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| author | Peter Zijlstra <peterz@infradead.org> | 2010-04-08 23:03:20 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2010-05-07 11:31:02 +0200 |
| commit | ab608344bcbde4f55ec4cd911b686b0ce3eae076 (patch) | |
| tree | ebd38efabfaab59d6de11a24143d70e1eec36fae /include/linux/perf_event.h | |
| parent | 2b0b5c6fe9b383f3cf35a0a6371c9d577bd523ff (diff) | |
| download | lwn-ab608344bcbde4f55ec4cd911b686b0ce3eae076.tar.gz lwn-ab608344bcbde4f55ec4cd911b686b0ce3eae076.zip | |
perf, x86: Improve the PEBS ABI
Rename perf_event_attr::precise to perf_event_attr::precise_ip and
widen it to 2 bits. This new field describes the required precision of
the PERF_SAMPLE_IP field:
0 - SAMPLE_IP can have arbitrary skid
1 - SAMPLE_IP must have constant skid
2 - SAMPLE_IP requested to have 0 skid
3 - SAMPLE_IP must have 0 skid
And modify the Intel PEBS code accordingly. The PEBS implementation
now supports up to precise_ip == 2, where we perform the IP fixup.
Also s/PERF_RECORD_MISC_EXACT/&_IP/ to clarify its meaning, this bit
should be set for each PERF_SAMPLE_IP field known to match the actual
instruction triggering the event.
This new scheme allows for a PEBS mode that uses the buffer for more
than a single event.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stephane Eranian <eranian@google.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'include/linux/perf_event.h')
| -rw-r--r-- | include/linux/perf_event.h | 23 |
1 files changed, 19 insertions, 4 deletions
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 6be4a0f9137c..23cd0057a681 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -203,9 +203,19 @@ struct perf_event_attr { enable_on_exec : 1, /* next exec enables */ task : 1, /* trace fork/exit */ watermark : 1, /* wakeup_watermark */ - precise : 1, /* OoO invariant counter */ - - __reserved_1 : 48; + /* + * precise_ip: + * + * 0 - SAMPLE_IP can have arbitrary skid + * 1 - SAMPLE_IP must have constant skid + * 2 - SAMPLE_IP requested to have 0 skid + * 3 - SAMPLE_IP must have 0 skid + * + * See also PERF_RECORD_MISC_EXACT_IP + */ + precise_ip : 2, /* skid constraint */ + + __reserved_1 : 47; union { __u32 wakeup_events; /* wakeup every n events */ @@ -296,7 +306,12 @@ struct perf_event_mmap_page { #define PERF_RECORD_MISC_GUEST_KERNEL (4 << 0) #define PERF_RECORD_MISC_GUEST_USER (5 << 0) -#define PERF_RECORD_MISC_EXACT (1 << 14) +/* + * Indicates that the content of PERF_SAMPLE_IP points to + * the actual instruction that triggered the event. See also + * perf_event_attr::precise_ip. + */ +#define PERF_RECORD_MISC_EXACT_IP (1 << 14) /* * Reserve the last bit to indicate some extended misc field */ |