Messages in this thread | | | Date | Tue, 21 Nov 2023 15:53:44 +0000 | From | Will Deacon <> | Subject | Re: [PATCH 07/34] perf/arm: optimize opencoded atomic find_bit() API |
| |
On Sat, Nov 18, 2023 at 07:50:38AM -0800, Yury Norov wrote: > Switch subsystem to use atomic find_bit() or atomic iterators as > appropriate. > > Signed-off-by: Yury Norov <yury.norov@gmail.com> > --- > drivers/perf/arm-cci.c | 23 +++++------------------ > drivers/perf/arm-ccn.c | 10 ++-------- > drivers/perf/arm_dmc620_pmu.c | 9 ++------- > drivers/perf/arm_pmuv3.c | 8 ++------ > 4 files changed, 11 insertions(+), 39 deletions(-) > > diff --git a/drivers/perf/arm-cci.c b/drivers/perf/arm-cci.c > index 61de861eaf91..70fbf9d09d37 100644 > --- a/drivers/perf/arm-cci.c > +++ b/drivers/perf/arm-cci.c > @@ -320,12 +320,8 @@ static int cci400_get_event_idx(struct cci_pmu *cci_pmu, > return CCI400_PMU_CYCLE_CNTR_IDX; > } > > - for (idx = CCI400_PMU_CNTR0_IDX; idx <= CCI_PMU_CNTR_LAST(cci_pmu); ++idx) > - if (!test_and_set_bit(idx, hw->used_mask)) > - return idx; > - > - /* No counters available */ > - return -EAGAIN; > + idx = find_and_set_bit(hw->used_mask, CCI_PMU_CNTR_LAST(cci_pmu) + 1);
CCI400_PMU_CNTR0_IDX is defined as 1, so isn't this wrong?
[...]
> diff --git a/drivers/perf/arm_dmc620_pmu.c b/drivers/perf/arm_dmc620_pmu.c > index 30cea6859574..e41c84dabc3e 100644 > --- a/drivers/perf/arm_dmc620_pmu.c > +++ b/drivers/perf/arm_dmc620_pmu.c > @@ -303,13 +303,8 @@ static int dmc620_get_event_idx(struct perf_event *event) > end_idx = DMC620_PMU_MAX_COUNTERS; > } > > - for (idx = start_idx; idx < end_idx; ++idx) { > - if (!test_and_set_bit(idx, dmc620_pmu->used_mask)) > - return idx; > - } > - > - /* The counters are all in use. */ > - return -EAGAIN; > + idx = find_and_set_next_bit(dmc620_pmu->used_mask, end_idx, start_idx);
It might just be me, but I'd find this a tonne easier to read if you swapped the last two arguments around so that the offset came before the limit in the new function.
Will
| |