Re: [PATCH v5 1/2] perf/core: Fix small negative period being ignored

On Sat, Aug 31, 2024 at 07:43:15AM +0000, Luo Gengkun wrote:

kernel/events/core.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c index c973e3c11e03..a9395bbfd4aa 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -4092,7 +4092,11 @@ static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bo period = perf_calculate_period(event, nsec, count); delta = (s64)(period - hwc->sample_period);

• delta = (delta + 7) / 8; /* low pass filter */

• if (delta >= 0)

• delta += 7;
  

• else

• delta -= 7;
  

• delta /= 8; /* low pass filter */

sample_period = hwc->sample_period + delta;

OK, that makes sense, Thanks!