On Sun, Jul 31, 2016 at 7:03 AM, Adrian Chadd <adrian.ch...@gmail.com> wrote: > Hi, > > Did you test on any 1, 2, 4, 8 cpu machines? just to see if there are > any performance degredations on lower count CPUs?
The adaptive spinning path will never run on a uniprocessor. Except for potential i-cache displacement you're not going to actually see any effect unless there is substantial contention. You'll need all threads consistently contending for the same lock. A potential workload to exercise this would be to run ncpu threads sending small UDP packets on a driver with a legacy mutex protected IFQ interface. > Also, yeah, the MOD operator in each loop could get spendy on older > CPUs (eg my MIPS CPUs, older ARM stuff, etc.) Is it possible to > achieve much the same autotuning with pow2 operations instead of > divide/mod? > > > -a > _______________________________________________ > freebsd-current@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-current > To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org" _______________________________________________ freebsd-current@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org"
