• Zhengjun Xing's avatar
    perf record: Support sample-read topdown metric group for hybrid platforms · 151e7d75
    Zhengjun Xing authored
    With the hardware TopDown metrics feature, the sample-read feature should
    be supported for a TopDown group, e.g., sample a non-topdown event and read
    a Topdown metric group. But the current perf record code errors are out.
    
    For a TopDown metric group,the slots event must be the leader of the group,
    but the leader slots event doesn't support sampling. To support sample-read
    the TopDown metric group, uses the 2nd event of the group as the "leader"
    for the purposes of sampling.
    
    Only the platform with the TopDown metric feature supports sample-read the
    topdown group. In commit acb65150 ("perf record: Support sample-read
    topdown metric group"), it adds arch_topdown_sample_read() to indicate
    whether the TopDown group supports sample-read, it should only work on the
    non-hybrid systems, this patch extends the support for hybrid platforms.
    
    Before:
    
      # ./perf record -e "{cpu_core/slots/,cpu_core/cycles/,cpu_core/topdown-retiring/}:S" -a sleep 1
      Error:
      The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (cpu_core/topdown-retiring/).
      /bin/dmesg | grep -i perf may provide additional information.
    
    After:
    
      # ./perf record -e "{cpu_core/slots/,cpu_core/cycles/,cpu_core/topdown-retiring/}:S" -a sleep 1
      [ perf record: Woken up 1 times to write data ]
      [ perf record: Captured and wrote 0.238 MB perf.data (369 samples) ]
    
    Fixes: acb65150 ("perf record: Support sample-read topdown metric group")
    Reviewed-by: default avatarKan Liang <kan.liang@linux.intel.com>
    Signed-off-by: default avatarZhengjun Xing <zhengjun.xing@linux.intel.com>
    Acked-by: default avatarIan Rogers <irogers@google.com>
    Cc: Adrian Hunter <adrian.hunter@intel.com>
    Cc: Alexander Shishkin <alexander.shishkin@intel.com>
    Cc: Andi Kleen <ak@linux.intel.com>
    Cc: Ingo Molnar <mingo@redhat.com>
    Cc: Jiri Olsa <jolsa@redhat.com>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Link: https://lore.kernel.org/r/20220602153603.1884710-1-zhengjun.xing@linux.intel.comSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
    151e7d75
topdown.c 1.62 KB