From 7f453c24b95a085fc7bd35d53b33abc4dc5a048b Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 21 Jul 2009 13:19:40 +0200 Subject: perf_counter: PERF_SAMPLE_ID and inherited counters Anton noted that for inherited counters the counter-id as provided by PERF_SAMPLE_ID isn't mappable to the id found through PERF_RECORD_ID because each inherited counter gets its own id. His suggestion was to always return the parent counter id, since that is the primary counter id as exposed. However, these inherited counters have a unique identifier so that events like PERF_EVENT_PERIOD and PERF_EVENT_THROTTLE can be specific about which counter gets modified, which is important when trying to normalize the sample streams. This patch removes PERF_EVENT_PERIOD in favour of PERF_SAMPLE_PERIOD, which is more useful anyway, since changing periods became a lot more common than initially thought -- rendering PERF_EVENT_PERIOD the less useful solution (also, PERF_SAMPLE_PERIOD reports the more accurate value, since it reports the value used to trigger the overflow, whereas PERF_EVENT_PERIOD simply reports the requested period changed, which might only take effect on the next cycle). This still leaves us PERF_EVENT_THROTTLE to consider, but since that _should_ be a rare occurrence, and linking it to a primary id is the most useful bit to diagnose the problem, we introduce a PERF_SAMPLE_STREAM_ID, for those few cases where the full reconstruction is important. [Does change the ABI a little, but I see no other way out] Suggested-by: Anton Blanchard Signed-off-by: Peter Zijlstra LKML-Reference: <1248095846.15751.8781.camel@twins> --- include/linux/perf_counter.h | 15 ++++----------- 1 file changed, 4 insertions(+), 11 deletions(-) (limited to 'include') diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h index 5e970c7d3fd5..bd15d7a5f5ce 100644 --- a/include/linux/perf_counter.h +++ b/include/linux/perf_counter.h @@ -120,8 +120,9 @@ enum perf_counter_sample_format { PERF_SAMPLE_ID = 1U << 6, PERF_SAMPLE_CPU = 1U << 7, PERF_SAMPLE_PERIOD = 1U << 8, + PERF_SAMPLE_STREAM_ID = 1U << 9, - PERF_SAMPLE_MAX = 1U << 9, /* non-ABI */ + PERF_SAMPLE_MAX = 1U << 10, /* non-ABI */ }; /* @@ -312,16 +313,7 @@ enum perf_event_type { * struct perf_event_header header; * u64 time; * u64 id; - * u64 sample_period; - * }; - */ - PERF_EVENT_PERIOD = 4, - - /* - * struct { - * struct perf_event_header header; - * u64 time; - * u64 id; + * u64 stream_id; * }; */ PERF_EVENT_THROTTLE = 5, @@ -356,6 +348,7 @@ enum perf_event_type { * { u64 time; } && PERF_SAMPLE_TIME * { u64 addr; } && PERF_SAMPLE_ADDR * { u64 id; } && PERF_SAMPLE_ID + * { u64 stream_id;} && PERF_SAMPLE_STREAM_ID * { u32 cpu, res; } && PERF_SAMPLE_CPU * { u64 period; } && PERF_SAMPLE_PERIOD * -- cgit v1.2.3