diff mbox series

[2/4] perf evsel: Print warning for excluding kernel mode instruction tracing

Message ID 014e0ded8cb17cbf8cbdf35275bd6fb9cacdfffb.1611909025.git.saiprakash.ranjan@codeaurora.org
State Superseded
Headers show
Series Add support to exclude kernel mode hardware assisted instruction tracing | expand

Commit Message

Sai Prakash Ranjan Jan. 29, 2021, 7:05 p.m. UTC 
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(-)
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Patch

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));