On Sat, Oct 08, 2011 at 12:00:36PM +0800, Wu Fengguang wrote:
> Hi Jan,
>
> The test results look not good: btrfs is heavily impacted and the
> other filesystems are slightly impacted.
>
> I'll send you the detailed logs in private emails (too large for the
> mailing list). Basically I noticed many writeback_wait traces that
> never appear w/o this patch. In the btrfs cases that see larger
> regressions, I see large fluctuations in the writeout bandwidth and
> long disk idle periods. It's still a bit puzzling how all these
> happen..
Sorry I find that part of the regressions (about 2-3%) are caused by
change of my test scripts recently. Here are the more fair compares
and they show only regressions in btrfs and xfs:
3.1.0-rc8-ioless6a+ 3.1.0-rc8-ioless6-requeue+
------------------------ ------------------------
37.34 +0.8% 37.65 thresh=100M/ext3-10dd-4k-8p-4096M-100M:10-X
44.44 +3.4% 45.96 thresh=100M/ext3-1dd-4k-8p-4096M-100M:10-X
41.70 +1.0% 42.14 thresh=100M/ext3-2dd-4k-8p-4096M-100M:10-X
46.45 -0.3% 46.32 thresh=100M/ext4-10dd-4k-8p-4096M-100M:10-X
56.60 -0.3% 56.41 thresh=100M/ext4-1dd-4k-8p-4096M-100M:10-X
54.14 +0.9% 54.63 thresh=100M/ext4-2dd-4k-8p-4096M-100M:10-X
30.66 -0.7% 30.44 thresh=1G/ext3-100dd-4k-8p-4096M-1024M:10-X
35.24 +1.6% 35.82 thresh=1G/ext3-10dd-4k-8p-4096M-1024M:10-X
43.58 +0.5% 43.80 thresh=1G/ext3-1dd-4k-8p-4096M-1024M:10-X
50.42 -0.6% 50.14 thresh=1G/ext4-100dd-4k-8p-4096M-1024M:10-X
56.23 -1.0% 55.64 thresh=1G/ext4-10dd-4k-8p-4096M-1024M:10-X
58.12 -0.5% 57.84 thresh=1G/ext4-1dd-4k-8p-4096M-1024M:10-X
45.37 +1.4% 46.03 thresh=8M/ext3-1dd-4k-8p-4096M-8M:10-X
43.71 +2.2% 44.69 thresh=8M/ext3-2dd-4k-8p-4096M-8M:10-X
35.58 +0.5% 35.77 thresh=8M/ext4-10dd-4k-8p-4096M-8M:10-X
56.39 +1.4% 57.16 thresh=8M/ext4-1dd-4k-8p-4096M-8M:10-X
51.26 +1.5% 52.04 thresh=8M/ext4-2dd-4k-8p-4096M-8M:10-X
787.25 +0.7% 792.47 TOTAL
3.1.0-rc8-ioless6a+ 3.1.0-rc8-ioless6-requeue+
------------------------ ------------------------
44.53 -18.6% 36.23 thresh=100M/xfs-10dd-4k-8p-4096M-100M:10-X
55.89 -0.4% 55.64 thresh=100M/xfs-1dd-4k-8p-4096M-100M:10-X
51.11 +0.5% 51.35 thresh=100M/xfs-2dd-4k-8p-4096M-100M:10-X
41.76 -4.8% 39.77 thresh=1G/xfs-100dd-4k-8p-4096M-1024M:10-X
48.34 -0.3% 48.18 thresh=1G/xfs-10dd-4k-8p-4096M-1024M:10-X
52.36 -0.2% 52.26 thresh=1G/xfs-1dd-4k-8p-4096M-1024M:10-X
31.07 -1.1% 30.74 thresh=8M/xfs-10dd-4k-8p-4096M-8M:10-X
55.44 -0.6% 55.09 thresh=8M/xfs-1dd-4k-8p-4096M-8M:10-X
47.59 -31.2% 32.74 thresh=8M/xfs-2dd-4k-8p-4096M-8M:10-X
428.07 -6.1% 401.99 TOTAL
3.1.0-rc8-ioless6a+ 3.1.0-rc8-ioless6-requeue+
------------------------ ------------------------
58.23 -82.6% 10.13 thresh=100M/btrfs-10dd-4k-8p-4096M-100M:10-X
58.43 -80.3% 11.54 thresh=100M/btrfs-1dd-4k-8p-4096M-100M:10-X
58.53 -79.9% 11.76 thresh=100M/btrfs-2dd-4k-8p-4096M-100M:10-X
56.55 -31.7% 38.63 thresh=1G/btrfs-100dd-4k-8p-4096M-1024M:10-X
56.11 -30.1% 39.25 thresh=1G/btrfs-10dd-4k-8p-4096M-1024M:10-X
56.21 -18.3% 45.93 thresh=1G/btrfs-1dd-4k-8p-4096M-1024M:10-X
344.06 -54.3% 157.24 TOTAL
I'm now bisecting the patches to find out the root cause.
Thanks,
Fengguang
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