c++ - What's the difference between tms_utime and tms_stime with the times() function? -


what's difference between tms_utime , tms_stime exactly? i'm referring struct tms used posix times() function. data caching time included in utime? can data caching time measured separately?

ps: using linux-ubuntu. example, solving large sparse linear equation system using c++ program.

given discussing tms_utime , tms_stime members of struct tms (which contains 4 elements of type clock_t) used times(), difference outlined in first , last comments:

the tms_utime element amount of time spent executing code, or code in c library. tms_stime element amount of time spent in kernel executing code on behalf. (the tms_cutime , tms_cstime sums of tms_utime , tms_stime respectively child processes have exited — see rationale commentary.)

there no breakdown of time 'time spent waiting cache' vs 'time spent not waiting cache'. think cache time included in tms_stime value because when data isn't in cache, need system fetch you.


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