Hello!
On Thu, Jul 28, 2011 at 11:34, Avi Kivity <avi@xxxxxxxxxx> wrote:
> Looks like you are blocked on disk. What does iostat say about disk
> utilization (in both guest and host)?
I also thought so, but host cpu states doesn't show any disk blocking.
iostat 5 with cache=none:
Guest:
avg-cpu: %user %nice %system %iowait %steal %idle
0,10 0,00 0,25 36,48 0,00 63,17
Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
vda 177,00 76,80 1308,80 384 6544
dm-0 167,00 76,80 1308,80 384 6544
dm-1 0,00 0,00 0,00 0 0
Host:
avg-cpu: %user %nice %system %iowait %steal %idle
5,62 0,00 1,47 0,50 0,00 92,40
Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
sda 185,40 0,00 1212,80 0 6064
sdb 188,60 25,60 1212,80 128 6064
md1 198,40 25,60 1212,80 128 6064
[skip]
dm-12 195,00 25,60 1177,60 128 5888
time mysql ...:
real 7m13.876s
user 0m0.338s
sys 0m0.182s
> Try s/cache=none/cache=unsafe/ as an experiment. Does it help?
With cache=unsafe:
Guest:
avg-cpu: %user %nice %system %iowait %steal %idle
3,15 0,00 8,60 11,00 0,00 77,24
Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
vda 3827,60 782,40 20587,20 3912 102936
dm-0 2638,60 779,20 20576,00 3896 102880
dm-1 0,00 0,00 0,00 0 0
Host:
avg-cpu: %user %nice %system %iowait %steal %idle
10,41 0,00 7,73 0,00 0,00 81,86
Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
sda 5,40 307,20 40,00 1536 200
sdb 5,40 460,80 40,00 2304 200
md1 99,00 768,00 27,20 3840 136
dm-12 96,00 768,00 0,00 3840 0
4 times followed by
avg-cpu: %user %nice %system %iowait %steal %idle
10,48 0,00 8,18 0,03 0,00 81,31
Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
sda 29,00 256,00 16236,80 1280 81184
sdb 27,40 0,00 16236,80 0 81184
md1 2057,80 256,00 16224,00 1280 81120
dm-12 2050,80 256,00 16150,40 1280 80752
2 times
time:
real 0m19.133s
user 0m0.429s
sys 0m0.271s
> Try s/cache=none/cache=none,aio=native/. Does it help? This one is safe,
> you can keep it if it works.
With aio=native:
Guest:
avg-cpu: %user %nice %system %iowait %steal %idle
0,20 0,00 0,50 37,08 0,00 62,22
Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
vda 192,00 78,40 1038,40 392 5192
dm-0 133,60 78,40 1040,00 392 5200
dm-1 0,00 0,00 0,00 0 0
Host:
avg-cpu: %user %nice %system %iowait %steal %idle
2,58 0,00 5,44 0,20 0,00 91,77
Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
sda 176,80 22,40 1096,00 112 5480
sdb 174,40 0,00 1096,00 0 5480
md1 181,60 22,40 1096,00 112 5480
dm-12 175,20 22,40 1038,40 112 5192
Time:
real 7m7.770s
user 0m0.352s
sys 0m0.217s
If the same mysql command is executed on host directly:
Host:
avg-cpu: %user %nice %system %iowait %steal %idle
3,96 0,00 7,54 8,90 0,00 79,60
Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
sda 1273,40 164,80 10252,80 824 51264
sdb 1304,60 352,00 10252,80 1760 51264
md1 1345,00 516,80 10252,80 2584 51264
dm-0 1343,60 516,80 10232,00 2584 51160
Time:
real 0m10.161s
user 0m0.294s
sys 0m0.284s
This is completely testing server, so I can try some new versons or patches.
--
Boris Dolgov.
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