On Fri, May 04, 2012 at 12:39:18AM +0200, Jan Kara wrote:
>
> Hello,
>
> this is the second iteration of my patches for flexible proportions. Since
> previous submission, I've converted BDI proportion calculations to use flexible
> proportions so now we can test proportions in kernel. Fengguang, can you give
> them a run in your JBOD setup? You might try to tweak VM_COMPLETIONS_PERIOD_LEN
> if things are fluctuating too much... I'm not yet completely decided how to set
> that constant. Thanks!
Kara, I've got some results and it's working great. Overall performance
remains good. The default VM_COMPLETIONS_PERIOD_LEN = 0.5s is obviously
too small, so I tried increasing it to 3s and then 8s. Results for xfs
(which has most fluctuating IO completions and ditto for bdi_setpoint)
are attached. The XFS result of vanilla 3.3 is also attached. The
graphs are all for case bay/JBOD-2HDD-thresh=1000M/xfs-10dd.
Look at the gray "bdi setpoint" lines. The
VM_COMPLETIONS_PERIOD_LEN=8s kernel is able to achieve roughly the
same stable bdi_setpoint as the vanilla kernel, while being able to
adapt to the balanced bdi_setpoint much more fast (actually now the
bdi_setpoint is immediately close to the balanced value when
balance_dirty_pages() starts throttling, while the vanilla kernel
takes about 20 seconds for bdi_setpoint to grow up).
3.4.0-rc2 3.4.0-rc2-prop8+
------------------------ ------------------------
195.86 +0.0% 195.87 bay/JBOD-2HDD-thresh=1000M/btrfs-10dd-1-3.4.0-rc2
196.68 +0.1% 196.81 bay/JBOD-2HDD-thresh=1000M/btrfs-1dd-1-3.4.0-rc2
187.39 -1.1% 185.28 bay/JBOD-2HDD-thresh=1000M/ext4-10dd-1-3.4.0-rc2
191.94 +0.7% 193.27 bay/JBOD-2HDD-thresh=1000M/ext4-1dd-1-3.4.0-rc2
193.01 -0.1% 192.76 bay/JBOD-2HDD-thresh=1000M/xfs-10dd-1-3.4.0-rc2
197.28 -0.1% 197.07 bay/JBOD-2HDD-thresh=1000M/xfs-1dd-1-3.4.0-rc2
197.09 -0.2% 196.74 bay/JBOD-2HDD-thresh=100M/btrfs-1dd-1-3.4.0-rc2
160.16 -1.2% 158.21 bay/JBOD-2HDD-thresh=100M/ext4-10dd-1-3.4.0-rc2
192.10 -0.1% 191.97 bay/JBOD-2HDD-thresh=100M/ext4-1dd-1-3.4.0-rc2
163.35 +0.3% 163.79 bay/JBOD-2HDD-thresh=100M/xfs-10dd-1-3.4.0-rc2
194.90 +0.0% 194.99 bay/JBOD-2HDD-thresh=100M/xfs-1dd-1-3.4.0-rc2
191.10 +0.2% 191.53 bay/RAID0-2HDD-thresh=1000M/btrfs-1dd-1-3.4.0-rc2
183.38 +2.6% 188.12 bay/RAID0-2HDD-thresh=1000M/ext4-1dd-1-3.4.0-rc2
196.02 -0.0% 195.99 bay/RAID0-2HDD-thresh=1000M/xfs-1dd-1-3.4.0-rc2
170.18 +0.3% 170.70 bay/RAID0-2HDD-thresh=100M/btrfs-1dd-1-3.4.0-rc2
180.79 +1.6% 183.72 bay/RAID0-2HDD-thresh=100M/ext4-1dd-1-3.4.0-rc2
189.00 -0.2% 188.68 bay/RAID0-2HDD-thresh=100M/xfs-1dd-1-3.4.0-rc2
97.57 +0.0% 97.61 bay/RAID1-2HDD-thresh=1000M/btrfs-1dd-1-3.4.0-rc2
96.69 +0.8% 97.50 bay/RAID1-2HDD-thresh=1000M/ext4-1dd-1-3.4.0-rc2
96.99 +0.9% 97.86 bay/RAID1-2HDD-thresh=1000M/xfs-1dd-1-3.4.0-rc2
97.53 +0.2% 97.71 bay/RAID1-2HDD-thresh=100M/btrfs-1dd-1-3.4.0-rc2
95.85 -0.0% 95.80 bay/RAID1-2HDD-thresh=100M/ext4-1dd-1-3.4.0-rc2
97.11 +0.1% 97.23 bay/RAID1-2HDD-thresh=100M/xfs-1dd-1-3.4.0-rc2
99.38 -0.0% 99.37 bay/thresh=1000M/btrfs-1dd-1-3.4.0-rc2
98.50 +0.2% 98.65 bay/thresh=1000M/ext4-1dd-1-3.4.0-rc2
97.54 -0.0% 97.50 bay/thresh=1000M/xfs-10dd-1-3.4.0-rc2
99.67 -0.1% 99.56 bay/thresh=1000M/xfs-1dd-1-3.4.0-rc2
99.34 -0.0% 99.33 bay/thresh=100M/btrfs-1dd-1-3.4.0-rc2
97.56 -0.1% 97.44 bay/thresh=100M/ext4-1dd-1-3.4.0-rc2
87.62 +0.2% 87.83 bay/thresh=100M/xfs-10dd-1-3.4.0-rc2
99.18 +0.0% 99.21 bay/thresh=100M/xfs-1dd-1-3.4.0-rc2
86.99 -0.8% 86.33 bay/thresh=10M/btrfs-1dd-1-3.4.0-rc2
91.65 -0.2% 91.42 bay/thresh=10M/ext4-1dd-1-3.4.0-rc2
69.54 +0.2% 69.72 bay/thresh=10M/xfs-10dd-1-3.4.0-rc2
91.73 +0.4% 92.10 bay/thresh=10M/xfs-1dd-1-3.4.0-rc2
3.31 -2.7% 3.22 bay/thresh=1M/btrfs-1dd-1-3.4.0-rc2
84.17 +0.7% 84.76 bay/thresh=1M/ext4-1dd-1-3.4.0-rc2
65.87 -2.2% 64.44 bay/thresh=1M/xfs-10dd-1-3.4.0-rc2
75.02 -0.6% 74.59 bay/thresh=1M/xfs-1dd-1-3.4.0-rc2
5109.05 +0.1% 5114.70 TOTAL write_bw
3723146.77 +0.0% 3723782.19 TOTAL io_wkB_s
12136.02 -0.3% 12096.63 TOTAL io_w_s
6246.22 +0.5% 6280.40 TOTAL io_wrqm_s
7.86 -5.6% 7.42 TOTAL io_rkB_s
2.00 -5.0% 1.90 TOTAL io_r_s
0.02 -38.5% 0.01 TOTAL io_rrqm_s
35432.39 -0.0% 35417.66 TOTAL io_avgrq_sz
2804.24 +0.9% 2830.82 TOTAL io_avgqu_sz
14045.59 +1.2% 14220.95 TOTAL io_await
150.05 +28.4% 192.65 TOTAL io_svctm
14048.25 +1.3% 14223.99 TOTAL io_util
97.79 +0.4% 98.20 TOTAL cpu_user
0.00 0.00 TOTAL cpu_nice
1150.46 -0.8% 1141.17 TOTAL cpu_system
1311.93 +0.5% 1319.01 TOTAL cpu_iowait
0.00 0.00 TOTAL cpu_steal
1439.81 +0.1% 1441.63 TOTAL cpu_idle
Thanks,
Fengguang
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