True. I was curious as to what happens when I am time sharing the CPU. -- Sent from my iPhone
On May 8, 2012, at 3:11 AM, TERRY DONTJE <terry.don...@oracle.com> wrote: > On 5/7/2012 8:40 PM, Jeff Squyres (jsquyres) wrote: >> >> On May 7, 2012, at 8:31 PM, Jingcha Joba wrote: >> >>> So in the above stated example, end-start will be: <whatever the solver >>> took> + 20ms ? >>> >>> (time slice of P2 + P3 = 20ms) >> More or less (there's nonzero amount of time required for the kernel >> scheduler, and the time quantum for each of P2 and P3 is likely not >> *exactly* 10ms). But you're over thinking this. >> >> The elapsed wall-clock time is simply (end-start). >> > To kind of add to what Jeff is saying, the case you are describing sounds > like oversubscription. If you really need to find the "pure" performance of > the code you should be running on a dedicated cluster otherwise you'll be > battling other issues in addition to timeslicing. > > -- > Terry D. Dontje | Principal Software Engineer > Developer Tools Engineering | +1.781.442.2631 > Oracle - Performance Technologies > 95 Network Drive, Burlington, MA 01803 > Email terry.don...@oracle.com > > > > _______________________________________________ > users mailing list > us...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/users
