* [Qemu-devel] virtio-blk and virtio-scsi performance comparison
@ 2015-04-15 8:17 Konstantin Krotov
2015-04-16 1:27 ` Fam Zheng
0 siblings, 1 reply; 7+ messages in thread
From: Konstantin Krotov @ 2015-04-15 8:17 UTC (permalink / raw)
To: qemu-devel
Hello list!
I performed tests with fio and obtained results:
*** virtio-scsi with cache=none, io=threads, blok device is md-device
from mdadm raid1, random r/w, 32 thread from guest (debian, kernel 3.16):
fio fio1
readtest: (g=0): rw=randrw, bs=4K-4K/4K-4K/4K-4K, ioengine=libaio,
iodepth=32
fio-2.1.11
Starting 1 process
Jobs: 1 (f=1): [m(1)] [100.0% done] [126.2MB/125.1MB/0KB /s]
[32.3K/32.3K/0 iops] [eta 00m:00s]
readtest: (groupid=0, jobs=1): err= 0: pid=707: Wed Apr 8 07:35:01 2015
read : io=5117.4MB, bw=125830KB/s, iops=31457, runt= 41645msec
slat (usec): min=4, max=343, avg=11.45, stdev=10.24
clat (usec): min=104, max=16667, avg=484.09, stdev=121.96
lat (usec): min=112, max=16672, avg=495.90, stdev=123.67
clat percentiles (usec):
| 1.00th=[ 302], 5.00th=[ 346], 10.00th=[ 374], 20.00th=[ 406],
| 30.00th=[ 426], 40.00th=[ 446], 50.00th=[ 462], 60.00th=[ 482],
| 70.00th=[ 506], 80.00th=[ 540], 90.00th=[ 596], 95.00th=[ 732],
| 99.00th=[ 948], 99.50th=[ 996], 99.90th=[ 1176], 99.95th=[ 1240],
| 99.99th=[ 1384]
bw (KB /s): min=67392, max=135216, per=99.99%, avg=125813.01,
stdev=12524.05
write: io=5114.7MB, bw=125763KB/s, iops=31440, runt= 41645msec
slat (usec): min=4, max=388, avg=11.85, stdev=10.47
clat (usec): min=147, max=8968, avg=505.23, stdev=127.40
lat (usec): min=155, max=8973, avg=517.45, stdev=128.97
clat percentiles (usec):
| 1.00th=[ 334], 5.00th=[ 370], 10.00th=[ 394], 20.00th=[ 426],
| 30.00th=[ 446], 40.00th=[ 462], 50.00th=[ 478], 60.00th=[ 498],
| 70.00th=[ 524], 80.00th=[ 556], 90.00th=[ 628], 95.00th=[ 756],
| 99.00th=[ 988], 99.50th=[ 1064], 99.90th=[ 1288], 99.95th=[ 1368],
| 99.99th=[ 2224]
bw (KB /s): min=67904, max=136384, per=99.99%, avg=125746.89,
stdev=12449.56
lat (usec) : 250=0.05%, 500=64.27%, 750=30.80%, 1000=4.20%
lat (msec) : 2=0.67%, 4=0.01%, 10=0.01%, 20=0.01%
cpu : usr=18.03%, sys=76.42%, ctx=26617, majf=0, minf=7
IO depths : 1=0.1%, 2=0.1%, 4=0.1%, 8=0.1%, 16=0.1%, 32=100.0%,
>=64=0.0%
submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%,
>=64=0.0%
complete : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.1%, 64=0.0%,
>=64=0.0%
issued : total=r=1310044/w=1309348/d=0, short=r=0/w=0/d=0
latency : target=0, window=0, percentile=100.00%, depth=32
Run status group 0 (all jobs):
READ: io=5117.4MB, aggrb=125829KB/s, minb=125829KB/s,
maxb=125829KB/s, mint=41645msec, maxt=41645msec
WRITE: io=5114.7MB, aggrb=125762KB/s, minb=125762KB/s,
maxb=125762KB/s, mint=41645msec, maxt=41645msec
