Re: [Qemu-block] [PATCH 0/7] qcow2: Reduce the number of I/O ops when doing COW

[Anton Nefedov]

On 05/24/2017 07:20 PM, Alberto Garcia wrote:
> On Wed 24 May 2017 06:09:42 PM CEST, Anton Nefedov wrote:
>
> > I agree; as mentioned we have similar patches and they don't conflict
> > much.  We noticed a performance regression on HDD though, for the
> > presumably optimized case (random 4k write over a large backed image);
> > so the patches were put on hold.
>
> Interesting, I think that scenario was noticeably faster in my
> tests. What cluster size(s) and image size(s) were you using?
64k cluster, 2g image, write 32m in portions of 4k at random offsets

/Anton