Re: [PATCH] perf/x86/uncore: Allow single pmu/box within events group

[Jiri Olsa]

On Fri, Nov 18, 2016 at 01:53:54PM +0100, Peter Zijlstra wrote:
> On Fri, Nov 18, 2016 at 01:33:25PM +0100, Jiri Olsa wrote:
> > On Fri, Nov 18, 2016 at 12:28:50PM +0100, Peter Zijlstra wrote:
> > > On Fri, Nov 18, 2016 at 01:15:28AM +0100, Jiri Olsa wrote:
> > > > Current uncore_validate_group code expects all events within
> > > > the group to have same pmu.
> > > > 
> > > > This leads to constraint code using wrong boxes which leads
> > > > in my case to touching uninitialized spinlocks, but could
> > > > be probably worse.. depends on type and box details.
> > > > 
> > > > I get lockdep warning below for following perf stat:
> > > >   # perf stat -vv -e '{uncore_cbox_0/config=0x0334/,uncore_qpi_0/event=1/}' -a sleep 1
> > > 
> > > Hurm, we shouldn't be allowing that in the first place I think.
> > > 
> > > 
> > > Let me stare at the generic group code, the intent was to only allow
> > > software events to mix with hw events, nothing else.
> > 
> > yep, that's what's happening now.. but after the event_init callback
> 
> Ah yes indeed. Its the is_uncore_event() test in uncore_collect_event()
> that's too lenient, that allows us to mix events from various uncore
> boxes.
> 
> Would something like so fix things too? Because that is the point of
> is_uncore_event() in collect(), to only collect events for _that_ pmu.

that looks ok.. I'll run the test 

jirka