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authorAdrian Hunter <adrian.hunter@intel.com>2013-08-27 11:23:07 +0300
committerArnaldo Carvalho de Melo <acme@redhat.com>2013-08-29 15:40:03 -0300
commitff3d527cebc1fa3707c617bfe9e74f53fcfb0955 (patch)
tree64181865fd8b48a2ea99d11724e79844c193b5cf /include
parentef89325f773bc9f2f4e6019bd7f3d968ba85df9a (diff)
perf: make events stream always parsable
The event stream is not always parsable because the format of a sample is dependent on the sample_type of the selected event. When there is more than one selected event and the sample_types are not the same then parsing becomes problematic. A sample can be matched to its selected event using the ID that is allocated when the event is opened. Unfortunately, to get the ID from the sample means first parsing it. This patch adds a new sample format bit PERF_SAMPLE_IDENTIFER that puts the ID at a fixed position so that the ID can be retrieved without parsing the sample. For sample events, that is the first position immediately after the header. For non-sample events, that is the last position. In this respect parsing samples requires that the sample_type and ID values are recorded. For example, perf tools records struct perf_event_attr and the IDs within the perf.data file. Those must be read first before it is possible to parse samples found later in the perf.data file. Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Tested-by: Stephane Eranian <eranian@google.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: David Ahern <dsahern@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Namhyung Kim <namhyung@gmail.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/r/1377591794-30553-6-git-send-email-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'include')
-rw-r--r--include/uapi/linux/perf_event.h27
1 files changed, 20 insertions, 7 deletions
diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
index 62c25a25291c..42cb7b62ca59 100644
--- a/include/uapi/linux/perf_event.h
+++ b/include/uapi/linux/perf_event.h
@@ -134,8 +134,9 @@ enum perf_event_sample_format {
PERF_SAMPLE_STACK_USER = 1U << 13,
PERF_SAMPLE_WEIGHT = 1U << 14,
PERF_SAMPLE_DATA_SRC = 1U << 15,
+ PERF_SAMPLE_IDENTIFIER = 1U << 16,
- PERF_SAMPLE_MAX = 1U << 16, /* non-ABI */
+ PERF_SAMPLE_MAX = 1U << 17, /* non-ABI */
};
/*
@@ -492,12 +493,12 @@ enum perf_event_type {
/*
* If perf_event_attr.sample_id_all is set then all event types will
* have the sample_type selected fields related to where/when
- * (identity) an event took place (TID, TIME, ID, CPU, STREAM_ID)
- * described in PERF_RECORD_SAMPLE below, it will be stashed just after
- * the perf_event_header and the fields already present for the existing
- * fields, i.e. at the end of the payload. That way a newer perf.data
- * file will be supported by older perf tools, with these new optional
- * fields being ignored.
+ * (identity) an event took place (TID, TIME, ID, STREAM_ID, CPU,
+ * IDENTIFIER) described in PERF_RECORD_SAMPLE below, it will be stashed
+ * just after the perf_event_header and the fields already present for
+ * the existing fields, i.e. at the end of the payload. That way a newer
+ * perf.data file will be supported by older perf tools, with these new
+ * optional fields being ignored.
*
* struct sample_id {
* { u32 pid, tid; } && PERF_SAMPLE_TID
@@ -505,7 +506,12 @@ enum perf_event_type {
* { u64 id; } && PERF_SAMPLE_ID
* { u64 stream_id;} && PERF_SAMPLE_STREAM_ID
* { u32 cpu, res; } && PERF_SAMPLE_CPU
+ * { u64 id; } && PERF_SAMPLE_IDENTIFIER
* } && perf_event_attr::sample_id_all
+ *
+ * Note that PERF_SAMPLE_IDENTIFIER duplicates PERF_SAMPLE_ID. The
+ * advantage of PERF_SAMPLE_IDENTIFIER is that its position is fixed
+ * relative to header.size.
*/
/*
@@ -594,6 +600,13 @@ enum perf_event_type {
* struct {
* struct perf_event_header header;
*
+ * #
+ * # Note that PERF_SAMPLE_IDENTIFIER duplicates PERF_SAMPLE_ID.
+ * # The advantage of PERF_SAMPLE_IDENTIFIER is that its position
+ * # is fixed relative to header.
+ * #
+ *
+ * { u64 id; } && PERF_SAMPLE_IDENTIFIER
* { u64 ip; } && PERF_SAMPLE_IP
* { u32 pid, tid; } && PERF_SAMPLE_TID
* { u64 time; } && PERF_SAMPLE_TIME