Re: [REPOST PATCH] ftrace: Remove the unused variant ftrace_update_time

From: Minfei Huang
Date: Tue Sep 15 2015 - 12:33:18 EST


On 09/15/15 at 12:12pm, Steven Rostedt wrote:
> On Wed, 16 Sep 2015 00:00:46 +0800
> Minfei Huang <mnfhuang@xxxxxxxxx> wrote:
>
> > On 09/15/15 at 11:50am, Steven Rostedt wrote:
> > > On Tue, 15 Sep 2015 23:37:39 +0800
> > > Minfei Huang <mnfhuang@xxxxxxxxx> wrote:
> > >
> > >
> > > > I think the variant ftrace_update_time is not used any more. Previously,
> > > > it is used to print the time how long ftrace will spend to update the
> > > > code in fucntion ftraced.
> > >
> > > Yes, I know what it measures. It's been on my todo list to export that
> > > out to userspace, as it is an interesting metric.
> > >
> >
> > Export the time which ftrace spent to update the all of the function?
> > How about exporting the time ftrace spent in latest time?
> >
>
> I think you misunderstood me. I want to export what it is now. The time
> it took to run ftrace_update_code() the last time it ran. Not a total
> amount of time that it ran for.
>

Got it.

There is one more confusion. Is it valuable to export such info to
userspace? What does user do, if kernel exports this?

Thanks
Minfei
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