v2: - Finer patch splitting. - Add only one record type with a feature id instead of one record per new feature (as suggested by Jiri). - Add perf.data documentation.
(This is a rebased and updated version of Stephane Eranian's version in https://patchwork.kernel.org/patch/1499081/) Up until now, meta-data was only available when perf record was used in "regular" mode, i.e., generating a perf.data file. For users depending on pipe mode, neither host or event header information were gathered. This patch addresses this limitation. The difficulty in pipe mode is that information needs to be written sequentially to the pipe. Meta data headers are usually generated (and also expected) at the beginning of the file (or piped output). To solve this problem, we introduce new synthetic record types, one for each meta-data type. The approach is similar to what is *ALREADY* used for BUILD_ID and TRACING_DATA. We have modified util/header.c such that the same routines are used to generate and read the meta-data information regardless of pipe-mode vs. regular mode. To make this work, we added a new struct called feat_fd which encapsulates all the information necessary to read or write meta-data information to a file/pipe or from a file/pipe. With this series, it is possible to get: $ perf record -o - -e cycles sleep 1 | perf report --stdio --header # ======== # captured on: Mon May 22 16:33:43 2017 # ======== # # hostname : my_hostname # os release : 4.11.0-dbx-up_perf # perf version : 4.11.rc6.g6277c80 # arch : x86_64 # nrcpus online : 72 # nrcpus avail : 72 # cpudesc : Intel(R) Xeon(R) CPU E5-2696 v3 @ 2.30GHz # cpuid : GenuineIntel,6,63,2 # total memory : 263457192 kB # cmdline : /root/perf record -o - -e cycles -c 100000 sleep 1 # HEADER_CPU_TOPOLOGY info available, use -I to display # HEADER_NUMA_TOPOLOGY info available, use -I to display # pmu mappings: intel_bts = 6, uncore_imc_4 = 22, uncore_sbox_1 = 47, uncore_cbox_5 = 33, uncore_ha_0 = 16, uncore_cbox [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.000 MB - ] ... Only patch 13/13 has a significant effect in perf's behavior. All other are transparent preparatory changes or bug fixes. David Carrillo-Cisneros (13): perf header: encapsulate read and swap perf header: add PROCESS_STR_FUN macro perf header: fail on write_padded error perf util: add const modifier to buf in "writen" function perf header: revamp do_write perf header: add struct feat_fd for write perf header: use struct feat_fd for print perf header: use struct feat_fd to process header records perf header: use struct feat_fd in read header records perf header: add a buffer to struct feat_fd perf header: change FEAT_OP* macros perf tool: add show_feature_header to perf_tool perf tools: add feature header record to pipe-mode tools/perf/Documentation/perf.data-file-format.txt | 10 +- tools/perf/builtin-annotate.c | 1 + tools/perf/builtin-inject.c | 1 + tools/perf/builtin-record.c | 7 + tools/perf/builtin-report.c | 12 +- tools/perf/builtin-script.c | 4 + tools/perf/util/build-id.c | 10 +- tools/perf/util/build-id.h | 4 +- tools/perf/util/event.c | 1 + tools/perf/util/event.h | 8 + tools/perf/util/header.c | 877 +++++++++++---------- tools/perf/util/header.h | 16 +- tools/perf/util/session.c | 12 + tools/perf/util/tool.h | 10 +- tools/perf/util/util.c | 6 +- tools/perf/util/util.h | 2 +- 16 files changed, 564 insertions(+), 417 deletions(-) -- 2.13.0.219.gdb65acc882-goog