Re: [RFC] extending splice for copy offloading

Miklos Szeredi
2013-09-26T19:53:22Z

On Thu, Sep 26, 2013 at 9:06 PM, Zach Brown <zab@redhat.com> wrote:

>> But I'm not sure it's worth the effort; 99% of the use of this
>> interface will be copying whole files. And for that perhaps we need a
>> different API, one which has been discussed some time ago:
>> asynchronous copyfile() returns immediately with a pollable event
>> descriptor indicating copy progress, and some way to cancel the copy.
>> And that can internally rely on ->direct_splice(), with appropriate
>> algorithms for determine the optimal chunk size.
>
> And perhaps we don't. Perhaps we can provide this much simpler
> data-plane interface that works well enough for most everyone and can
> avoid going down the async rat hole, yet again.

I think either buffering or async is needed to get good perforrmace
without too much complexity in the app (which is not good). Buffering
works quite well for regular I/O, so maybe its the way to go here as
well.

Thanks,
Miklos