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linux/tools
Namhyung Kim bdd051e249 perf record: Split --data-mmap option
Currently -d/--data option controls both PERF_SAMPLE_ADDR bit and
perf_event_attr.mmap_data flag.  Separate them using new --data-mmap
option to support recording only one of them.

For data-type profiling, data MMAP is unnecessary but it wastes a lot
of space in the ring buffer and data file.

Committer testing:

On an idle system:

  root@x1:~# perf record -d -a sleep 1
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 5.672 MB perf.data (1075 samples) ]
  root@x1:~# ls -la perf.data
  -rw-------. 1 root root 5982480 Dec 16 15:34 perf.data
  root@x1:~# perf evlist -v
  cpu_atom/cycles/P: type: 0 (PERF_TYPE_HARDWARE), size: 144, config: 0xa00000000 (cpu_atom/PERF_COUNT_HW_CPU_CYCLES/), { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|ADDR|CPU|PERIOD|IDENTIFIER|DATA_SRC, read_format: ID|LOST, disabled: 1, freq: 1, precise_ip: 3, sample_id_all: 1
  cpu_core/cycles/P: type: 0 (PERF_TYPE_HARDWARE), size: 144, config: 0x400000000 (cpu_core/PERF_COUNT_HW_CPU_CYCLES/), { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|ADDR|CPU|PERIOD|IDENTIFIER|DATA_SRC, read_format: ID|LOST, disabled: 1, freq: 1, precise_ip: 3, sample_id_all: 1
  dummy:u: type: 1 (PERF_TYPE_SOFTWARE), size: 144, config: 0x9 (PERF_COUNT_SW_DUMMY), { sample_period, sample_freq }: 1, sample_type: IP|TID|TIME|ADDR|CPU|IDENTIFIER|DATA_SRC, read_format: ID|LOST, exclude_kernel: 1, exclude_hv: 1, mmap: 1, comm: 1, task: 1, mmap_data: 1, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1, ksymbol: 1, bpf_event: 1, build_id: 1
  root@x1:~#

Now with just --data-mmap we will not save that much, as only DATA_SRC
will not be enabled in sample_type:

  root@x1:~# perf record --data-mmap -a sleep 1
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 5.576 MB perf.data (716 samples) ]
  root@x1:~# ls -la perf.data
  -rw-------. 1 root root 5880112 Dec 16 15:37 perf.data
  root@x1:~# perf evlist -v
  cpu_atom/cycles/P: type: 0 (PERF_TYPE_HARDWARE), size: 144, config: 0xa00000000 (cpu_atom/PERF_COUNT_HW_CPU_CYCLES/), { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|CPU|PERIOD|IDENTIFIER, read_format: ID|LOST, disabled: 1, freq: 1, precise_ip: 3, sample_id_all: 1
  cpu_core/cycles/P: type: 0 (PERF_TYPE_HARDWARE), size: 144, config: 0x400000000 (cpu_core/PERF_COUNT_HW_CPU_CYCLES/), { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|CPU|PERIOD|IDENTIFIER, read_format: ID|LOST, disabled: 1, freq: 1, precise_ip: 3, sample_id_all: 1
  dummy:u: type: 1 (PERF_TYPE_SOFTWARE), size: 144, config: 0x9 (PERF_COUNT_SW_DUMMY), { sample_period, sample_freq }: 1, sample_type: IP|TID|TIME|CPU|IDENTIFIER, read_format: ID|LOST, exclude_kernel: 1, exclude_hv: 1, mmap: 1, comm: 1, task: 1, mmap_data: 1, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1, ksymbol: 1, bpf_event: 1, build_id: 1
  root@x1:~#

To complete, just with DATA_SRC, no mmap_data:

  root@x1:~# perf record --sample-mem-info -a sleep 1
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 1.407 MB perf.data (1311 samples) ]
  root@x1:~# ls -la perf.data
  -rw-------. 1 root root 1509224 Dec 16 15:40 perf.data
  root@x1:~# perf evlist -v
  cpu_atom/cycles/P: type: 0 (PERF_TYPE_HARDWARE), size: 144, config: 0xa00000000 (cpu_atom/PERF_COUNT_HW_CPU_CYCLES/), { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|CPU|PERIOD|IDENTIFIER|DATA_SRC, read_format: ID|LOST, disabled: 1, freq: 1, precise_ip: 3, sample_id_all: 1
  cpu_core/cycles/P: type: 0 (PERF_TYPE_HARDWARE), size: 144, config: 0x400000000 (cpu_core/PERF_COUNT_HW_CPU_CYCLES/), { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|CPU|PERIOD|IDENTIFIER|DATA_SRC, read_format: ID|LOST, disabled: 1, freq: 1, precise_ip: 3, sample_id_all: 1
  dummy:u: type: 1 (PERF_TYPE_SOFTWARE), size: 144, config: 0x9 (PERF_COUNT_SW_DUMMY), { sample_period, sample_freq }: 1, sample_type: IP|TID|TIME|CPU|IDENTIFIER|DATA_SRC, read_format: ID|LOST, exclude_kernel: 1, exclude_hv: 1, mmap: 1, comm: 1, task: 1, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1, ksymbol: 1, bpf_event: 1, build_id: 1
  root@x1:~#

Reviewed-by: Ian Rogers <irogers@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: James Clark <james.clark@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2025-12-17 09:30:37 -03:00
..
2025-07-23 11:55:22 +02:00
2025-07-28 16:47:35 -04:00