Disk stats (read/write):
sda: ios=1302885/1302192, merge=55/0, ticks=281040/321660,
in_queue=601264, util=99.29%
same guest,
*** virtio-blk with cache=none, io=threads, blok device is md-device
from mdadm raid1, random r/w, 32 thread from guest (debian, kernel 3.16):
fio fio1
readtest: (g=0): rw=randrw, bs=4K-4K/4K-4K/4K-4K, ioengine=libaio,
iodepth=32
fio-2.1.11
Starting 1 process
Jobs: 1 (f=1): [m(1)] [100.0% done] [123.7MB/123.3MB/0KB /s]
[31.7K/31.6K/0 iops] [eta 00m:00s]
readtest: (groupid=0, jobs=1): err= 0: pid=810: Wed Apr 8 07:26:37 2015
read : io=5117.4MB, bw=148208KB/s, iops=37051, runt= 35357msec
slat (usec): min=2, max=2513, avg= 7.27, stdev=10.28
clat (usec): min=104, max=10716, avg=382.30, stdev=113.38
lat (usec): min=108, max=10719, avg=389.94, stdev=115.48
clat percentiles (usec):
| 1.00th=[ 215], 5.00th=[ 249], 10.00th=[ 270], 20.00th=[ 298],
| 30.00th=[ 318], 40.00th=[ 338], 50.00th=[ 358], 60.00th=[ 386],
| 70.00th=[ 418], 80.00th=[ 462], 90.00th=[ 516], 95.00th=[ 572],
| 99.00th=[ 756], 99.50th=[ 820], 99.90th=[ 996], 99.95th=[ 1176],
| 99.99th=[ 2256]
bw (KB /s): min=119296, max=165456, per=99.94%, avg=148124.33,
stdev=11834.17
write: io=5114.7MB, bw=148129KB/s, iops=37032, runt= 35357msec
slat (usec): min=2, max=2851, avg= 7.55, stdev=10.53
clat (usec): min=172, max=11080, avg=461.92, stdev=137.02
lat (usec): min=178, max=11086, avg=469.86, stdev=138.05
clat percentiles (usec):
| 1.00th=[ 278], 5.00th=[ 318], 10.00th=[ 338], 20.00th=[ 366],
| 30.00th=[ 390], 40.00th=[ 414], 50.00th=[ 438], 60.00th=[ 466],
| 70.00th=[ 494], 80.00th=[ 532], 90.00th=[ 604], 95.00th=[ 716],
| 99.00th=[ 900], 99.50th=[ 980], 99.90th=[ 1336], 99.95th=[ 1704],
| 99.99th=[ 3408]
bw (KB /s): min=119656, max=166680, per=99.93%, avg=148029.21,
stdev=11824.30
lat (usec) : 250=2.71%, 500=77.22%, 750=17.60%, 1000=2.21%
lat (msec) : 2=0.24%, 4=0.02%, 10=0.01%, 20=0.01%
cpu : usr=27.92%, sys=55.44%, ctx=91283, majf=0, minf=7
IO depths : 1=0.1%, 2=0.1%, 4=0.1%, 8=0.1%, 16=0.1%, 32=100.0%,
>=64=0.0%
submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%,
>=64=0.0%
complete : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.1%, 64=0.0%,
>=64=0.0%
issued : total=r=1310044/w=1309348/d=0, short=r=0/w=0/d=0
latency : target=0, window=0, percentile=100.00%, depth=32
Run status group 0 (all jobs):
READ: io=5117.4MB, aggrb=148207KB/s, minb=148207KB/s,
maxb=148207KB/s, mint=35357msec, maxt=35357msec
WRITE: io=5114.7MB, aggrb=148128KB/s, minb=148128KB/s,
maxb=148128KB/s, mint=35357msec, maxt=35357msec
Disk stats (read/write):
vdb: ios=1302512/1301780, merge=0/0, ticks=294828/407184,
in_queue=701380, util=99.51%
In my tests virtio-scsi shows worse results than virtio-blk.
