Xen performance on guest with LV/SSD very low.

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frm
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Xen performance on guest with LV/SSD very low.

frm
Hi,

The past few days, I have scratched my head regarding very disk IO
performance on Xen.
I have installed KVM on the same machine, same result: very low disk IO.

With iozone on Dom0 I easily 180 MB/s, in a pv guest only 2MB/s. The Dom0 is
90 times faster.
I tried many things, but I can not find the solution:

OS dom0: 4.18.0-0.bpo.1-amd64
Xen: 4.11.1

Command line: loglvl=all dom0_mem=2048M dom0_max_vcpus=2 dom0_vcpus_pin
iommu=1 ucode=scan gnttab_max_frames=256

Guest:
OS: 4.18.0-0.bpo.1-amd64
lsmod | grep blk
xen_blkfront           40960  1

What am Ii missing here?

Thanks,

-- Jaap


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Re: Xen performance on guest with LV/SSD very low.

Mark Pryor
It appears you are on Stretch with a self-built xen-4.11.
Can you clarify if you have used `make debball` and installed from a *.deb?

and check that no remnants of a distro install are still present:
>dpkg -l | grep -P '^ii|^hi' | grep -P 'qemu|xen'

thanks,
PryMar56
##xen-packaging on Freenode IRC

On Sunday, December 23, 2018, 12:09:55 PM PST, <[hidden email]> wrote:


Hi,

The past few days, I have scratched my head regarding very disk IO
performance on Xen.
I have installed KVM on the same machine, same result: very low disk IO.

With iozone on Dom0 I easily 180 MB/s, in a pv guest only 2MB/s. The Dom0 is
90 times faster.
I tried many things, but I can not find the solution:

OS dom0: 4.18.0-0.bpo.1-amd64
Xen: 4.11.1

Command line: loglvl=all dom0_mem=2048M dom0_max_vcpus=2 dom0_vcpus_pin
iommu=1 ucode=scan gnttab_max_frames=256

Guest:
OS: 4.18.0-0.bpo.1-amd64
lsmod | grep blk
xen_blkfront          40960  1

What am Ii missing here?

Thanks,

-- Jaap


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frm
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Re: Xen performance on guest with LV/SSD very low.

frm

I am on stretch with a self compiled Xen to try to solve the problem.

Did

Make debball

And installed from the generated deb

 

>dpkg -l | grep -P '^ii|^hi' | grep -P 'qemu|xen'  results in

ii  grub-xen-bin                       2.02~beta3-5+deb9u1            amd64        GRand Unified Bootloader, version 2 (Xen binaries)

ii  grub-xen-host                      2.02~beta3-5+deb9u1            amd64        GRand Unified Bootloader, version 2 (Xen host version)

ii  ipxe-qemu                          1.0.0+git-20161027.b991c67-1   all          PXE boot firmware - ROM images for qemu

ii  qemu-system-common                 1:2.8+dfsg-6+deb9u5            amd64        QEMU full system emulation binaries (common files)

ii  qemu-utils                         1:2.8+dfsg-6+deb9u5            amd64        QEMU utilities

ii  xen-upstream                       4.11.1                         amd64        Xen upstream testing build snapshot

 

 

Van: Mark Pryor <[hidden email]>
Verzonden: Sunday, 23 December 2018 22:38
Aan: [hidden email]; [hidden email]
Onderwerp: Re: [Xen-users] Xen performance on guest with LV/SSD very low.

 

It appears you are on Stretch with a self-built xen-4.11.

Can you clarify if you have used `make debball` and installed from a *.deb?

 

and check that no remnants of a distro install are still present:
>dpkg -l | grep -P '^ii|^hi' | grep -P 'qemu|xen'

 

thanks,

PryMar56
##xen-packaging on Freenode IRC

 

On Sunday, December 23, 2018, 12:09:55 PM PST, <[hidden email]> wrote:

 

 

Hi,

 

The past few days, I have scratched my head regarding very disk IO

performance on Xen.

