perf tools: Describe pipe mode in perf.data-file-fomat.txt (6d13491e) · Commits · 戴 / test

Add a minimal description of pipe's data format. Signed-off-by:

David Carrillo-Cisneros <davidcc@google.com> Acked-by:

Jiri Olsa <jolsa@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: He Kuang <hekuang@huawei.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paul Turner <pjt@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Simon Que <sque@chromium.org> Cc: Stephane Eranian <eranian@google.com> Cc: Wang Nan <wangnan0@huawei.com> Link: http://lkml.kernel.org/r/20170410201432.24807-4-davidcc@google.com Signed-off-by:

Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/Documentation/perf.data-file-format.txt

+17 −2

Original line number	Diff line number	Diff line
		@@ -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:

		@@ -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

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