Host kernel 3.19-3, qemu-system-x86_64 -version
QEMU emulator version 2.0.0.
--
WBR
Konstantin V. Krotov
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [Qemu-devel] virtio-blk and virtio-scsi performance comparison 2015-04-15 8:17 [Qemu-devel] virtio-blk and virtio-scsi performance comparison Konstantin Krotov @ 2015-04-16 1:27 ` Fam Zheng 2015-04-16 8:04 ` Paolo Bonzini 2015-04-16 11:17 ` Konstantin Krotov 0 siblings, 2 replies; 7+ messages in thread From: Fam Zheng @ 2015-04-16 1:27 UTC (permalink / raw) To: Konstantin Krotov; +Cc: qemu-devel On Wed, 04/15 11:17, Konstantin Krotov wrote: > Hello list! > > I performed tests with fio and obtained results: > > *** virtio-scsi with cache=none, io=threads, blok device is md-device from > mdadm raid1, random r/w, 32 thread from guest (debian, kernel 3.16): > > fio fio1 > readtest: (g=0): rw=randrw, bs=4K-4K/4K-4K/4K-4K, ioengine=libaio, > iodepth=32 > fio-2.1.11 > Starting 1 process > Jobs: 1 (f=1): [m(1)] [100.0% done] [126.2MB/125.1MB/0KB /s] [32.3K/32.3K/0 > iops] [eta 00m:00s] > readtest: (groupid=0, jobs=1): err= 0: pid=707: Wed Apr 8 07:35:01 2015 > read : io=5117.4MB, bw=125830KB/s, iops=31457, runt= 41645msec > slat (usec): min=4, max=343, avg=11.45, stdev=10.24 > clat (usec): min=104, max=16667, avg=484.09, stdev=121.96 > lat (usec): min=112, max=16672, avg=495.90, stdev=123.67 > clat percentiles (usec): > | 1.00th=[ 302], 5.00th=[ 346], 10.00th=[ 374], 20.00th=[ 406], > | 30.00th=[ 426], 40.00th=[ 446], 50.00th=[ 462], 60.00th=[ 482], > | 70.00th=[ 506], 80.00th=[ 540], 90.00th=[ 596], 95.00th=[ 732], > | 99.00th=[ 948], 99.50th=[ 996], 99.90th=[ 1176], 99.95th=[ 1240], > | 99.99th=[ 1384] > bw (KB /s): min=67392, max=135216, per=99.99%, avg=125813.01, > stdev=12524.05 > write: io=5114.7MB, bw=125763KB/s, iops=31440, runt= 41645msec > slat (usec): min=4, max=388, avg=11.85, stdev=10.47 > clat (usec): min=147, max=8968, avg=505.23, stdev=127.40 > lat (usec): min=155, max=8973, avg=517.45, stdev=128.97 > clat percentiles (usec): > | 1.00th=[ 334], 5.00th=[ 370], 10.00th=[ 394], 20.00th=[ 426], > | 30.00th=[ 446], 40.00th=[ 462], 50.00th=[ 478], 60.00th=[ 498], > | 70.00th=[ 524], 80.00th=[ 556], 90.00th=[ 628], 95.00th=[ 756], > | 99.00th=[ 988], 99.50th=[ 1064], 99.90th=[ 1288], 99.95th=[ 1368], > | 99.99th=[ 2224] > bw (KB /s): min=67904, max=136384, per=99.99%, avg=125746.89, > stdev=12449.56 > lat (usec) : 250=0.05%, 500=64.27%, 750=30.80%, 1000=4.20% > lat (msec) : 2=0.67%, 4=0.01%, 10=0.01%, 20=0.01% > cpu : usr=18.03%, sys=76.42%, ctx=26617, majf=0, minf=7 > IO depths : 1=0.1%, 2=0.1%, 4=0.1%, 8=0.1%, 16=0.1%, 32=100.0%, > >=64=0.0% > submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, > >=64=0.0% > complete : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.1%, 64=0.0%, > >=64=0.0% > issued : total=r=1310044/w=1309348/d=0, short=r=0/w=0/d=0 > latency : target=0, window=0, percentile=100.00%, depth=32 > > Run status group 0 (all jobs): > READ: