On Mon, 2009-11-23 at 14:34 +0100, stephane eranian wrote:
> > Won't this give very funny results for mixed pmu groups?
> >
>
> What do you mean by 'mixed pmu groups'?
We currently have a number of struct pmu objects:
perf_ops_generic
perf_ops_cpu_clock
perf_ops_task_clock
which are all software based PMUs, and one of:
pmu (arch/x86/kernel/cpu/perf_event.c)
power_pmu (arch/powerpc/kernel/perf_event.c)
To represent the hardware PMU.
Now say you mix software events and hardware events into a single group,
the loop in validate_group:
list_for_each_entry(sibling, &leader->sibling_list, group_entry) {
if (!validate_event(&fake_pmu, sibling))
return -ENOSPC;
}
could pass a !hardware event into validate_event(), which currently
ignores it because event->pmu won't be &pmu, however if you remove that
check, it'll try and call x86 routines on a software event, which is
bound to go funny.
Now Frederic is going to make things more interesting by representing HW
breakpoints as another HW PMU (the distinction between hw/sw pmu is in
scheduling, you can always schedule a software event).
This weakens the !is_software_event(), in that !software doesn't tell
you which hardware event it is -- something which needs mending in your
more complex x86 constraints scheduling patch.
------------------------------------------------------------------------------
Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day
trial. Simplify your report design, integration and deployment - and focus on
what you do best, core application coding. Discover what's new with
Crystal Reports now. http://p.sf.net/sfu/bobj-july
_______________________________________________
perfmon2-devel mailing list
perfmon2-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/perfmon2-devel
