| Date | Fri, 11 Feb 2022 10:30:37 +0000 | From | Mark Rutland <> | Subject | Re: [PATCH 33/49] perf: replace bitmap_weight with bitmap_weight_eq for ThunderX2 |
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On Thu, Feb 10, 2022 at 02:49:17PM -0800, Yury Norov wrote: > tx2_uncore_event_start() calls bitmap_weight() to compare the weight > of bitmap with a given number. We can do it more efficiently with > bitmap_weight_eq because conditional bitmap_weight may stop traversing > the bitmap earlier, as soon as condition is (or can't be) met. > > Signed-off-by: Yury Norov <yury.norov@gmail.com>
Given the max counters value is either 4 or 8 I doubt this should matter, but for consistenct this is fine, so:
Acked-by: Mark Rutland <mark.rutland@arm.com>
I now see bitmap_weight_eq() is introduced within this series, so I assume you need to queue that and its users together, and will want to take the prior drivers/perf/ bit together with that.
Thanks, Mark.
> --- > drivers/perf/thunderx2_pmu.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/perf/thunderx2_pmu.c b/drivers/perf/thunderx2_pmu.c > index 1edb9c03704f..97d5b39778fa 100644 > --- a/drivers/perf/thunderx2_pmu.c > +++ b/drivers/perf/thunderx2_pmu.c > @@ -623,8 +623,8 @@ static void tx2_uncore_event_start(struct perf_event *event, int flags) > return; > > /* Start timer for first event */ > - if (bitmap_weight(tx2_pmu->active_counters, > - tx2_pmu->max_counters) == 1) { > + if (bitmap_weight_eq(tx2_pmu->active_counters, > + tx2_pmu->max_counters, 1)) { > hrtimer_start(&tx2_pmu->hrtimer, > ns_to_ktime(tx2_pmu->hrtimer_interval), > HRTIMER_MODE_REL_PINNED); > -- > 2.32.0 >
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