Re: [RFC 2/2] perf: update userspace page info for software event

[Shaohua Li <shli@fb.com>]

Ping!

On Fri, Jan 23, 2015 at 07:57:24AM -0800, Shaohua Li wrote:
> On Fri, Jan 23, 2015 at 09:44:51AM +0100, Peter Zijlstra wrote:
> > On Thu, Jan 22, 2015 at 01:09:02PM -0800, Shaohua Li wrote:
> > > ---
> > >  kernel/events/core.c | 3 +++
> > >  1 file changed, 3 insertions(+)
> > > 
> > > diff --git a/kernel/events/core.c b/kernel/events/core.c
> > > index 4edde3e..4221240 100644
> > > --- a/kernel/events/core.c
> > > +++ b/kernel/events/core.c
> > > @@ -5950,6 +5950,7 @@ static int perf_swevent_add(struct perf_event *event, int flags)
> > >  	}
> > >  
> > >  	hlist_add_head_rcu(&event->hlist_entry, head);
> > > +	perf_event_update_userpage(event);
> > >  
> > >  	return 0;
> > >  }
> > > @@ -6419,6 +6420,7 @@ static int cpu_clock_event_add(struct perf_event *event, int flags)
> > >  {
> > >  	if (flags & PERF_EF_START)
> > >  		cpu_clock_event_start(event, flags);
> > > +	perf_event_update_userpage(event);
> > >  
> > >  	return 0;
> > >  }
> > > @@ -6493,6 +6495,7 @@ static int task_clock_event_add(struct perf_event *event, int flags)
> > >  {
> > >  	if (flags & PERF_EF_START)
> > >  		task_clock_event_start(event, flags);
> > > +	perf_event_update_userpage(event);
> > >  
> > >  	return 0;
> > >  }
> > 
> > How about the one I sent; which adds it to {start,stop} instead of add?
> > {start,stop} is the right place to add them, although this add might be
> > sufficient for your use case.
> Hi Peter,
> I tried {start, stop}, it doesn't work (doesn't get called in context
> switch) and I still get a CLOCK_MONOTONIC. So I added it to .add, which
> is called in context switch and I got correct thread time. Am I missing
> anything?
> 
> Thanks,
> Shaohua