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Posted to commits@cloudstack.apache.org by GitBox <gi...@apache.org> on 2021/03/31 09:16:45 UTC
[GitHub] [cloudstack] wido opened a new issue #4883: KVM: Add io driver option to libvirt XML for io_uring support
wido opened a new issue #4883:
URL: https://github.com/apache/cloudstack/issues/4883
##### ISSUE TYPE
* Feature Idea
##### COMPONENT NAME
~~~
KVM
~~~
##### CLOUDSTACK VERSION
~~~
master
~~~
##### SUMMARY
~~~
ouring is a new kernel asynchronous I/O processing mechanism proposed as a much faster alternative for conventional Linux AIO. Patches were merged in Linux 5.1 and gave a promised performance boost. We decided to integrate it into QEMU to make virtualized storage devices work more efficiently. Let's take a look at how iouring works in QEMU.
~~~
Source:
- https://www.phoronix.com/scan.php?page=news_item&px=KVM-IO-uring-Passthrough-LF2020
- https://archive.fosdem.org/2020/schedule/event/vai_io_uring_in_qemu/
By using io_uring with Qemu we can see a massive I/O performance improvement within Virtual Machines running from Local and/or NFS storage.
In order to use this we need:
- Qemu >= 5.0
- Libvirt >= 6.3.0
We then need to add this to the XML definition for libvirt which would then look like:
~~~
<disk type='file' device='disk'>
<driver name='qemu' type='qcow2' cache='writeback' discard='unmap' io='io_uring'/>
<source file='/var/lib/libvirt/images/a0f677c6-b065-4795-b468-2b5974496c75'/>
<backingStore/>
<target dev='sda' bus='scsi'/>
<serial>a0f677c6b0654795b468</serial>
<alias name='scsi0-0-0-0'/>
<address type='drive' controller='0' bus='0' target='0' unit='0'/>
</disk>
~~~
With io_uring I/O performance can improve drastically and reach near bare-metal performance.
Currently there is no Qemu version in a stable Ubuntu nor CentOS release, but we can already merge this in master so that when this is released we can use it.
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[GitHub] [cloudstack] GabrielBrascher commented on issue #4883: KVM: Add io driver option to libvirt XML for io_uring support
Posted by GitBox <gi...@apache.org>.
GabrielBrascher commented on issue #4883:
URL: https://github.com/apache/cloudstack/issues/4883#issuecomment-812556472
@DaanHoogland to give some taste of the draft here follows the first commit https://github.com/PCextreme/cloudstack/commit/c7c3dd3dd9b8869f45c5bd9c17af83d230ac7886
:warning:warning: work-in-progress :slightly_smiling_face:
As @wido mentioned, we can check the libvirt/qemu versions via the cloudstack-agent service that is running on the KVM node.
```
if(_hypervisorLibvirtVersion >= 6030000 && _hypervisorQemuVersion >= 5000000) {
disk.setIoDriver(DiskDef.IoDriver.IOURING);
}
```
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[GitHub] [cloudstack] rhtyd commented on issue #4883: KVM: Add io driver option to libvirt XML for io_uring support
Posted by GitBox <gi...@apache.org>.
rhtyd commented on issue #4883:
URL: https://github.com/apache/cloudstack/issues/4883#issuecomment-880466620
Merged in https://github.com/apache/cloudstack/pull/5012
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[GitHub] [cloudstack] DaanHoogland commented on issue #4883: KVM: Add io driver option to libvirt XML for io_uring support
Posted by GitBox <gi...@apache.org>.
DaanHoogland commented on issue #4883:
URL: https://github.com/apache/cloudstack/issues/4883#issuecomment-813929100
looks good so far, but my question about application architecture is only now getting clear to myself: will the knowledge be in the orchestrations layer, or will it be purely a provisioning (agent side) matter? I.E. do we want the opreator to be able to "sell" this to the users?
thanks guys
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[GitHub] [cloudstack] DaanHoogland commented on issue #4883: KVM: Add io driver option to libvirt XML for io_uring support
Posted by GitBox <gi...@apache.org>.
