[dm-devel] Re: Do not overload dispatch queue (Was: Re: IO scheduler based IO controller V10)

[Mike Galbraith]

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

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

	-Mike