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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 /kernel
parentef89325f773bc9f2f4e6019bd7f3d968ba85df9a (diff)
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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 'kernel')
-rw-r--r--kernel/events/core.c11
1 files changed, 10 insertions, 1 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 928fae7..15d0f24 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -1213,6 +1213,9 @@ static void perf_event__id_header_size(struct perf_event *event)
if (sample_type & PERF_SAMPLE_TIME)
size += sizeof(data->time);
+ if (sample_type & PERF_SAMPLE_IDENTIFIER)
+ size += sizeof(data->id);
+
if (sample_type & PERF_SAMPLE_ID)
size += sizeof(data->id);
@@ -4280,7 +4283,7 @@ static void __perf_event_header__init_id(struct perf_event_header *header,
if (sample_type & PERF_SAMPLE_TIME)
data->time = perf_clock();
- if (sample_type & PERF_SAMPLE_ID)
+ if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
data->id = primary_event_id(event);
if (sample_type & PERF_SAMPLE_STREAM_ID)
@@ -4319,6 +4322,9 @@ static void __perf_event__output_id_sample(struct perf_output_handle *handle,
if (sample_type & PERF_SAMPLE_CPU)
perf_output_put(handle, data->cpu_entry);
+
+ if (sample_type & PERF_SAMPLE_IDENTIFIER)
+ perf_output_put(handle, data->id);
}
void perf_event__output_id_sample(struct perf_event *event,
@@ -4432,6 +4438,9 @@ void perf_output_sample(struct perf_output_handle *handle,
perf_output_put(handle, *header);
+ if (sample_type & PERF_SAMPLE_IDENTIFIER)
+ perf_output_put(handle, data->id);
+
if (sample_type & PERF_SAMPLE_IP)
perf_output_put(handle, data->ip);