From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
To: John Morrison <john@clustered.net>
Cc: xen-devel@lists.xen.org
Subject: Re: Disk iops performance scalability
Date: Tue, 19 Mar 2013 08:58:03 -0400 [thread overview]
Message-ID: <20130319125802.GA2706@phenom.dumpdata.com> (raw)
In-Reply-To: <5B6A896C-D23D-49E1-8214-A5E63D190620@clustered.net>
On Mon, Mar 18, 2013 at 11:23:00PM +0000, John Morrison wrote:
> Hi,
>
> Seeing a drop-off in iops when more vcpu's are added:-
>
> 3.8.2 kernel/xen-4.2.1/single domU/LVM backend/8GB RAM domU/2GB RAM dom0
>
> dom0_max_vcpus=2 dom0_vcpus_pin
>
> domU 8 cores fio result 145k iops
> domU 10 cores fio result 99k iops
> domU 12 cores fio result 89k iops
> domU 14 cores fio result 81k iops
>
> ioping . -c 3
> 4096 bytes from . (ext4 /dev/xvda1): request=1 time=0.1 ms
> 4096 bytes from . (ext4 /dev/xvda1): request=2 time=0.7 ms
> 4096 bytes from . (ext4 /dev/xvda1): request=3 time=0.8 ms
>
> --- . (ext4 /dev/xvda1) ioping statistics ---
> 3 requests completed in 2002.0 ms, 1836 iops, 7.2 mb/s
> min/avg/max/mdev = 0.1/0.5/0.8/0.3 ms
>
> The initial ioping response is good, then a lot of latency with later ones. Any ideas ?
Is your guest compiled with PARAVIRT_SPINLOCK and are you using a PV or PVHVM guest?
>
> Thanks
>
> John
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xen.org
> http://lists.xen.org/xen-devel
>
next prev parent reply other threads:[~2013-03-19 12:58 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-18 23:23 Disk iops performance scalability John Morrison
2013-03-19 12:58 ` Konrad Rzeszutek Wilk [this message]
2013-03-19 22:11 ` John Morrison
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