[PATCH 1/4] perf tools: Add verbose output for sys_perf_event_open fallback

From: Jiri Olsa
Date: Fri Jul 21 2017 - 08:12:26 EST


Adding info about what is being switched off in
the sys_perf_event_open fallback.

New output (notice the 'switching off' lines):
$ perf stat -e '{cycles,instructions}' -vvv ls
Using CPUID GenuineIntel-6-3D
intel_pt default config: tsc
------------------------------------------------------------
perf_event_attr:
size 112
sample_type IDENTIFIER
read_format TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING|ID|GROUP
disabled 1
inherit 1
enable_on_exec 1
exclude_guest 1
------------------------------------------------------------
sys_perf_event_open: pid 3591 cpu -1 group_fd -1 flags 0x8
sys_perf_event_open failed, error -22
switching off cloexec flag
------------------------------------------------------------
perf_event_attr:
size 112
sample_type IDENTIFIER
read_format TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING|ID|GROUP
disabled 1
inherit 1
enable_on_exec 1
exclude_guest 1
------------------------------------------------------------
sys_perf_event_open: pid 3591 cpu -1 group_fd -1 flags 0
sys_perf_event_open failed, error -22
switching off exclude_guest, exclude_host
------------------------------------------------------------
perf_event_attr:
size 112
sample_type IDENTIFIER
read_format TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING|ID|GROUP
disabled 1
inherit 1
enable_on_exec 1
------------------------------------------------------------
sys_perf_event_open: pid 3591 cpu -1 group_fd -1 flags 0
sys_perf_event_open failed, error -22
switching off sample_id_all
------------------------------------------------------------
perf_event_attr:
size 112
sample_type IDENTIFIER
read_format TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING|ID|GROUP
disabled 1
inherit 1
enable_on_exec 1
...

Link: http://lkml.kernel.org/n/tip-jbzet07v499dnc1umzj2ron2@xxxxxxxxxxxxxx
Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
---
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 6dd069a41ac3..450b5fadf8cb 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -1671,31 +1671,39 @@ int perf_evsel__open(struct perf_evsel *evsel, struct cpu_map *cpus,
*/
if (!perf_missing_features.write_backward && evsel->attr.write_backward) {
perf_missing_features.write_backward = true;
+ pr_debug2("switching off write_backward\n");
goto out_close;
} else if (!perf_missing_features.clockid_wrong && evsel->attr.use_clockid) {
perf_missing_features.clockid_wrong = true;
+ pr_debug2("switching off clockid\n");
goto fallback_missing_features;
} else if (!perf_missing_features.clockid && evsel->attr.use_clockid) {
perf_missing_features.clockid = true;
+ pr_debug2("switching off use_clockid\n");
goto fallback_missing_features;
} else if (!perf_missing_features.cloexec && (flags & PERF_FLAG_FD_CLOEXEC)) {
perf_missing_features.cloexec = true;
+ pr_debug2("switching off cloexec flag\n");
goto fallback_missing_features;
} else if (!perf_missing_features.mmap2 && evsel->attr.mmap2) {
perf_missing_features.mmap2 = true;
+ pr_debug2("switching off mmap2\n");
goto fallback_missing_features;
} else if (!perf_missing_features.exclude_guest &&
(evsel->attr.exclude_guest || evsel->attr.exclude_host)) {
perf_missing_features.exclude_guest = true;
+ pr_debug2("switching off exclude_guest, exclude_host\n");
goto fallback_missing_features;
} else if (!perf_missing_features.sample_id_all) {
perf_missing_features.sample_id_all = true;
+ pr_debug2("switching off sample_id_all\n");
goto retry_sample_id;
} else if (!perf_missing_features.lbr_flags &&
(evsel->attr.branch_sample_type &
(PERF_SAMPLE_BRANCH_NO_CYCLES |
PERF_SAMPLE_BRANCH_NO_FLAGS))) {
perf_missing_features.lbr_flags = true;
+ pr_debug2("switching off branch sample type no (cycles/flags)\n");
goto fallback_missing_features;
}
out_close:
--
2.9.4