Am Mittwoch 14 Mai 2008 23:14:47 schrieb James Sutherland:
Okay, then I am interpreting things correctly, and my internal timer seems to be consistent with the output of the "time" command that you refer to. To restate, the sum of "real" and "system" time is the pertinent measure. The results you posted then indicate that there is no speedup associated with increasing the number of threads. I am now seeing the same thing...
So any thoughts as to why there is no speedup?
real: the real time it took user: CPU time owned by the user it took sys: CPU time owned by the system it took Thus this timings: $time ./a.out Executing 12 tasks using 1 threads. time: 9.64 real 0m9.668s user 0m9.641s sys 0m0.004s $ time ./a.out Executing 12 tasks using 2 threads. time: 9.91 real 0m4.991s user 0m9.909s sys 0m0.012s === 0m9.668s vs. 0m4.991s say that the 2-thread version is about two times faster than the single threaded version. Best, -- Maik