Re: virtiofs vs 9p performance

[Christian Schoenebeck]

On Freitag, 25. September 2020 00:10:23 CEST Vivek Goyal wrote:
> In my testing, with cache=none, virtiofs performed better than 9p in
> all the fio jobs I was running. For the case of cache=auto  for virtiofs
> (with xattr enabled), 9p performed better in certain write workloads. I
> have identified root cause of that problem and working on
> HANDLE_KILLPRIV_V2 patches to improve WRITE performance of virtiofs
> with cache=auto and xattr enabled.

Please note, when it comes to performance aspects, you should set a reasonable 
high value for 'msize' on 9p client side:
https://wiki.qemu.org/Documentation/9psetup#msize

I'm also working on performance optimizations for 9p BTW. There is plenty of 
headroom to put it mildly. For QEMU 5.2 I started by addressing readdir 
requests:
https://wiki.qemu.org/ChangeLog/5.2#9pfs

Best regards,
Christian Schoenebeck