static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
{
	struct hw_perf_event *hwc = &event->hw;
	s64 period, sample_period;
	s64 delta;

	period = perf_calculate_period(event, nsec, count);

	delta = (s64)(period - hwc->sample_period);
	delta = (delta + 7) / 8; /* low pass filter */

	sample_period = hwc->sample_period + delta;

	if (!sample_period)
		sample_period = 1;

	hwc->sample_period = sample_period;

	if (local64_read(&hwc->period_left) > 8*sample_period) {
		if (disable)
			event->pmu->stop(event, PERF_EF_UPDATE);

		local64_set(&hwc->period_left, 0);

		if (disable)
			event->pmu->start(event, PERF_EF_RELOAD);
	}
}
static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
{
	struct hw_perf_event *hwc = &event->hw;
	s64 period, sample_period;
	s64 delta;

	period = perf_calculate_period(event, nsec, count);

	delta = (s64)(period - hwc->sample_period);
	delta = (delta + 7) / 8;  

	sample_period = hwc->sample_period + delta;

	if (!sample_period)
		sample_period = 1;

	hwc->sample_period = sample_period;

	if (local64_read(&hwc->period_left) > 8*sample_period) {
		if (disable)
			event->pmu->stop(event, PERF_EF_UPDATE);

		local64_set(&hwc->period_left, 0);

		if (disable)
			event->pmu->start(event, PERF_EF_RELOAD);
	}
}