Hi Arnaldo
In my case:
bash-4.1# sudo perf stat -e sched:sched_switch sleep 1
Performance counter stats for 'sleep 1':
0 sched:sched_switch
1.004714901 seconds time elapsed
And if i do:
bash-4.1# perf stat -e cs sleep 1
Performance counter stats for 'sleep 1':
1 cs
1.003306642 seconds time elapsed
To enable sampling on sched:sched_switch my perf_event_attr look like:
e_open->attr.disabled = 1;
e_open->attr.type = PERF_TYPE_TRACEPOINT;
e_open->attr.config = 87;
e_open->attr.size = sizeof(e_open->attr);
e_open->attr.sample_period = 1;
e_open->attr.inherit = 1;
e_open->attr.sample_type = PERF_SAMPLE_TIME |
PERF_SAMPLE_RAW |
PERF_SAMPLE_CPU |
PERF_SAMPLE_TID ;
e_open->attr.__reserved_1 = 0;
e_open->attr.read_format = 0;
Running in separate thread for each CPU:
perf_event_open(&e_open->attr,2552,0,-1,0)
perf_event_open(&e_open->attr,2552,1,-1,0)
But if do :
e_open->attr.disabled = 1;
e_open->attr.type = PERF_TYPE_SOFTWARE;
e_open->attr.config = PERF_COUNT_SW_CONTEXT_SWITCHES;
e_open->attr.size = sizeof(e_open->attr);
e_open->attr.sample_period = 1;
e_open->attr.inherit = 1;
e_open->attr.sample_type = PERF_SAMPLE_TIME |
PERF_SAMPLE_RAW |
PERF_SAMPLE_CPU |
PERF_SAMPLE_TID ;
e_open->attr.__reserved_1 = 0;
e_open->attr.read_format = 0;
It writes events to ring buffer but of course without any
args(prev_comm,prev_pid,next_comm,next_pid)
So i am not able to understand this difference. Why sched:sched_switch
doesnt give me any counter.
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