Re: [PATCH 3/9] PM: suspend_block: Abort task freezing if a suspend_blocker is active.

Nigel Cunningham
2009-05-09T00:12:23Z

Hi.

On Sat, 2009-05-09 at 01:01 +0200, Rafael J. Wysocki wrote:
> On Saturday 09 May 2009, Nigel Cunningham wrote:
> > Hi.
> >
> > On Fri, 2009-05-08 at 16:40 +0200, Rafael J. Wysocki wrote:
> > > The timeout is actually a workaround for the problem that we don't
> > > really
> > > know if tasks are going to react to our freeze requests and how much time it is
> > > going to take. The current value of 20 s was chosen after a number of
> > > experiments showing that in some cases the freezing _was_ going to take so
> > > much time. Of course the question is whether it makes sense to give up earlier
> > > even if tasks would eventually freeze, but that's a different issue.
> >
> > What were the circumstances in which freezing could take 20s?
>
> Compiling the kernel with "make -j " on a dual core system IIRC.
>
> Generally, the situation in which there are many runnable tasks and new tasks
> come and go etc. I haven't repeated this benchmark recently, though, so it's
> probably worth doing again.
>
> Which has a little to do with the $subject patch IMO, because I think that
> it's reasonable to stop freezing tasks as soon as we know that it won't be
> necessary anyway.

Yes, but it's still good to know.

Regards,

Nigel