On Sat, Oct 03 2009, Mike Galbraith wrote: > On Sat, 2009-10-03 at 17:14 +0200, Jens Axboe wrote: > > On Sat, Oct 03 2009, Mike Galbraith wrote: > > > On Sat, 2009-10-03 at 16:28 +0200, Jens Axboe wrote: > > > > On Sat, Oct 03 2009, Mike Galbraith wrote: > > > > > On Sat, 2009-10-03 at 09:56 -0400, Vivek Goyal wrote: > > > > > > > > > > > I have kept the overload delay period as "cfq_slice_sync" same as Mike had > > > > > > done. We shall have to experiment what is a good waiting perioed. Is 100ms > > > > > > too long if we are waiting for a request from same process which recently > > > > > > finished IO and we did not enable idle on it. > > > > > > > > > > > > I guess we can tweak the delay period as we move along. > > > > > > > > > > I kept the delay period very short to minimize possible damage. Without > > > > > the idle thing, it wasn't enough, but with, worked a treat, as does your > > > > > patch. > > > > > > > > Can you test the current line up of patches in for-linus? It has the > > > > ramp up I talked about included as well. > > > > > > Well, it hasn't hit git.kernel.org yet, it's at... > > > > > > * block-for-linus 1d22351 cfq-iosched: add a knob for desktop interactiveness > > > > It's the top three patches here, kernel.org sync sometimes takes a > > while... > > > > http://git.kernel.dk/?p=linux-2.6-block.git;a=shortlog;h=refs/heads/for-linus > > Ok, already had the first two in, added the last. > > Entered uncharted territory for konsole -e exit, but lost a bit of > throughput for home-brew concurrent git test. > > perf stat 1.70 1.94 1.32 1.89 1.87 1.7 fairness=1 overload_delay=1 > 1.55 1.79 1.38 1.53 1.57 1.5 desktop=1 +last_end_sync > 1.09 0.87 1.11 0.96 1.11 1.0 block-for-linus So that's pure goodness, at least. > perf stat testo.sh Avg > 108.12 106.33 106.34 97.00 106.52 104.8 1.000 fairness=0 overload_delay=0 > 93.98 102.44 94.47 97.70 98.90 97.4 .929 fairness=0 overload_delay=1 > 90.87 95.40 95.79 93.09 94.25 93.8 .895 fairness=1 overload_delay=0 > 89.93 90.57 89.13 93.43 93.72 91.3 .871 fairness=1 overload_delay=1 > 89.81 88.82 91.56 96.57 89.38 91.2 .870 desktop=1 +last_end_sync > 92.61 94.60 92.35 93.17 94.05 93.3 .890 block-for-linus Doesn't look too bad, all things considered. Apart from "stock" cfq, it's consistent. And being consistent is a Good Thing. Performance wise, it's losing out to "stock" but looks pretty competetive otherwise. So far that looks like a winner. The dictator wanted good latency, he's getting good latency. I'll continue working on this on monday, while I'm waiting for delivery of the Trabant. -- Jens Axboe -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