io=5117.4MB, aggrb=125829KB/s, minb=125829KB/s, maxb=125829KB/s, > mint=41645msec, maxt=41645msec > WRITE: io=5114.7MB, aggrb=125762KB/s, minb=125762KB/s, maxb=125762KB/s, > mint=41645msec, maxt=41645msec > > Disk stats (read/write): > sda: ios=1302885/1302192, merge=55/0, ticks=281040/321660, > in_queue=601264, util=99.29% > > > same guest, > *** virtio-blk with cache=none, io=threads, blok device is md-device from > mdadm raid1, random r/w, 32 thread from guest (debian, kernel 3.16): > > fio fio1 > readtest: (g=0): rw=randrw, bs=4K-4K/4K-4K/4K-4K, ioengine=libaio, > iodepth=32 > fio-2.1.11 > Starting 1 process > Jobs: 1 (f=1): [m(1)] [100.0% done] [123.7MB/123.3MB/0KB /s] [31.7K/31.6K/0 > iops] [eta 00m:00s] > readtest: (groupid=0, jobs=1): err= 0: pid=810: Wed Apr 8 07:26:37 2015 > read : io=5117.4MB, bw=148208KB/s, iops=37051, runt= 35357msec > slat (usec): min=2, max=2513, avg= 7.27, stdev=10.28 > clat (usec): min=104, max=10716, avg=382.30, stdev=113.38 > lat (usec): min=108, max=10719, avg=389.94, stdev=115.48 > clat percentiles (usec): > | 1.00th=[ 215], 5.00th=[ 249], 10.00th=[ 270], 20.00th=[ 298], > | 30.00th=[ 318], 40.00th=[ 338], 50.00th=[ 358], 60.00th=[ 386], > | 70.00th=[ 418], 80.00th=[ 462], 90.00th=[ 516], 95.00th=[ 572], > | 99.00th=[ 756], 99.50th=[ 820], 99.90th=[ 996], 99.95th=[ 1176], > | 99.99th=[ 2256] > bw (KB /s): min=119296, max=165456, per=99.94%, avg=148124.33, > stdev=11834.17 > write: io=5114.7MB, bw=148129KB/s, iops=37032, runt= 35357msec > slat (usec): min=2, max=2851, avg= 7.55, stdev=10.53 > clat (usec): min=172, max=11080, avg=461.92, stdev=137.02 > lat (usec): min=178, max=11086, avg=469.86, stdev=138.05 > clat percentiles (usec): > | 1.00th=[ 278], 5.00th=[ 318], 10.00th=[ 338], 20.00th=[ 366], > | 30.00th=[ 390], 40.00th=[ 414], 50.00th=[ 438], 60.00th=[ 466], > | 70.00th=[ 494], 80.00th=[ 532], 90.00th=[ 604], 95.00th=[ 716], > | 99.00th=[ 900], 99.50th=[ 980], 99.90th=[ 1336], 99.95th=[ 1704], > | 99.99th=[ 3408] > bw (KB /s): min=119656, max=166680, per=99.93%, avg=148029.21, > stdev=11824.30 > lat (usec) : 250=2.71%, 500=77.22%, 750=17.60%, 1000=2.21% > lat (msec) : 2=0.24%, 4=0.02%, 10=0.01%, 20=0.01% > cpu : usr=27.92%, sys=55.44%, ctx=91283, majf=0, minf=7 > IO depths : 1=0.1%, 2=0.1%, 4=0.1%, 8=0.1%, 16=0.1%, 32=100.0%, > >=64=0.0% > submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, > >=64=0.0% > complete : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.1%, 64=0.0%, > >=64=0.0% > issued : total=r=1310044/w=1309348/d=0, short=r=0/w=0/d=0 > latency : target=0, window=0, percentile=100.00%, depth=32 > > Run status group 0 (all jobs): > READ: io=5117.4MB, aggrb=148207KB/s, minb=148207KB/s, maxb=148207KB/s, > mint=35357msec, maxt=35357msec > WRITE: io=5114.7MB, aggrb=148128KB/s, minb=148128KB/s, maxb=148128KB/s, > mint=35357msec, maxt=35357msec > > Disk stats (read/write): > vdb: ios=1302512/1301780, merge=0/0, ticks=294828/407184, in_queue=701380, > util=99.51% > > In my tests