From abd50713944c8ea9e0af5b7bffa0aacae21cc91a Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 26 Jan 2010 18:50:16 +0100 Subject: perf: Reimplement frequency driven sampling There was a bug in the old period code that caused intel_pmu_enable_all() or native_write_msr_safe() to show up quite high in the profiles. In staring at that code it made my head hurt, so I rewrote it in a hopefully simpler fashion. Its now fully symetric between tick and overflow driven adjustments and uses less data to boot. The only complication is that it basically wants to do a u128 division. The code approximates that in a rather simple truncate until it fits fashion, taking care to balance the terms while truncating. This version does not generate that sampling artefact. Signed-off-by: Peter Zijlstra LKML-Reference: Cc: Signed-off-by: Ingo Molnar --- include/linux/perf_event.h | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'include') diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index c6f812e4d05..72b2615600d 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -498,9 +498,8 @@ struct hw_perf_event { atomic64_t period_left; u64 interrupts; - u64 freq_count; - u64 freq_interrupts; - u64 freq_stamp; + u64 freq_time_stamp; + u64 freq_count_stamp; #endif }; -- cgit v1.2.3