(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 patch, it is possible to get: $ perf record -o - -e cycles -c 100000 sleep 1 | perf report --stdio [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.000 MB - ] # hostname : myhost # 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 Percent | Source code & Disassembly of kcore for cycles (9 samples) ... David Carrillo-Cisneros (7): perf header: fail on write_padded error perf util: add const modifier to buf in "writen" function perf header: use struct feat_fd for write perf header: use struct feat_fd for print perf header: use struct feat_fd for process and read perf tool: make show-info in perf report a tool attribute perf tools: add feature header record to pipe-mode tools/perf/builtin-annotate.c | 1 + tools/perf/builtin-inject.c | 1 + tools/perf/builtin-record.c | 6 + tools/perf/builtin-report.c | 6 +- tools/perf/builtin-script.c | 6 +- tools/perf/util/build-id.c | 10 +- tools/perf/util/build-id.h | 4 +- tools/perf/util/event.c | 13 + tools/perf/util/event.h | 19 + tools/perf/util/header.c | 905 +++++++++++++++++++++++------------------- tools/perf/util/header.h | 17 +- tools/perf/util/session.c | 12 + tools/perf/util/tool.h | 4 +- tools/perf/util/util.c | 6 +- tools/perf/util/util.h | 2 +- 15 files changed, 594 insertions(+), 418 deletions(-) -- 2.13.0.303.g4ebf302169-goog
