• David Ahern's avatar
    perf tools: Give user better message if precise is not supported · 2305c82f
    David Ahern authored
    Platforms (e.g., VM's) without support for precise mode get a confusing
    error message. e.g.,
    $ perf record -e cycles:p -a -- sleep 1
    
      Error: sys_perf_event_open() syscall returned with 95 (Operation not
      supported).  /bin/dmesg may provide additional information.
    
      No hardware sampling interrupt available. No APIC? If so then you can
      boot the kernel with the "lapic" boot parameter to force-enable it.
      sleep: Terminated
    
    which is not clear that precise mode might be the root problem. With this
    patch:
    
    $ perf record -e cycles:p -fo /tmp/perf.data -- sleep 1
      Error:
      'precise' request may not be supported. Try removing 'p' modifier
      sleep: Terminated
    
    v2: softened message to 'may not be' supported per Robert's suggestion
    Signed-off-by: default avatarDavid Ahern <dsahern@gmail.com>
    Cc: Ingo Molnar <mingo@kernel.org>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Robert Richter <robert.richter@amd.com>
    Link: http://lkml.kernel.org/r/1347569955-54626-4-git-send-email-dsahern@gmail.comSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
    2305c82f
builtin-record.c 29.3 KB