diff options
Diffstat (limited to 'tools/perf/Documentation/perf.data-file-format.txt')
| -rw-r--r-- | tools/perf/Documentation/perf.data-file-format.txt | 23 |
1 files changed, 19 insertions, 4 deletions
diff --git a/tools/perf/Documentation/perf.data-file-format.txt b/tools/perf/Documentation/perf.data-file-format.txt index b664b18d3991..de8b39dda7b8 100644 --- a/tools/perf/Documentation/perf.data-file-format.txt +++ b/tools/perf/Documentation/perf.data-file-format.txt @@ -11,8 +11,8 @@ All fields are in native-endian of the machine that generated the perf.data. When perf is writing to a pipe it uses a special version of the file format that does not rely on seeking to adjust data offsets. This -format is not described here. The pipe version can be converted to -normal perf.data with perf inject. +format is described in "Pipe-mode data" section. The pipe data version can be +augmented with additional events using perf inject. The file starts with a perf_header: @@ -270,7 +270,7 @@ When the event stream contains multiple events each event is identified by an ID. This can be either through the PERF_SAMPLE_ID or the PERF_SAMPLE_IDENTIFIER header. The PERF_SAMPLE_IDENTIFIER header is at a fixed offset from the event header, which allows reliable -parsing of the header. Relying on ID may be ambigious. +parsing of the header. Relying on ID may be ambiguous. IDENTIFIER is only supported by newer Linux kernels. Perf record specific events: @@ -288,7 +288,7 @@ struct attr_event { uint64_t id[]; }; - PERF_RECORD_HEADER_EVENT_TYPE = 65, /* depreceated */ + PERF_RECORD_HEADER_EVENT_TYPE = 65, /* deprecated */ #define MAX_EVENT_NAME 64 @@ -411,6 +411,21 @@ An array bound by the perf_file_section size. ids points to a array of uint64_t defining the ids for event attr attr. +Pipe-mode data + +Pipe-mode avoid seeks in the file by removing the perf_file_section and flags +from the struct perf_header. The trimmed header is: + +struct perf_pipe_file_header { + u64 magic; + u64 size; +}; + +The information about attrs, data, and event_types is instead in the +synthesized events PERF_RECORD_ATTR, PERF_RECORD_HEADER_TRACING_DATA and +PERF_RECORD_HEADER_EVENT_TYPE that are generated by perf record in pipe-mode. + + References: include/uapi/linux/perf_event.h |
