Add a warning message to check CONFIG_EXCLUDE_KERNEL_HW_ITRACE kernel config which excludes kernel mode instruction tracing to help perf tool users identify the perf event open failure when they attempt kernel mode tracing with this config enabled.
Tested-by: Denis Nikitin denik@chromium.org Signed-off-by: Sai Prakash Ranjan saiprakash.ranjan@codeaurora.org --- tools/perf/util/evsel.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c index c26ea82220bd..09cc0349f883 100644 --- a/tools/perf/util/evsel.c +++ b/tools/perf/util/evsel.c @@ -2630,7 +2630,8 @@ int evsel__open_strerror(struct evsel *evsel, struct target *target, ">= 1: Disallow CPU event access\n" ">= 2: Disallow kernel profiling\n" "To make the adjusted perf_event_paranoid setting permanent preserve it\n" - "in /etc/sysctl.conf (e.g. kernel.perf_event_paranoid = <setting>)", + "in /etc/sysctl.conf (e.g. kernel.perf_event_paranoid = <setting>)\n\n" + "Also check CONFIG_EXCLUDE_KERNEL_HW_ITRACE if kernel mode tracing is allowed.", perf_event_paranoid()); case ENOENT: return scnprintf(msg, size, "The %s event is not supported.", evsel__name(evsel));