virtio-scsi shows worse results than virtio-blk. > Host kernel 3.19-3, qemu-system-x86_64 -version > QEMU emulator version 2.0.0. Hi Konstantin, Thanks for sharing your test result with us! It is not surprising that virtio-blk performs better in such a test. It has a much smaller command set, which results in both a simpler device model and probably a simpler guest driver. virtio-scsi, on the other hand, provides more features and means to be more scalable (you won't need to painfully mess with pci bridges to attach 1000 disks). Anyway, we are working on improving virtio-scsi performance, although it's theoretically impossible to make it faster or even equally fast. Regarding your test, I think with current code base, it generally performs better if you use io=native. Have you compared that? Fam ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [Qemu-devel] virtio-blk and virtio-scsi performance comparison 2015-04-16 1:27 ` Fam Zheng @ 2015-04-16 8:04 ` Paolo Bonzini 2015-04-16 11:17 ` Konstantin Krotov 1 sibling, 0 replies; 7+ messages in thread From: Paolo Bonzini @ 2015-04-16 8:04 UTC (permalink / raw) To: Fam Zheng, Konstantin Krotov; +Cc: qemu-devel On 16/04/2015 03:27, Fam Zheng wrote: > > virtio-scsi, on the other hand, provides more features and means to be more > scalable (you won't need to painfully mess with pci bridges to attach 1000 > disks). > > Anyway, we are working on improving virtio-scsi performance, although it's > theoretically impossible to make it faster or even equally fast. > > Regarding your test, I think with current code base, it generally performs > better if you use io=native. Have you compared that? Also, make sure you're using the deadline scheduler in both host and guest. Paolo ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [Qemu-devel] virtio-blk and virtio-scsi performance comparison 2015-04-16 1:27 ` Fam Zheng 2015-04-16 8:04 ` Paolo Bonzini @ 2015-04-16 11:17 ` Konstantin Krotov 2015-04-16 11:57 ` Paolo Bonzini 1 sibling, 1 reply; 7+ messages in thread From: Konstantin Krotov @ 2015-04-16 11:17 UTC (permalink / raw) To: Fam Zheng; +Cc: qemu-devel 16.04.2015 04:27, Fam Zheng пишет: > On Wed, 04/15 11:17, Konstantin Krotov wrote: >> Hello list! >> >> I performed tests with fio and obtained results: >> >> *** virtio-scsi with cache=none, io=threads, blok device is md-device from >> mdadm raid1, random r/w, 32 thread from guest (debian, kernel 3.16): >> >> fio fio1 >> readtest: (g=0): rw=randrw, bs=4K-4K/4K-4K/4K-4K, ioengine=libaio, >> iodepth=32 >> fio-2.1.11 >> Starting 1 process >> Jobs: 1 (f=1): [m(1)] [100.0% done] [126.2MB/125.1MB/0KB /s] [32.3K/32.3K/0 >> iops] [eta 00m:00s] >> readtest: (groupid=0, jobs=1): err= 0: pid=707: Wed Apr 8 07:35:01 2015 >> read : io=5117.4MB, bw=125830KB/s, iops=31457, runt= 41645msec >> slat (usec): min=4, max=343, avg=11.45, stdev=10.24 >> clat (usec): min=104, max=16667, avg=484.09, stdev=121.96 >> lat (usec): min=112, max=16672, avg=495.90, stdev=123.67 >> clat percentiles (usec): >> | 1.00th=[ 302], 5.00th=[ 346], 10.00th=[ 374], 20.00th=[ 406], >> | 30.00th=[ 426], 40.00th=[ 446], 50.00th=[ 462], 60.00th=[ 482], >> | 70.00th=[ 506], 80.00th=[ 540], 90.00th=[ 596], 95.00th=[ 732], >> | 99.00th=[ 948], 99.50th=[ 996], 99.90th=[ 1176], 99.95th=[ 1240], >> | 99.99th=[ 1384] >> bw (KB /s): min=67392, max=135216, per=99.99%, avg=125813.01, >> stdev=12524.05 >> write: io=5114.7MB, bw=125763KB/s, iops=31440, runt= 41645msec >> slat (usec): min=4, max=388, avg=11.85, stdev=10.47 >> clat (usec): min=147, max=8968, avg=505.23, stdev=127.40 >> lat (usec): min=155, max=8973, avg=517.45, stdev=128.97 >> clat percentiles (usec): >> | 1.00th=[ 334], 5.00th=[ 370], 10.00th=[ 394], 20.00th=[ 426], >> | 30.00th=[ 446], 40.00th=[ 462], 50.00th=[ 478], 60.00th=[ 498], >> | 70.00th=[ 524], 80.00th=[ 556], 90.00th=[ 628], 95.00th=[ 756], >> | 99.00th=[ 988], 99.50th=[ 1064], 99.90th=[ 1288], 99.95th=[ 1368], >> | 99.99th=[ 2224] >> bw (KB /s): min=67904, max=136384, per=99.99%, avg=125746.89, >> stdev=12449.56 >> lat (usec) : 250=0.05%, 500=64.27%, 750=30.80%, 1000=4.20% >> lat (msec) : 2=0.67%, 4=0.01%, 10=0.01%, 20=0.01% >> cpu : usr=18.03%, sys=76.42%, ctx=26617, majf=0, minf=7 >> IO depths : 1=0.1%, 2=0.1%, 4=0.1%, 8=0.1%, 16=0.1%, 32=100.0%, >>> =64=0.0% >> submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >>> =64=0.0% >> complete : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.1%, 64=0.0%, >>> =64=0.0% >> issued : total=r=1310044/w=1309348/d=0, short=r=0/w=0/d=0 >> latency : target=0, window=0, percentile=100.00%, depth=32 >> >> Run status group 0 (all jobs): >> READ: io=5117.4MB, aggrb=125829KB/s, minb=125829KB/s, maxb=125829KB/s, >> mint=41645msec, maxt=41645msec >> WRITE: io=5114.7MB, aggrb=125762KB/s, minb=125762KB/s, maxb=125762KB/s, >> mint=41645msec, maxt=41645msec >> >> Disk stats (read/write): >> sda: ios=1302885/1302192, merge=55/0, ticks=281040/321660, >> in_queue=601264, util=99.29% >> >> >> same guest, >> *** virtio-blk with cache=none, io=threads, blok device is md-device from >> mdadm raid1, random r/w, 32 thread from guest (debian, kernel 3.16): >> >> fio fio1 >> readtest: (g=0): rw=randrw, bs=4K-4K/4K-4K/4K-4K, ioengine=libaio, >> iodepth=32 >> fio-2.1.11 >> Starting 1 process >> Jobs: 1 (f=1): [m(1)] [100.0% done] [123.7MB/123.3MB/0KB /s] [31.7K/31.6K/0 >> iops] [eta 00m:00s] >> readtest: (groupid=0, jobs=1): err= 0: pid=810: Wed Apr 8 07:26:37 2015 >> read : io=5117.4MB, bw=148208KB/s, iops=37051, runt= 35357msec >> slat (usec): min=2, max=2513, avg= 7.27, stdev=10.28 >> clat (usec): min=104, max=10716, avg=382.30, stdev=113.38 >> lat (usec): min=108, max=10719, avg=389.94, stdev=115.48 >> clat percentiles (usec): >> | 1.00th=[ 215], 5.00th=[ 249], 10.00th=[ 270], 20.00th=[ 298], >> | 30.00th=[ 318], 40.00th=[ 338], 50.00th=[ 358], 60.00th=[ 386], >> | 70.00th=[ 418], 80.00th=[ 462], 90.00th=[ 516], 95.00th=[ 572], >> | 99.00th=[ 756], 99.50th=[ 820], 99.90th=[ 996], 