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| author | David Ahern <dsahern@gmail.com> | 2012-09-14 00:59:15 +0400 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2012-10-24 20:20:11 +0400 |
| commit | 2305c82fb35dd2c8c9533303bb1693f1636c66e4 (patch) | |
| tree | 5a85edf5c7b1df1d65cfef7302279002edcd77bc /Documentation/networking | |
| parent | 03f2f93ae00762eb881424df1c688d034fd341ee (diff) | |
| download | linux-2305c82fb35dd2c8c9533303bb1693f1636c66e4.tar.xz | |
perf tools: Give user better message if precise is not supported
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: David 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.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'Documentation/networking')
0 files changed, 0 insertions, 0 deletions