hrtimer_start + delay), right?
> >
>
> Yes
>
> > So what's wrong with printing the expected expiration time in the
> > hrtimer_start tracepoint in the cheap clock units?
> >
>
> Is "cheap clock units" means jiffies time?
Nah, something like cpu_clock() which is monotonic per-cpu and should
have high resolution where available.
next prev parent reply other threads:[~2009-07-23 10:06 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-07-17 10:11 [PATCH v3 0/4] ftrace: add tracepoint for timer event Xiao Guangrong
2009-07-17 10:14 ` [PATCH v3 1/4] tracing/events: Add timer and high res timer tracepoints Xiao Guangrong
2009-07-17 10:16 ` [PATCH v3 2/4] ftrace: add tracepoint for timer Xiao Guangrong
2009-07-17 10:18 ` [PATCH v3 3/4] ftrace: add tracepoint for hrtimer Xiao Guangrong
2009-07-17 10:50 ` Peter Zijlstra
2009-07-20 7:25 ` Xiao Guangrong
2009-07-20 12:09 ` Peter Zijlstra
2009-07-22 9:36 ` Xiao Guangrong
2009-07-22 10:13 ` Peter Zijlstra
2009-07-22 15:36 ` Mathieu Desnoyers
2009-07-23 10:01 ` Xiao Guangrong
2009-07-23 10:07 ` Peter Zijlstra [this message]
2009-07-24 9:40 ` Xiao Guangrong
2009-07-24 11:11 ` Peter Zijlstra
2009-07-17 10:20 ` [PATCH v3 4/4] ftrace: add tracepoint for itimer Xiao Guangrong
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