Re: Question about performance comparison between virtio-fs and virtio-blk

[Vivek Goyal]

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

> 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