I have installed KVM on the same machine, same result: very low disk IO.

 

With iozone on Dom0 I easily 180 MB/s, in a pv guest only 2MB/s. The Dom0 is

90 times faster.

I tried many things, but I can not find the solution:

 

OS dom0: 4.18.0-0.bpo.1-amd64

Xen: 4.11.1

 

Command line: loglvl=all dom0_mem=2048M dom0_max_vcpus=2 dom0_vcpus_pin

iommu=1 ucode=scan gnttab_max_frames=256

 

Guest:

OS: 4.18.0-0.bpo.1-amd64

lsmod | grep blk

xen_blkfront          40960  1

 

What am Ii missing here?

 

Thanks,

 

-- Jaap

 

 

_______________________________________________

Xen-users mailing list


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frm
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Re: Xen performance on guest with LV/SSD very low.

frm

Problem solved.

 

Using the mount option sync in /etc/fstab on guests is not good for performance if you are using a SSD.

Now used async as mount option and achieving near native performance.

 

Van: Xen-users <[hidden email]> Namens [hidden email]
Verzonden: Sunday, 23 December 2018 23:30
Aan: 'Mark Pryor' <[hidden email]>; [hidden email]; [hidden email]
Onderwerp: Re: [Xen-users] Xen performance on guest with LV/SSD very low.

 

I am on stretch with a self compiled Xen to try to solve the problem.

Did

Make debball

And installed from the generated deb

 

>dpkg -l | grep -P '^ii|^hi' | grep -P 'qemu|xen'  results in

ii  grub-xen-bin                       2.02~beta3-5+deb9u1            amd64        GRand Unified Bootloader, version 2 (Xen binaries)

ii  grub-xen-host                      2.02~beta3-5+deb9u1            amd64        GRand Unified Bootloader, version 2 (Xen host version)

ii  ipxe-qemu                          1.0.0+git-20161027.b991c67-1   all          PXE boot firmware - ROM images for qemu

ii  qemu-system-common                 1:2.8+dfsg-6+deb9u5            amd64        QEMU full system emulation binaries (common files)

ii  qemu-utils                         1:2.8+dfsg-6+deb9u5            amd64        QEMU utilities

ii  xen-upstream                       4.11.1                         amd64        Xen upstream testing build snapshot

 

 

Van: Mark Pryor <[hidden email]>
Verzonden: Sunday, 23 December 2018 22:38
Aan: [hidden email]; [hidden email]
Onderwerp: Re: [Xen-users] Xen performance on guest with LV/SSD very low.

 

It appears you are on Stretch with a self-built xen-4.11.

Can you clarify if you have used `make debball` and installed from a *.deb?

 

and check that no remnants of a distro install are still present:
>dpkg -l | grep -P '^ii|^hi' | grep -P 'qemu|xen'

 

thanks,

PryMar56
##xen-packaging on Freenode IRC

 

On Sunday, December 23, 2018, 12:09:55 PM PST, <[hidden email]> wrote:

 

 

Hi,

 

The past few days, I have scratched my head regarding very disk IO

performance on Xen.

I have installed KVM on the same machine, same result: very low disk IO.

 

With iozone on Dom0 I easily 180 MB/s, in a pv guest only 2MB/s. The Dom0 is

90 times faster.

I tried many things, but I can not find the solution:

 

OS dom0: 4.18.0-0.bpo.1-amd64

Xen: 4.11.1

 

Command line: loglvl=all dom0_mem=2048M dom0_max_vcpus=2 dom0_vcpus_pin

iommu=1 ucode=scan gnttab_max_frames=256

 

Guest:

OS: 4.18.0-0.bpo.1-amd64

lsmod | grep blk

xen_blkfront          40960  1

 

What am Ii missing here?

 

Thanks,

 

-- Jaap

 

 

_______________________________________________

Xen-users mailing list


_______________________________________________
Xen-users mailing list
[hidden email]
https://lists.xenproject.org/mailman/listinfo/xen-users