Messages in this thread | | | Date | Fri, 23 Jul 2010 16:56:31 +0200 | From | Heinz Diehl <> | Subject | Re: [RFC PATCH] cfq-iosched: IOPS mode for group scheduling and new group_idle tunable |
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On 23.07.2010, Vivek Goyal wrote:
> Thanks for some testing Heinz. I am assuming you are not using cgroups > and blkio controller.
Not at all.
> 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.
Hmm, in any case it's not getting worse by setting slice_idle to 8.
My main motivation to test your patches was that I thought the other way 'round, and was just curious on how this patchset will affect machines which are NOT a high end server/storage system :-)
> What kind of configuration these 3 disks are on your system? Some Hardare > RAID or software RAID ?
Just 3 SATA disks plugged into the onboard controller, no RAID or whatsoever.
I used fs_mark for testing: "fs_mark -S 1 -D 10000 -N 100000 -d /home/htd/fsmark/test -s 65536 -t 1 -w 4096 -F"
These are the results with plain cfq (2.6.35-rc6) and the settings which gave the best speed/throughput on my machine:
low_latency = 0 slice_idle = 4 quantum = 32
Setting slice_idle to 0 didn't improve anything, I tried this before.
FSUse% Count Size Files/sec App Overhead 27 1000 65536 360.3 34133 27 2000 65536 384.4 34657 27 3000 65536 401.1 32994 27 4000 65536 394.3 33781 27 5000 65536 406.8 32569 27 6000 65536 401.9 34001 27 7000 65536 374.5 33192 27 8000 65536 398.3 32839 27 9000 65536 405.2 34110 27 10000 65536 398.9 33887 27 11000 65536 402.3 34111 27 12000 65536 398.1 33652 27 13000 65536 412.9 32443 27 14000 65536 408.1 32197
And this is after applying your patchset, with your settings (and slice_idle = 0):
FSUse% Count Size Files/sec App Overhead 27 1000 65536 600.7 29579 27 2000 65536 568.4 30650 27 3000 65536 522.0 29171 27 4000 65536 534.1 29751 27 5000 65536 550.7 30168 27 6000 65536 521.7 30158 27 7000 65536 493.3 29211 27 8000 65536 495.3 30183 27 9000 65536 587.8 29881 27 10000 65536 469.9 29602 27 11000 65536 482.7 29557 27 12000 65536 486.6 30700 27 13000 65536 516.1 30243
There's some 2-3% further improvement on my system with these settings, which after som fiddling turned out to give most performance here (don't need the group settings, of course):
group_idle = 0 group_isolation = 0 low_latency = 1 quantum = 8 slice_idle = 8
Thanks, Heinz.
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