Re: [Qemu-devel] Re: [RFC][PATCH] make sure disk writes actually hit disk

[Paul Brook]

> > Have you measured the impact of O_SYNC? I wouldn't be surprised if it was
> > significant.
>
> I suspect it'll be horrific in the qemu codebase (blocking execution
> of the guest OS until disk IO is complete), but it's fine in the Xen
> qemu-dm situation, where IO completion happens asynchronously.
>
> The recent commit message on the Xen side did not suggest there was
> that much of a difference between both qemu code bases.  Obviously
> I was wrong, and the O_SYNC bandaid should probably be kept out for
> now.

Ah, ok. I didn't realise they'd diverged that much either.

Paul