Messages in this thread | | | Date | Mon, 6 May 2002 18:42:53 +0200 | From | Andrea Arcangeli <> | Subject | Re: O(1) scheduler gives big boost to tbench 192 |
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On Mon, May 06, 2002 at 04:20:05AM -0400, rwhron@earthlink.net wrote: > > BTW, Randy, I seen my tree runs slower with tiobench, that's probably > > because I made the elevator anti-starvation logic more aggressive than > > mainline and the other kernel trees (to help interactive usage), could > > you try to run tiobench on -aa after elvtune -r 8192 -w 16384 > > /dev/hd[abcd] to verify? Thanks for the great benchmarking effort. > > I will have results on the big machine in a couple days. On the > small machine, elvtune increases tiobench sequential reads by > 30-50%, and lowers worst case latency a little.
ok, everything is fine then, thanks for the further benchmarks. Not sure if I should increase the elvtune defaults, the max latency with 8 reading threads literally doubles (from a mean of 500/600 to 1200). OTOH with 128 threads max latency even decreases (most probably because of higher mean throughput).
> > And for the reason fork is faster in -aa that's partly thanks to the > > reschedule-child-first logic, that can be easily merged in mainline, > > it's just in 2.5. > > Is that part of parent_timeslice patch? parent_timeslice helped
Yep.
> fork a little when I tried to isolating patches to find what > makes fork faster in -aa. It is more than one patch as far as > I can tell. > > On uniprocessor the unixbench execl test, all -aa kernel's going back > at least to 2.4.15aa1 are about 20% faster than other trees, even those > like jam and akpm's splitted vm. Fork in -aa for more "real world" > test (autoconf build) is about 8-10% over other kernel trees. > > On quad Xeon, with bigger L2 cache, autoconf (fork test) the difference > between mainline and -aa is smaller. The -aa based VMs in aa, jam, and > mainline have about 15% edge over rmap VM in ac and rmap. jam has a > slight advantage for autoconf build, possibly because of O(1) effect > which is more likely to show up since more processes execute > on the 4 way box. > > More quad Xeon at: > http://home.earthlink.net/~rwhron/kernel/bigbox.html > > > -- > Randy Hron
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