Re: [RFC PATCH] cfq-iosched: IOPS mode for group scheduling and new group_idle tunable

[Vivek Goyal <vgoyal@redhat.com>]

On Fri, Jul 23, 2010 at 04:03:43PM +0200, Heinz Diehl wrote:
> On 23.07.2010, Vivek Goyal wrote: 
> 
> > This is V4 of the patchset which implements a new tunable group_idle and also
> > implements IOPS mode for group fairness. Following are changes since V3.
> [....]
> 
> Just for information: this patchset, applied to 2.6.35-rc6, gives about
> 20-25% increase in speed/throughput on my desktop system 
> (Phenom 2.5GHz Quadcore, 3 disks) with the tunables set according 
> to what you've used/reported here (the setup with slice_idle set to 0),
> and it's measurable with fs_mark, too.
> 
> After 2 hours of hard testing, the machine remains stable and responsive.

Thanks for some testing Heinz. I am assuming you are not using cgroups
and blkio controller.

In that case, you are seeing improvements probably due to first patch
where we don't idle on service tree if slice_idle=0. Hence we cut down on
overall idling and can see throughput incrase.

What kind of configuration these 3 disks are on your system? Some Hardare
RAID or software RAID ?

Thanks
Vivek