Re: [ANNOUNCE] Native Linux KVM tool v2

[Prasad Joshi <prasadjoshi124@gmail.com>]

On Wed, Jun 15, 2011 at 6:10 PM, Pekka Enberg <penberg@kernel.org> wrote:
> On Wed, Jun 15, 2011 at 7:30 PM, Avi Kivity <avi@redhat.com> wrote:
>> On 06/15/2011 06:53 PM, Pekka Enberg wrote:
>>>
>>> - Fast QCOW2 image read-write support beating Qemu in fio benchmarks. See
>>> the
>>>   following URL for test result details: https://gist.github.com/1026888
>>
>> This is surprising.  How is qemu invoked?
>
> Prasad will have the details. Please note that the above are with Qemu
> defaults which doesn't use virtio. The results with virtio are little
> better but still in favor of tools/kvm.
>

The qcow2 image used for testing was copied on to /dev/shm to avoid
the disk delays in performance measurement.

QEMU was invoked with following parameters

$ qemu-system-x86_64 -hda <disk image on hard disk> -hdb
/dev/shm/test.qcow2 -m 1024M

FIO job file used for measuring the numbers was

prasad@prasad-vm:~$ cat fio-mixed.job
; fio-mixed.job for autotest

[global]
name=fio-sync
directory=/mnt
rw=randrw
rwmixread=67
rwmixwrite=33
bsrange=16K-256K
direct=0
end_fsync=1
verify=crc32
;ioscheduler=x
numjobs=4

[file1]
size=50M
ioengine=sync
mem=malloc

[file2]
stonewall
size=50M
ioengine=aio
mem=shm
iodepth=4

[file3]
stonewall
size=50M
ioengine=mmap
mem=mmap
direct=1

[file4]
stonewall
size=50M
ioengine=splice
mem=malloc
direct=1

- The test generates 16 file each of ~50MB, so in total ~800MB data was written.
- The test.qcow2 was newly created before it was used with QEMU or KVM tool
- The size of the QCOW2 image was 1.5GB.
- The host machine had 2GB RAM.
- The guest machine in both the cases was started with 1GB memory.

Thanks and Regards,
Prasad

>> btw the dump above is a little hard to interpret.
>
> It's what fio reports. The relevant bits are:
>
>
> Qemu:
>
> Run status group 0 (all jobs):
>  READ: io=204800KB, aggrb=61152KB/s, minb=15655KB/s, maxb=17845KB/s,
> mint=2938msec, maxt=3349msec
>  WRITE: io=68544KB, aggrb=28045KB/s, minb=6831KB/s, maxb=7858KB/s,
> mint=2292msec, maxt=2444msec
>
> Run status group 1 (all jobs):
>  READ: io=204800KB, aggrb=61779KB/s, minb=15815KB/s, maxb=17189KB/s,
> mint=3050msec, maxt=3315msec
>  WRITE: io=66576KB, aggrb=24165KB/s, minb=6205KB/s, maxb=7166KB/s,
> mint=2485msec, maxt=2755msec
>
> Run status group 2 (all jobs):
>  READ: io=204800KB, aggrb=6722KB/s, minb=1720KB/s, maxb=1737KB/s,
> mint=30178msec, maxt=30467msec
>  WRITE: io=65424KB, aggrb=2156KB/s, minb=550KB/s, maxb=573KB/s,
> mint=29682msec, maxt=30342msec
>
> Run status group 3 (all jobs):
>  READ: io=204800KB, aggrb=6994KB/s, minb=1790KB/s, maxb=1834KB/s,
> mint=28574msec, maxt=29279msec
>  WRITE: io=68192KB, aggrb=2382KB/s, minb=548KB/s, maxb=740KB/s,
> mint=27121msec, maxt=28625msec
>
> Disk stats (read/write):
>  sdb: ios=60583/6652, merge=0/164, ticks=156340/672030,
> in_queue=828230, util=82.71%
>
> tools/kvm:
>
> Run status group 0 (all jobs):
>   READ: io=204800KB, aggrb=149162KB/s, minb=38185KB/s,
> maxb=46030KB/s, mint=1139msec, maxt=1373msec
>  WRITE: io=70528KB, aggrb=79156KB/s, minb=18903KB/s, maxb=23726KB/s,
> mint=804msec, maxt=891msec
>
> Run status group 1 (all jobs):
>   READ: io=204800KB, aggrb=188235KB/s, minb=48188KB/s,
> maxb=57932KB/s, mint=905msec, maxt=1088msec
>  WRITE: io=64464KB, aggrb=84821KB/s, minb=21751KB/s, maxb=27392KB/s,
> mint=570msec, maxt=760msec
>
> Run status group 2 (all jobs):
>   READ: io=204800KB, aggrb=20005KB/s, minb=5121KB/s, maxb=5333KB/s,
> mint=9830msec, maxt=10237msec
>  WRITE: io=66624KB, aggrb=6615KB/s, minb=1671KB/s, maxb=1781KB/s,
> mint=9558msec, maxt=10071msec
>
> Run status group 3 (all jobs):
>   READ: io=204800KB, aggrb=66149KB/s, minb=16934KB/s, maxb=17936KB/s,
> mint=2923msec, maxt=3096msec
>  WRITE: io=69600KB, aggrb=26717KB/s, minb=6595KB/s, maxb=7342KB/s,
> mint=2530msec, maxt=2605msec
>
> Disk stats (read/write):
>  vdb: ios=61002/6654, merge=0/183, ticks=27270/205780,
> in_queue=232220, util=69.46%
>