Messages in this thread Patch in this message | | | From | David Ahern <> | Subject | [PATCH 3/3] perf tool: give user better message if precise is not supported | Date | Mon, 10 Sep 2012 10:40:16 -0600 |
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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 not supported. Try removing 'p' modifier sleep: Terminated
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> --- tools/perf/builtin-record.c | 5 +++++ tools/perf/builtin-top.c | 4 ++++ 2 files changed, 9 insertions(+)
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index 7b8b891..ccf529b 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -294,6 +294,11 @@ try_again: perf_evsel__name(pos)); rc = -err; goto out; + } else if ((err == ENOTSUP) && (attr->precise_ip)) { + ui__error("\'precise\' request not supported. " + "Try removing 'p' modifier\n"); + rc = -err; + goto out; } printf("\n"); diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c index 0513aaa..0d3653b 100644 --- a/tools/perf/builtin-top.c +++ b/tools/perf/builtin-top.c @@ -975,6 +975,10 @@ try_again: ui__error("Too many events are opened.\n" "Try again after reducing the number of events\n"); goto out_err; + } else if ((err == ENOTSUP) && (attr->precise_ip)) { + ui__error("\'precise\' request not supported. " + "Try removing 'p' modifier\n"); + goto out_err; } ui__error("The sys_perf_event_open() syscall " -- 1.7.10.1
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