On Tue, Dec 19, 2017 at 03:08:58PM -0500, Liang, Kan wrote: > > This all looks very wrong... In auto reload we should never call > > intel_pmu_save_and_restore() in the first place I think. > > > > Things like x86_perf_event_update() and x86_perf_event_set_period() > > simply _cannot_ do the right thing when we auto reload the counter. > > > > I think it should be OK to call it in first place. > For x86_perf_event_update(), the reload_times will tell if it's auto reload. > Both period_left and event->count are carefully recalculated for auto > reload.
How does prev_count make sense when we've already reloaded a bunch of times? > For x86_perf_event_set_period(), there is nothing special needed for auto > reload. The period is fixed. The period_left from x86_perf_event_update() is > already handled. Hurm.. I see. But rather than make an ever bigger trainwreck of things, I'd rather you just write a special purpose intel_pmu_save_and_restart() just for AUTO_RELOAD.
