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Re: [Qemu-devel] xen_disk qdevification
From: |
Markus Armbruster |
Subject: |
Re: [Qemu-devel] xen_disk qdevification |
Date: |
Mon, 05 Nov 2018 16:57:31 +0100 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) |
Paul Durrant <address@hidden> writes:
>> -----Original Message-----
>> From: Kevin Wolf [mailto:address@hidden
>> Sent: 02 November 2018 11:04
>> To: Tim Smith <address@hidden>
>> Cc: address@hidden; address@hidden; qemu-
>> address@hidden; Anthony Perard <address@hidden>; Paul Durrant
>> <address@hidden>; Stefano Stabellini <address@hidden>;
>> Max Reitz <address@hidden>; address@hidden
>> Subject: xen_disk qdevification (was: [PATCH 0/3] Performance improvements
>> for xen_disk v2)
>>
>> Am 02.11.2018 um 11:00 hat Tim Smith geschrieben:
>> > A series of performance improvements for disks using the Xen PV ring.
>> >
>> > These have had fairly extensive testing.
>> >
>> > The batching and latency improvements together boost the throughput
>> > of small reads and writes by two to six percent (measured using fio
>> > in the guest)
>> >
>> > Avoiding repeated calls to posix_memalign() reduced the dirty heap
>> > from 25MB to 5MB in the case of a single datapath process while also
>> > improving performance.
>> >
>> > v2 removes some checkpatch complaints and fixes the CCs
>>
>> Completely unrelated, but since you're the first person touching
>> xen_disk in a while, you're my victim:
>>
>> At KVM Forum we discussed sending a patch to deprecate xen_disk because
>> after all those years, it still hasn't been converted to qdev. Markus is
>> currently fixing some other not yet qdevified block device, but after
>> that xen_disk will be the only one left.
>>
>> A while ago, a downstream patch review found out that there are some QMP
>> commands that would immediately crash if a xen_disk device were present
>> because of the lacking qdevification. This is not the code quality
>> standard I envision for QEMU. It's time for non-qdev devices to go.
>>
>> So if you guys are still interested in the device, could someone please
>> finally look into converting it?
>>
>
> I have a patch series to do exactly this. It's somewhat involved as I
> need to convert the whole PV backend infrastructure. I will try to
> rebase and clean up my series a.s.a.p.
Awesome! Please coordinate with Anthony Prerard to avoid duplicating
work if you haven't done so already.
- Re: [Qemu-devel] [PATCH 3/3] Avoid repeated memory allocation in xen_disk, (continued)
- [Qemu-devel] [PATCH 2/3] Improve xen_disk response latency, Tim Smith, 2018/11/02
- [Qemu-devel] [PATCH 1/3] Improve xen_disk batching behaviour, Tim Smith, 2018/11/02
- [Qemu-devel] xen_disk qdevification (was: [PATCH 0/3] Performance improvements for xen_disk v2), Kevin Wolf, 2018/11/02
- Re: [Qemu-devel] xen_disk qdevification (was: [PATCH 0/3] Performance improvements for xen_disk v2), Paul Durrant, 2018/11/02
- Re: [Qemu-devel] xen_disk qdevification (was: [PATCH 0/3] Performance improvements for xen_disk v2), Kevin Wolf, 2018/11/02
- Re: [Qemu-devel] xen_disk qdevification,
Markus Armbruster <=
- Re: [Qemu-devel] xen_disk qdevification, Paul Durrant, 2018/11/05
- Re: [Qemu-devel] xen_disk qdevification, Paul Durrant, 2018/11/08
- Re: [Qemu-devel] xen_disk qdevification, Kevin Wolf, 2018/11/08
- Re: [Qemu-devel] xen_disk qdevification, Paul Durrant, 2018/11/08
- Re: [Qemu-devel] xen_disk qdevification, Paul Durrant, 2018/11/08
- Re: [Qemu-devel] xen_disk qdevification, Paul Durrant, 2018/11/09
- Re: [Qemu-devel] xen_disk qdevification, Kevin Wolf, 2018/11/09