• Ian Rogers's avatar
    perf inject: Fix leader sampling inserting additional samples · 79bcd34e
    Ian Rogers authored
    The processing of leader samples would turn an individual sample with
    a group of read values into multiple samples. 'perf inject' would pass
    through the additional samples increasing the output data file size:
    
      $ perf record -g -e "{instructions,cycles}:S" -o perf.orig.data true
      $ perf script -D -i perf.orig.data | sed -e 's/perf.orig.data/perf.data/g' > orig.txt
      $ perf inject -i perf.orig.data -o perf.new.data
      $ perf script -D -i perf.new.data | sed -e 's/perf.new.data/perf.data/g' > new.txt
      $ diff -u orig.txt new.txt
      --- orig.txt    2024-07-29 14:29:40.606576769 -0700
      +++ new.txt     2024-07-29 14:30:04.142737434 -0700
      ...
      -0xc550@perf.data [0x30]: event: 3
      +0xc550@perf.data [0xd0]: event: 9
      +.
      +. ... raw event: size 208 bytes
      +.  0000:  09 00 00 00 01 00 d0 00 fc 72 01 86 ff ff ff ff  .........r......
      +.  0010:  74 7d 2c 00 74 7d 2c 00 fb c3 79 f9 ba d5 05 00  t},.t},...y.....
      +.  0020:  e6 cb 1a 00 00 00 00 00 01 00 00 00 00 00 00 00  ................
      +.  0030:  02 00 00 00 00 00 00 00 76 01 00 00 00 00 00 00  ........v.......
      +.  0040:  e6 cb 1a 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
      +.  0050:  62 18 00 00 00 00 00 00 f6 cb 1a 00 00 00 00 00  b...............
      +.  0060:  00 00 00 00 00 00 00 00 0c 00 00 00 00 00 00 00  ................
      +.  0070:  80 ff ff ff ff ff ff ff fc 72 01 86 ff ff ff ff  .........r......
      +.  0080:  f3 0e 6e 85 ff ff ff ff 0c cb 7f 85 ff ff ff ff  ..n.............
      +.  0090:  bc f2 87 85 ff ff ff ff 44 af 7f 85 ff ff ff ff  ........D.......
      +.  00a0:  bd be 7f 85 ff ff ff ff 26 d0 7f 85 ff ff ff ff  ........&.......
      +.  00b0:  6d a4 ff 85 ff ff ff ff ea 00 20 86 ff ff ff ff  m......... .....
      +.  00c0:  00 fe ff ff ff ff ff ff 57 14 4f 43 fc 7e 00 00  ........W.OC.~..
      +
      +1642373909693435 0xc550 [0xd0]: PERF_RECORD_SAMPLE(IP, 0x1): 2915700/2915700: 0xffffffff860172fc period: 1 addr: 0
      +... FP chain: nr:12
      +.....  0: ffffffffffffff80
      +.....  1: ffffffff860172fc
      +.....  2: ffffffff856e0ef3
      +.....  3: ffffffff857fcb0c
      +.....  4: ffffffff8587f2bc
      +.....  5: ffffffff857faf44
      +.....  6: ffffffff857fbebd
      +.....  7: ffffffff857fd026
      +.....  8: ffffffff85ffa46d
      +.....  9: ffffffff862000ea
      +..... 10: fffffffffffffe00
      +..... 11: 00007efc434f1457
      +... sample_read:
      +.... group nr 2
      +..... id 00000000001acbe6, value 0000000000000176, lost 0
      +..... id 00000000001acbf6, value 0000000000001862, lost 0
      +
      +0xc620@perf.data [0x30]: event: 3
      ...
    
    This behavior is incorrect as in the case above 'perf inject' should
    have done nothing. Fix this behavior by disabling separating samples
    for a tool that requests it. Only request this for `perf inject` so as
    to not affect other perf tools. With the patch and the test above
    there are no differences between the orig.txt and new.txt.
    
    Fixes: e4caec0d ("perf evsel: Add PERF_SAMPLE_READ sample related processing")
    Signed-off-by: default avatarIan Rogers <irogers@google.com>
    Acked-by: default avatarNamhyung Kim <namhyung@kernel.org>
    Cc: Adrian Hunter <adrian.hunter@intel.com>
    Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
    Cc: Andi Kleen <ak@linux.intel.com>
    Cc: Ingo Molnar <mingo@redhat.com>
    Cc: Jiri Olsa <jolsa@kernel.org>
    Cc: Jiri Olsa <jolsa@redhat.com>
    Cc: Kan Liang <kan.liang@linux.intel.com>
    Cc: Mark Rutland <mark.rutland@arm.com>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Link: https://lore.kernel.org/r/20240729220620.2957754-1-irogers@google.comSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
    79bcd34e
tool.h 1.97 KB