The tracepoints trace_sched_stat_{wait, sleep, iowait} are not exposed to user
if CONFIG_SCHEDSTATS is not set, "perf sched record" records the three events.
As a result, the command fails.
Before:
#perf sched record sleep 1
event syntax error: 'sched:sched_stat_wait'
\___ unknown tracepoint
Error: File /sys/kernel/tracing/events/sched/sched_stat_wait not found.
Hint: Perhaps this kernel misses some CONFIG_ setting to enable this feature?.
Run 'perf list' for a list of valid events
Usage: perf record [<options>] [<command>]
or: perf record [<options>] -- <command> [<options>]
-e, --event <event> event selector. use 'perf list' to list available events
Solution:
Check whether schedstat tracepoints are exposed. If no, these events are not recorded.
After:
# perf sched record sleep 1
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.163 MB perf.data (1091 samples) ]
# perf sched report
run measurement overhead: 4736 nsecs
sleep measurement overhead: 9059979 nsecs
the run test took 999854 nsecs
the sleep test took 8945271 nsecs
nr_run_events: 716
nr_sleep_events: 785
nr_wakeup_events: 0
...
------------------------------------------------------------
Fixes: 2a09b5de23 ("sched/fair: do not expose some tracepoints to user if CONFIG_SCHEDSTATS is not set")
Signed-off-by: Yang Jihong <yangjihong1@huawei.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Yafang Shao <laoar.shao@gmail.com>
Link: http://lore.kernel.org/lkml/20210713112358.194693-1-yangjihong1@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
b0f008551f