Re: FreeBSD 10.1 disk performance lower than identical Linux Guest
On Sat, Feb 21, 2015 at 06:59:23PM +, Greg Langford wrote: > I am running CentOS 6.6 x86_64 as a KVM host and have a number of > guests running. > > After some experimenting I have noticed something curious, FreeBSD > disk performance seems to be just over half of that of a Linux guest > with an identical configuration. > > From my understanding virtio is included in FreeBSD 10.0 onwards. > > My CentOS guest has approx 130MB/s when using dd to read /dev/zero and > write it to a file on the guest file system. This is about the same > when doing the same on the hypervisor it's self. The stats are gained > using iotop on the hypervisor while the test is performed. > > However the FreeBSD guest gets about 70MB/s maximum when performing > the same test and is running FreeBSD 10.1 > > Has anyone seen this before, is it a known issue or expected > behaviour? I have been scratching my head about it for a number of > days now. Please post the dd command-line and the QEMU command-lines for launching the Linux and FreeBSD guests. Stefan pgpiFqMmCaeyl.pgp Description: PGP signature
Re: FreeBSD 10.1 disk performance lower than identical Linux Guest
On Sat, Feb 21, 2015 at 7:59 PM, Greg Langford wrote: > Good Evening, Hi Greg, > > I am running CentOS 6.6 x86_64 as a KVM host and have a number of > guests running. > > After some experimenting I have noticed something curious, FreeBSD > disk performance seems to be just over half of that of a Linux guest > with an identical configuration. > > From my understanding virtio is included in FreeBSD 10.0 onwards. > > My CentOS guest has approx 130MB/s when using dd to read /dev/zero and > write it to a file on the guest file system. This is about the same > when doing the same on the hypervisor it's self. The stats are gained > using iotop on the hypervisor while the test is performed. > > However the FreeBSD guest gets about 70MB/s maximum when performing > the same test and is running FreeBSD 10.1 > > Has anyone seen this before, is it a known issue or expected > behaviour? I have been scratching my head about it for a number of > days now. There have been some performance improvements to the FreeBSD virtio-blk driver in -CURRENT: https://github.com/freebsd/freebsd/commit/6e8ba9083acb Maybe these help? > > Best Regards, > Greg Langford Kind regards, Ruben Kerkhof -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
FreeBSD 10.1 disk performance lower than identical Linux Guest
Good Evening, I am running CentOS 6.6 x86_64 as a KVM host and have a number of guests running. After some experimenting I have noticed something curious, FreeBSD disk performance seems to be just over half of that of a Linux guest with an identical configuration. >From my understanding virtio is included in FreeBSD 10.0 onwards. My CentOS guest has approx 130MB/s when using dd to read /dev/zero and write it to a file on the guest file system. This is about the same when doing the same on the hypervisor it's self. The stats are gained using iotop on the hypervisor while the test is performed. However the FreeBSD guest gets about 70MB/s maximum when performing the same test and is running FreeBSD 10.1 Has anyone seen this before, is it a known issue or expected behaviour? I have been scratching my head about it for a number of days now. Best Regards, Greg Langford -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
