[Virtio-fs] Question about performance comparison between virtio-fs and virtio-blk

[Hao Xu]

On 7/26/22 21:17, Vivek Goyal wrote:
> On Tue, Jul 26, 2022 at 08:55:38AM -0400, Stefan Hajnoczi wrote:
>> On Tue, 26 Jul 2022 at 08:24, Hao Xu <hao.xu at linux.dev> wrote:
>>> I watched your presentation about virtiofs in 2020,
>>>
>>> https://www.youtube.com/watch?v=EIVOzTsGMMI&t=232s
>>>
>>> which is really helpful to me, but I have a question about the graph at
>>> 3:53, could you give
>>>
>>> me more info about the test, like what tool you use for the test, if
>>> it's fio, what is the parameters.
>>>
>>> I used fio to do randread test in a qemu box, but turns out the iops of
>>> virtio-blk and virtio-fs are similar.
>>
> 
> Hi Hao,
> 
> My impression in general is that virtio-blk is much faster than virtiofs.

When testing virtio-blk, did you use the device directly or mount it and
test against a file.

> A simple macro test is do a kernel compilation and compare time taken
> between the two.

Good idea, I just tested with single file.

Thanks,
Hao

> 
>> I have CCed Vivek Goyal, who has done more virtiofs benchmarking and
>> might have ideas to share.
>>
>> The benchmarking tool was fio with the stated blocksize and I/O
>> pattern. The benchmark was probably run with direct=1. Based on the
>> virtio-blk numbers I think iodepth was greater than 1 but I don't have
>> the exact fio job parameters.
> 
> I had basically used fio jobs. I wrote some simple wrapper scripts to
> run fio and parse and report numbers.
> 
> https://github.com/rhvgoyal/virtiofs-tests
> 
> I don't have data for virtio-blk but I do seem to have some comparison
> numbers of virtiofs and virtio-9p.
> 
> https://github.com/rhvgoyal/virtiofs-tests/tree/master/performance-results/feb-23-2021
> 
> Thanks
> Vivek
> 
>