On Wed, Apr 14, 2010 at 7:49 PM, Garrett Cooper <yanef...@gmail.com> wrote: > On Wed, Apr 14, 2010 at 5:46 PM, Maho NAKATA <cha...@mac.com> wrote: >> Hi Andry and Adam >> >> My test again. No desktop, etc. I just run dgemm. >> Contrary to Adam's result, Hyper Threading makes the performance worse. >> all tests are done on Core i7 920 @ 2.67GHz. (TurboBoost @2.8GHz) >> >> Turbo Boost off, Hyper threading off: 82% (35GFlops) [1] >> Turbo Boost off, Hyper threading off: 72% (30.5GFlops) [2] >> >> Turbo Boost on, Hyper threading on: 71% (32GFlops) [3] >> Turbo Boost off, Hyper threading off: 84-89% (38-40GFlops) [4] > > Doesn't this make sense? Hyperthreaded cores in Intel procs still > provide an incomplete set of registers as they're logical processors, > so I would expect for things to be slower if they're automatically run > on the SMT cores instead of the physical ones. > > Is there a weighting scheme to SCHED_ULE where logical processors > (like the SMT variety) get a lower score than real processors do, and > thus get scheduled for less intensive interrupting tasks, or maybe > just don't get scheduled in high use scenarios like it would if it was > a physical processor?
Err... wait. Didn't see that the turbo boost results didn't scale linearly or align with one another until just a sec ago. Nevermind my previous comment. -Garrett _______________________________________________ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to "freebsd-stable-unsubscr...@freebsd.org"
