Messages in this thread | | | Date | Thu, 10 Jun 2010 18:26:04 +0200 | From | Frederic Weisbecker <> | Subject | Re: [PATCH 3/5] perf: New PERF_EVENT_STATE_PAUSED event state |
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On Thu, Jun 10, 2010 at 12:55:17PM +0200, Peter Zijlstra wrote: > On Thu, 2010-06-10 at 05:49 +0200, Frederic Weisbecker wrote: > > This brings a new PERF_EVENT_STATE_PAUSED state. It means the events > > is enabled but we don't want it to run, it must be in the same state > > than after a pmu->stop() call. So the event has been reserved and > > allocated and it is ready to start after a pmu->start() call. > > > > It is deemed for hardware events when we want them to be reserved on > > the cpu and ready to be started anytime. This is going to be useful > > for the new context exclusion that will follow. > > > > Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> > > Cc: Ingo Molnar <mingo@elte.hu> > > Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> > > Cc: Arnaldo Carvalho de Melo <acme@redhat.com> > > Cc: Paul Mackerras <paulus@samba.org> > > Cc: Stephane Eranian <eranian@google.com> > > Cc: Cyrill Gorcunov <gorcunov@gmail.com> > > Cc: Zhang Yanmin <yanmin_zhang@linux.intel.com> > > Cc: Steven Rostedt <rostedt@goodmis.org> > > --- > > arch/x86/kernel/cpu/perf_event.c | 6 ++++-- > > include/linux/perf_event.h | 3 ++- > > kernel/perf_event.c | 7 ++++--- > > 3 files changed, 10 insertions(+), 6 deletions(-) > > > > diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c > > index f2da20f..9b0e52f 100644 > > --- a/arch/x86/kernel/cpu/perf_event.c > > +++ b/arch/x86/kernel/cpu/perf_event.c > > @@ -839,7 +839,8 @@ void hw_perf_enable(void) > > match_prev_assignment(hwc, cpuc, i)) > > continue; > > > > - x86_pmu_stop(event); > > + if (event->state != PERF_EVENT_STATE_PAUSED) > > + x86_pmu_stop(event); > > } > > > > for (i = 0; i < cpuc->n_events; i++) { > > @@ -851,7 +852,8 @@ void hw_perf_enable(void) > > else if (i < n_running) > > continue; > > > > - x86_pmu_start(event); > > + if (event->state != PERF_EVENT_STATE_PAUSED) > > + x86_pmu_start(event); > > } > > cpuc->n_added = 0; > > perf_events_lapic_init(); > > Also, I'd rather keep the whole event->state knowledge in the generic > code.
Yeah, but if we do this, we need to maintain the exact same state in the arch level. We need this for every pmus.
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