Messages in this thread Patch in this message | | | From | David Ahern <> | Subject | [PATCH 10/11] perf tool: give user better message if precise is not supported | Date | Fri, 20 Jul 2012 17:25:55 -0600 |
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If the PEBS is not supported (e.g., a VM) and the precise modifier is set the user is given a confusing error message:
$ perf top -e cycles:p
The sys_perf_event_open() syscall returned with 95 (Operation not supported). /bin/dmesg may provide additional information. No CONFIG_PERF_EVENTS=y kernel support configured?
$ 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.
Fatal: No hardware sampling interrupt available. No APIC? If so then you can boot the kernel with the "lapic" boot parameter to force-enable it.
Which in no way conveys the real error. With this patch: $ perf top -e cycles:p PEBS request not supported. Try removing 'p' modifier
$ perf record -e cycles:p -a -- sleep 1 PEBS request not supported. Try removing 'p' modifier
Signed-off-by: David Ahern <dsahern@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> --- tools/perf/builtin-record.c | 4 ++++ tools/perf/builtin-top.c | 4 ++++ 2 files changed, 8 insertions(+)
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index f5a6452..911e300 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -267,6 +267,10 @@ try_again: ui__error("The %s event is not supported.\n", perf_evsel__name(pos)); exit(EXIT_FAILURE); + } else if ((err == ENOTSUP) && (attr->precise_ip)) { + ui__error("PEBS request not supported. " + "Try removing 'p' modifier\n"); + exit(EXIT_FAILURE); } printf("\n"); diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c index 0ce665c..1706dc9 100644 --- a/tools/perf/builtin-top.c +++ b/tools/perf/builtin-top.c @@ -968,6 +968,10 @@ 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("PEBS 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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