pthreads: programmatically gather information on time spent on different states?

Question

In C, Linux 3.2: Is there a way to programmatically gather stats on the state of each pthread created thread on some program? For instance, I'd like to get the time each thread spent running, and in the idle state.

Answer 1

clock_gettime() can return the thread-specific CPU time. Simply do:

struct timespec ts;
clock_gettime(CLOCK_THREAD_CPUTIME_ID, &ts);

But from my understanding this is the sum of user and system time of this thread. Also you should consider the Warning message regarding SMP systems at the end of the man page.

Also, if you don't want timing information on the current thread, but on some pthread, you could get the clockid_t to use with clock_gettime() using int pthread_getcpuclockid(pthread_t thread, clockid_t *clock_id).

Answer 2

getrusage()

EDIT: To get idle time, I would subtract the system and user time from the total time the thread was active.

Other tools you can use to probe include: system tap, swtrace, tprof, oprofile, perf, sysprof, ptt, etc.