add_sample
add_sample(&pmu->sample[I915_SAMPLE_WAIT], period_ns);
add_sample(&pmu->sample[I915_SAMPLE_SEMA], period_ns);
add_sample(&pmu->sample[I915_SAMPLE_BUSY], period_ns);
add_sample(&pmu->sample[I915_SAMPLE_WAIT], period_ns);
add_sample(&pmu->sample[I915_SAMPLE_BUSY], period_ns);