From: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>,
todd.e.brandt@linux.intel.com, linux-pm@vger.kernel.org,
rafael.j.wysocki@intel.com
Subject: Re: [PATCH] PM: trace events for suspend/resume
Date: Fri, 23 May 2014 12:06:23 +0530 [thread overview]
Message-ID: <537EEC67.9030909@linux.vnet.ibm.com> (raw)
In-Reply-To: <1400798669.26671.12.camel@pippen.local.home>
On 05/23/2014 04:14 AM, Steven Rostedt wrote:
> On Fri, 2014-05-23 at 03:46 +0530, Srivatsa S. Bhat wrote:
>> Hi Todd,
>>
>> This might be a silly question, but the suspend_enter() function invokes
>> ftrace_stop() before suspending the machine, and restarts ftrace after
>> resume. And your patch seems to instrument code further down (deeper)
>> in the suspend/resume path (such as disable_nonboot_cpus() for example).
>> Doesn't the ftrace stop/start pose any problem for this patch?
>
> ftrace_start/stop() only affects the function tracer and not the
> tracepoints. Those will still be recorded.
>
Ah, thank you for the clarification.
> Note, we have an invested interest in getting rid of
> ftrace_stop/start(). I rather mark all the suspend code with notrace or
> find another method to protect suspend from function tracing. The
> ftrace_stop/start() was more of a big hammer approach and I had plans
> for getting rid of it in the future. That future is approaching fast :-)
>
Ok.. :-)
Regards,
Srivatsa S. Bhat
next prev parent reply other threads:[~2014-05-23 6:37 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-19 23:02 [PATCH] PM: trace events for suspend/resume Todd E Brandt
2014-05-22 0:01 ` Rafael J. Wysocki
2014-05-22 17:07 ` Todd E Brandt
2014-05-22 22:41 ` Steven Rostedt
2014-05-22 23:06 ` Rafael J. Wysocki
2014-05-30 14:49 ` Todd E Brandt
2014-05-22 22:16 ` Srivatsa S. Bhat
2014-05-22 22:44 ` Steven Rostedt
2014-05-23 6:36 ` Srivatsa S. Bhat [this message]
2014-05-22 23:50 ` Todd E Brandt
2014-05-23 6:37 ` Srivatsa S. Bhat
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