What library function can I call to get mapping of processes to cores or given a process id tell me what core it's running on, it ran last time, or scheduled to run. So something like this:
core 1: 14232,42323
core 2: 42213,63434,434
core 3: 34232,34314
core 4: 42325,6353,1434,4342
core 5: 43432,64535,14345,34233
core 6: 23242,53422,4231,34242
core 7: 78789
core 8: 23423,23124,5663
I sched_getcpu returns the core number of calling process. If there was a function that given a process id, would return the core number that would be good too but I have not found one. sched_getaffinity is not useful either; It just tells you given a process what cores it can run on which is not what I'm interested in.
Yes, the virtual file /proc/[pid]/stat seems to have this info: man 5 proc:
/proc/[pid]/stat
Status information about the process. This is used by ps(1). It is
defined in /usr/src/linux/fs/proc/array.c.
(...fields description...)
processor %d (since Linux 2.2.8)
CPU number last executed on.
on my dual core:
cat /proc/*/stat | awk '{printf "%-32s %d\n", $2 ":", $(NF-5)}'
(su): 0
(bash): 0
(tail): 1
(hd-audio0): 1
(chromium-browse): 0
(bash): 1
(upstart-socket-): 1
(rpcbind): 1
..though I can't say if it's pertinent and/or accurate..