99.95th=[ 1176], >> | 99.99th=[ 2256] >> bw (KB /s): min=119296, max=165456, per=99.94%, avg=148124.33, >> stdev=11834.17 >> write: io=5114.7MB, bw=148129KB/s, iops=37032, runt= 35357msec >> slat (usec): min=2, max=2851, avg= 7.55, stdev=10.53 >> clat (usec): min=172, max=11080, avg=461.92, stdev=137.02 >> lat (usec): min=178, max=11086, avg=469.86, stdev=138.05 >> clat percentiles (usec): >> | 1.00th=[ 278], 5.00th=[ 318], 10.00th=[ 338], 20.00th=[ 366], >> | 30.00th=[ 390], 40.00th=[ 414], 50.00th=[ 438], 60.00th=[ 466], >> | 70.00th=[ 494], 80.00th=[ 532], 90.00th=[ 604], 95.00th=[ 716], >> | 99.00th=[ 900], 99.50th=[ 980], 99.90th=[ 1336], 99.95th=[ 1704], >> | 99.99th=[ 3408] >> bw (KB /s): min=119656, max=166680, per=99.93%, avg=148029.21, >> stdev=11824.30 >> lat (usec) : 250=2.71%, 500=77.22%, 750=17.60%, 1000=2.21% >> lat (msec) : 2=0.24%, 4=0.02%, 10=0.01%, 20=0.01% >> cpu : usr=27.92%, sys=55.44%, ctx=91283, majf=0, minf=7 >> IO depths : 1=0.1%, 2=0.1%, 4=0.1%, 8=0.1%, 16=0.1%, 32=100.0%, >>> =64=0.0% >> submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >>> =64=0.0% >> complete : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.1%, 64=0.0%, >>> =64=0.0% >> issued : total=r=1310044/w=1309348/d=0, short=r=0/w=0/d=0 >> latency : target=0, window=0, percentile=100.00%, depth=32 >> >> Run status group 0 (all jobs): >> READ: io=5117.4MB, aggrb=148207KB/s, minb=148207KB/s, maxb=148207KB/s, >> mint=35357msec, maxt=35357msec >> WRITE: io=5114.7MB, aggrb=148128KB/s, minb=148128KB/s, maxb=148128KB/s, >> mint=35357msec, maxt=35357msec >> >> Disk stats (read/write): >> vdb: ios=1302512/1301780, merge=0/0, ticks=294828/407184, in_queue=701380, >> util=99.51% >> >> In my tests virtio-scsi shows worse results than virtio-blk. >> Host kernel 3.19-3, qemu-system-x86_64 -version >> QEMU emulator version 2.0.0. > > > Hi Konstantin, > > Thanks for sharing your test result with us! > > It is not surprising that virtio-blk performs better in such a test. It has a > much smaller command set, which results in both a simpler device model and > probably a simpler guest driver. > > virtio-scsi, on the other hand, provides more features and means to be more > scalable (you won't need to painfully mess with pci bridges to attach 1000 > disks). > > Anyway, we are working on improving virtio-scsi performance, although it's > theoretically impossible to make it faster or even equally fast. > > Regarding your test, I think with current code base, it generally performs > better if you use io=native. Have you compared that? > > Fam > Thank you for the answer! In my production system i'm interested to use io=thread, becouse i export MD raid1 devices to guest's and i need to read from the MD device performs balanced between raid1 legs (it's true only if io=thread). -- WBR Konstantin V. Krotov ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [Qemu-devel] virtio-blk and virtio-scsi performance comparison 2015-04-16 11:17 ` Konstantin Krotov @ 