DaanHoogland commented on issue #4883:
URL: https://github.com/apache/cloudstack/issues/4883#issuecomment-813994689
ok, so no sellable item, just cloud wide support if available on host or not. thanks.
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[GitHub] [cloudstack] wido commented on issue #4883: KVM: Add io driver option to libvirt XML for io_uring support
Posted by GitBox <gi...@apache.org>.
wido commented on issue #4883:
URL: https://github.com/apache/cloudstack/issues/4883#issuecomment-813955599
> looks good so far, but my question about application architecture is only now getting clear to myself: will the knowledge be in the orchestrations layer, or will it be purely a provisioning (agent side) matter? I.E. do we want the opreator to be able to "sell" this to the users?
> thanks guys
This will be in the agent side (provisioning). It will be turned on if supported. This then makes sure the VM gets more I/O performance.
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[GitHub] [cloudstack] rhtyd closed issue #4883: KVM: Add io driver option to libvirt XML for io_uring support
Posted by GitBox <gi...@apache.org>.
rhtyd closed issue #4883:
URL: https://github.com/apache/cloudstack/issues/4883
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[GitHub] [cloudstack] GabrielBrascher commented on issue #4883: KVM: Add io driver option to libvirt XML for io_uring support
Posted by GitBox <gi...@apache.org>.
GabrielBrascher commented on issue #4883:
URL: https://github.com/apache/cloudstack/issues/4883#issuecomment-838523087
PR #5012 is out, for now as a draft.
To ilustrate, here follows an example of what `io_uring` can achive according to this presentation done at the KVM Forum 2020:
Credits to: https://static.sched.com/hosted_files/osseu2020/c8/KVMForum_2020_io_uring_passthrough_Stefano_Garzarella.pdf
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[GitHub] [cloudstack] wido commented on issue #4883: KVM: Add io driver option to libvirt XML for io_uring support
Posted by GitBox <gi...@apache.org>.
wido commented on issue #4883:
URL: https://github.com/apache/cloudstack/issues/4883#issuecomment-812516562
> looks like a minor change @wido , but will qemu/libvirt trip over the additional attribute if it is not yet supported, I.E. do we need an operator the set a switch and be intelligent about it? and can we query this per host (in case of a slow transition of a big env)?
It is very small indeed. @GabrielBrascher already started to work on this. Based on the Qemu and Libvirt version this is added or not.
In this case we can query this per host.
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[GitHub] [cloudstack] GabrielBrascher edited a comment on issue #4883: KVM: Add io driver option to libvirt XML for io_uring support
Posted by GitBox <gi...@apache.org>.
GabrielBrascher edited a comment on issue #4883:
URL: https://github.com/apache/cloudstack/issues/4883#issuecomment-812556472
@DaanHoogland to give some taste of the draft here follows the first commit https://github.com/PCextreme/cloudstack/commit/c7c3dd3dd9b8869f45c5bd9c17af83d230ac7886
:warning:warning: work-in-progress :slightly_smiling_face:
As @wido mentioned, we can check the libvirt/qemu versions via the cloudstack-agent service that is running on the KVM node.
Example:
```
if(_hypervisorLibvirtVersion >= 6030000 && _hypervisorQemuVersion >= 5000000) {
disk.setIoDriver(DiskDef.IoDriver.IOURING);
}
```
--
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[GitHub] [cloudstack] DaanHoogland commented on issue #4883: KVM: Add io driver option to libvirt XML for io_uring support
Posted by GitBox <gi...@apache.org>.
DaanHoogland commented on issue #4883:
URL: https://github.com/apache/cloudstack/issues/4883#issuecomment-812479192
looks like a minor change @wido , but will qemu/libvirt trip over the additional attribute if it is not yet supported, I.E. do we need an operator the set a switch and be intelligent about it? and can we query this per host (in case of a slow transition of a big env)?
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