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Re: [Qemu-devel] poor virtio-scsi performance (fio testing)
From: |
Alexandre DERUMIER |
Subject: |
Re: [Qemu-devel] poor virtio-scsi performance (fio testing) |
Date: |
Wed, 25 Nov 2015 11:27:03 +0100 (CET) |
>>I'm try with classic lvm - sometimes i get more iops, but stable
results is the same =)
I have tested with a raw file, qemu 2.4 + virtio-scsi (without iothread), I'm
around 25k iops
with an intel ssd 3500. (host cpu are xeon v3 3,1ghz)
randrw: (g=0): rw=randrw, bs=4K-4K/4K-4K/4K-4K, ioengine=libaio, iodepth=32
...
fio-2.1.11
Starting 10 processes
Jobs: 4 (f=3): [m(2),_(3),m(1),_(3),m(1)] [100.0% done] [96211KB/96639KB/0KB
/s] [24.6K/24.2K/0 iops] [eta 00m:00s]
randrw: (groupid=0, jobs=10): err= 0: pid=25662: Wed Nov 25 11:25:22 2015
read : io=5124.7MB, bw=97083KB/s, iops=24270, runt= 54047msec
slat (usec): min=1, max=34577, avg=181.90, stdev=739.20
clat (usec): min=177, max=49641, avg=6511.31, stdev=3176.16
lat (usec): min=185, max=52810, avg=6693.55, stdev=3247.36
clat percentiles (usec):
| 1.00th=[ 1704], 5.00th=[ 2576], 10.00th=[ 3184], 20.00th=[ 4016],
| 30.00th=[ 4704], 40.00th=[ 5344], 50.00th=[ 5984], 60.00th=[ 6688],
| 70.00th=[ 7456], 80.00th=[ 8512], 90.00th=[10304], 95.00th=[12224],
| 99.00th=[17024], 99.50th=[19584], 99.90th=[26240], 99.95th=[29568],
| 99.99th=[37632]
bw (KB /s): min= 6690, max=12432, per=10.02%, avg=9728.49, stdev=796.49
write: io=5115.1MB, bw=96929KB/s, iops=24232, runt= 54047msec
slat (usec): min=1, max=37270, avg=188.68, stdev=756.21
clat (usec): min=98, max=54737, avg=6246.50, stdev=3078.27
lat (usec): min=109, max=56078, avg=6435.53, stdev=3134.23
clat percentiles (usec):
| 1.00th=[ 1960], 5.00th=[ 2640], 10.00th=[ 3120], 20.00th=[ 3856],
| 30.00th=[ 4512], 40.00th=[ 5088], 50.00th=[ 5664], 60.00th=[ 6304],
| 70.00th=[ 7072], 80.00th=[ 8160], 90.00th=[ 9920], 95.00th=[11712],
| 99.00th=[16768], 99.50th=[19328], 99.90th=[26496], 99.95th=[31104],
| 99.99th=[42752]
bw (KB /s): min= 7424, max=12712, per=10.02%, avg=9712.21, stdev=768.32
lat (usec) : 100=0.01%, 250=0.01%, 500=0.02%, 750=0.03%, 1000=0.05%
lat (msec) : 2=1.49%, 4=19.18%, 10=68.69%, 20=10.10%, 50=0.45%
lat (msec) : 100=0.01%
cpu : usr=1.28%, sys=8.94%, ctx=329299, majf=0, minf=76
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=1311760/w=1309680/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=5124.7MB, aggrb=97082KB/s, minb=97082KB/s, maxb=97082KB/s,
mint=54047msec, maxt=54047msec
WRITE: io=5115.1MB, aggrb=96928KB/s, minb=96928KB/s, maxb=96928KB/s,
mint=54047msec, maxt=54047msec
Disk stats (read/write):
sdb: ios=1307835/1305417, merge=2523/2770, ticks=4309296/3954628,
in_queue=8274916, util=99.95%
----- Mail original -----
De: "Vasiliy Tolstov" <address@hidden>
À: "aderumier" <address@hidden>
Cc: "qemu-devel" <address@hidden>
Envoyé: Mercredi 25 Novembre 2015 11:12:33
Objet: Re: [Qemu-devel] poor virtio-scsi performance (fio testing)
2015-11-25 13:08 GMT+03:00 Alexandre DERUMIER <address@hidden>:
> Maybe could you try to create 2 disk in your vm, each with 1 dedicated
> iothread,
>
> then try to run fio on both disk at the same time, and see if performance
> improve.
>
Thats fine, but by default i have only one disk inside vm, so i prefer
increase single disk speed.
>
> But maybe they are some write overhead with lvmthin (because of copy on
> write) and sheepdog.
>
> Do you have tried with classic lvm or raw file ?
I'm try with classic lvm - sometimes i get more iops, but stable
results is the same =)
--
Vasiliy Tolstov,
e-mail: address@hidden