Messages in this thread | | | Date | Thu, 11 Jan 2018 11:54:46 +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 Wed, Jan 10, 2018 at 09:31:01AM -0500, Liang, Kan wrote: > > > On 1/10/2018 5:22 AM, Jiri Olsa wrote: > > 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 > > > > Here is a sanity check for reload_times and reload_val. > Right, usually they are non zero. > I think it should not bring any issues. Right? > If so, I think we may still keep it?
sure, no big deal.. I just don't see the reason ;-)
jirka
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