From: Arnaldo Carvalho de Melo <[email protected]> When the kernel allows tweaking perf_event_max_stack and the event being setup has PERF_SAMPLE_CALLCHAIN in its perf_event_attr.sample_type, tell the user that tweaking /proc/sys/kernel/perf_event_max_stack may solve the problem.
Before: # echo 32000 > /proc/sys/kernel/perf_event_max_stack # perf record -g usleep 1 Error: The sys_perf_event_open() syscall returned with 12 (Cannot allocate memory) for event (cycles:ppp). /bin/dmesg may provide additional information. No CONFIG_PERF_EVENTS=y kernel support configured? # After: # echo 64000 > /proc/sys/kernel/perf_event_max_stack # perf record -g usleep 1 Error: Not enough memory to setup event with callchain. Hint: Try tweaking /proc/sys/kernel/perf_event_max_stack Hint: Current value: 64000 # Suggested-by: David Ahern <[email protected]> Cc: Adrian Hunter <[email protected]> Cc: Brendan Gregg <[email protected]> Cc: Frederic Weisbecker <[email protected]> Cc: Jiri Olsa <[email protected]> Cc: Milian Wolff <[email protected]> Cc: Namhyung Kim <[email protected]> Cc: Wang Nan <[email protected]> Link: http://lkml.kernel.org/n/[email protected] Signed-off-by: Arnaldo Carvalho de Melo <[email protected]> --- tools/perf/util/evsel.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c index 334364e25bbe..9bed7f4419d8 100644 --- a/tools/perf/util/evsel.c +++ b/tools/perf/util/evsel.c @@ -2325,6 +2325,14 @@ int perf_evsel__open_strerror(struct perf_evsel *evsel, struct target *target, "Probably the maximum number of open file descriptors has been reached.\n" "Hint: Try again after reducing the number of events.\n" "Hint: Try increasing the limit with 'ulimit -n <limit>'"); + case ENOMEM: + if ((evsel->attr.sample_type & PERF_SAMPLE_CALLCHAIN) != 0 && + access("/proc/sys/kernel/perf_event_max_stack", F_OK) == 0) + return scnprintf(msg, size, + "Not enough memory to setup event with callchain.\n" + "Hint: Try tweaking /proc/sys/kernel/perf_event_max_stack\n" + "Hint: Current value: %d", sysctl_perf_event_max_stack); + break; case ENODEV: if (target->cpu_list) return scnprintf(msg, size, "%s", -- 2.5.5
