By looking at the scheduling stats in /proc/<PID>/sched, you can get an output like this:
[horro@system ~]$ cat /proc/1/sched
systemd (1, #threads: 1)
-------------------------------------------------------------------
se.exec_start : 2499611106.982616
se.vruntime : 7952.917943
se.sum_exec_runtime : 58651.279127
se.nr_migrations : 53355
nr_switches : 169561
nr_voluntary_switches : 168185
nr_involuntary_switches : 1376
se.load.weight : 1048576
se.avg.load_sum : 343837
se.avg.util_sum : 338827
se.avg.load_avg : 7
se.avg.util_avg : 7
se.avg.last_update_time : 2499611106982616
policy : 0
prio : 120
clock-delta : 180
mm->numa_scan_seq : 1
numa_pages_migrated : 296
numa_preferred_nid : 0
total_numa_faults : 34
current_node=0, numa_group_id=0
numa_faults node=0 task_private=0 task_shared=23 group_private=0 group_shared=0
numa_faults node=1 task_private=0 task_shared=0 group_private=0 group_shared=0
numa_faults node=2 task_private=0 task_shared=0 group_private=0 group_shared=0
numa_faults node=3 task_private=0 task_shared=11 group_private=0 group_shared=0
numa_faults node=4 task_private=0 task_shared=0 group_private=0 group_shared=0
numa_faults node=5 task_private=0 task_shared=0 group_private=0 group_shared=0
numa_faults node=6 task_private=0 task_shared=0 group_private=0 group_shared=0
numa_faults node=7 task_private=0 task_shared=0 group_private=0 group_shared=0
I have been trying to figure out what are the differences between migrations and switches, some responses here and here. Summarizing these responses:
nr_switches: number of context switches.nr_voluntary_switches: number of voluntary switches, i.e. the thread blocked and hence another thread is picked up.nr_involuntary_switches: the scheduler kicked the thread out as there is another hungry thread is ready to run.
Therefore, what are the migrations? Are these concepts related or not? Migrations are among cores and switches within a core?