Messages in this thread | | | Date | Wed, 10 Jan 2018 11:22:49 +0100 | From | Jiri Olsa <> | Subject | Re: [RESEND PATCH V2 1/4] perf/x86/intel: fix event update for auto-reload |
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On Mon, Jan 08, 2018 at 07:15:13AM -0800, kan.liang@intel.com wrote:
SNIP
> There is nothing need to do in x86_perf_event_set_period(). Because it > is fixed period. The period_left is already adjusted. > > Signed-off-by: Kan Liang <kan.liang@linux.intel.com> > --- > arch/x86/events/intel/ds.c | 69 ++++++++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 67 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c > index 3674a4b..cc1f373 100644 > --- a/arch/x86/events/intel/ds.c > +++ b/arch/x86/events/intel/ds.c > @@ -1251,17 +1251,82 @@ get_next_pebs_record_by_bit(void *base, void *top, int bit) > return NULL; > } > > +/* > + * Specific intel_pmu_save_and_restart() for auto-reload. > + */ > +static int intel_pmu_save_and_restart_reload(struct perf_event *event, > + u64 reload_val, > + int reload_times) > +{ > + struct hw_perf_event *hwc = &event->hw; > + int shift = 64 - x86_pmu.cntval_bits; > + u64 prev_raw_count, new_raw_count; > + u64 delta; > + > + if ((reload_times == 0) || (reload_val == 0)) > + return intel_pmu_save_and_restart(event);
why is this check needed? AFAICS __intel_pmu_pebs_event is called only if reload_times != 0 and reload_val is always non zero for sampling
jirka
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