Commit cf99ad14 authored by Andi Kleen's avatar Andi Kleen Committed by Arnaldo Carvalho de Melo

perf record: Support weak groups

Implement a weak group fallback for 'perf record', similar to the
existing 'perf stat' support.  This allows to use groups that might be
longer than the available counters without failing.


  $ perf record  -e '{cycles,cache-misses,cache-references,cpu_clk_unhalted.thread,cycles,cycles,cycles}' -a sleep 1
  The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (cycles).
  /bin/dmesg | grep -i perf may provide additional information.


  $ ./perf record  -e '{cycles,cache-misses,cache-references,cpu_clk_unhalted.thread,cycles,cycles,cycles}:W' -a sleep 1
  WARNING: No sample_id_all support, falling back to unordered processing
  [ perf record: Woken up 3 times to write data ]
  [ perf record: Captured and wrote 8.136 MB (134069 samples) ]
Signed-off-by: default avatarAndi Kleen <>
Acked-by: default avatarJiri Olsa <>
Link: default avatarArnaldo Carvalho de Melo <>
parent c3537fc2
......@@ -55,7 +55,6 @@ counted. The following modifiers exist:
S - read sample value (PERF_SAMPLE_READ)
D - pin the event to the PMU
W - group is weak and will fallback to non-group if not schedulable,
only supported in 'perf stat' for now.
The 'p' modifier can be used for specifying how precise the instruction
address should be. The 'p' modifier can be specified multiple times:
......@@ -391,7 +391,12 @@ static int record__open(struct record *rec)
ui__warning("%s\n", msg);
goto try_again;
if ((errno == EINVAL || errno == EBADF) &&
pos->leader != pos &&
pos->weak_group) {
pos = perf_evlist__reset_weak_group(evlist, pos);
goto try_again;
rc = -errno;
perf_evsel__open_strerror(pos, &opts->target,
errno, msg, sizeof(msg));
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