2015-04-16 11:57 ` Paolo Bonzini 2015-04-21 9:53 ` Konstantin Krotov 0 siblings, 1 reply; 7+ messages in thread From: Paolo Bonzini @ 2015-04-16 11:57 UTC (permalink / raw) To: kkv, Fam Zheng; +Cc: qemu-devel On 16/04/2015 13:17, Konstantin Krotov wrote: > In my production system i'm interested to use io=thread, becouse i > export MD raid1 devices to guest's and i need to read from the MD device > performs balanced between raid1 legs (it's true only if io=thread). Can you detail the problem more? That could be a kernel bug. Paolo ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [Qemu-devel] virtio-blk and virtio-scsi performance comparison 2015-04-16 11:57 ` Paolo Bonzini @ 2015-04-21 9:53 ` Konstantin Krotov 2015-04-21 9:57 ` Paolo Bonzini 0 siblings, 1 reply; 7+ messages in thread From: Konstantin Krotov @ 2015-04-21 9:53 UTC (permalink / raw) To: Paolo Bonzini, Fam Zheng; +Cc: qemu-devel 16.04.2015 14:57, Paolo Bonzini пишет: > > On 16/04/2015 13:17, Konstantin Krotov wrote: >> In my production system i'm interested to use io=thread, becouse i >> export MD raid1 devices to guest's and i need to read from the MD device >> performs balanced between raid1 legs (it's true only if io=thread). > > Can you detail the problem more? That could be a kernel bug. > > Paolo > I connect to the host system, two storage systems as block devices. Both block devices combine md-raid1. md-device use as disk for virtual machine. If i use io=native, read perform only from one of two raid1 legs. I'd like to distribute the load reading between two raid1 legs, but md-raid1 implementation it does only if set io=thread. -- WBR Konstantin V. Krotov ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [Qemu-devel] virtio-blk and virtio-scsi performance comparison 2015-04-21 9:53 ` Konstantin Krotov @ 2015-04-21 9:57 ` Paolo Bonzini 0 siblings, 0 replies; 7+ messages in thread From: Paolo Bonzini @ 2015-04-21 9:57 UTC (permalink / raw) To: kkv, Fam Zheng; +Cc: qemu-devel On 21/04/2015 11:53, Konstantin Krotov wrote: >> Can you detail the problem more? That could be a kernel bug. > > I connect to the host system, two storage systems as block devices. Both > block devices combine md-raid1. md-device use as disk for virtual > machine. If i use io=native, read perform only from one of two raid1 > legs. I'd like to distribute the load reading between two raid1 legs, > but md-raid1 implementation it does only if set io=thread. That looks like a kernel problem. Paolo ^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2015-04-21 9:57 UTC | newest] Thread overview: 7+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2015-04-15 8:17 [Qemu-devel] virtio-blk and virtio-scsi performance comparison Konstantin Krotov 2015-04-16 1:27 ` Fam Zheng 2015-04-16 8:04 ` Paolo Bonzini 2015-04-16 11:17 ` Konstantin Krotov 2015-04-16 11:57 ` Paolo Bonzini 2015-04-21 9:53 ` Konstantin Krotov 2015-04-21 9:57 ` Paolo Bonzini
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