Re: [Xen-devel] [PATCH RFC v2 0/5] Multi-queue support for xen-blkfront and xen-blkback

[Bob Liu <bob.liu@xxxxxxxxxx>]

On 06/30/2015 10:21 PM, Marcus Granado wrote:
> On 13/05/15 11:29, Bob Liu wrote:
>>
>> On 04/28/2015 03:46 PM, Arianna Avanzini wrote:
>>> Hello Christoph,
>>>
>>> Il 28/04/2015 09:36, Christoph Hellwig ha scritto:
>>>> What happened to this patchset?
>>>>
>>>
>>> It was passed on to Bob Liu, who published a follow-up patchset here: 
>>> https://lkml.org/lkml/2015/2/15/46
>>>
>>
>> Right, and then I was interrupted by another xen-block feature: 'multi-page' 
>> ring.
>> Will back on this patchset soon. Thank you!
>>
>> -Bob
>>
> 
> Hi,
> 
> Our measurements for the multiqueue patch indicate a clear improvement in 
> iops when more queues are used.
> 
> The measurements were obtained under the following conditions:
> 
> - using blkback as the dom0 backend with the multiqueue patch applied to a 
> dom0 kernel 4.0 on 8 vcpus.
> 
> - using a recent Ubuntu 15.04 kernel 3.19 with multiqueue frontend applied to 
> be used as a guest on 4 vcpus
> 
> - using a micron RealSSD P320h as the underlying local storage on a Dell 
> PowerEdge R720 with 2 Xeon E5-2643 v2 cpus.
> 
> - fio 2.2.7-22-g36870 as the generator of synthetic loads in the guest. We 
> used direct_io to skip caching in the guest and ran fio for 60s reading a 
> number of block sizes ranging from 512 bytes to 4MiB. Queue depth of 32 for 
> each queue was used to saturate individual vcpus in the guest.
> 
> We were interested in observing storage iops for different values of block 
> sizes. Our expectation was that iops would improve when increasing the number 
> of queues, because both the guest and dom0 would be able to make use of more 
> vcpus to handle these requests.
> 
> These are the results (as aggregate iops for all the fio threads) that we got 
> for the conditions above with sequential reads:
> 
> fio_threads  io_depth  block_size   1-queue_iops  8-queue_iops
>     8           32       512           158K         264K
>     8           32        1K           157K         260K
>     8           32        2K           157K         258K
>     8           32        4K           148K         257K
>     8           32        8K           124K         207K
>     8           32       16K            84K         105K
>     8           32       32K            50K          54K
>     8           32       64K            24K          27K
>     8           32      128K            11K          13K
> 
> 8-queue iops was better than single queue iops for all the block sizes. There 
> were very good improvements as well for sequential writes with block size 4K 
> (from 80K iops with single queue to 230K iops with 8 queues), and no 
> regressions were visible in any measurement performed.
> 

Great! Thank you very much for the test.

I'm trying to rebase these patches to the latest kernel version(v4.1) and will 
send out in following days.

-- 
Regards,
-Bob

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