Re: [PATCHSET v2 0/6] io_uring: add support for open/close

Jens Axboe
2020-01-17T00:51:43Z

On 1/16/20 5:44 PM, Colin Walters wrote:
>
>
> On Thu, Jan 16, 2020, at 5:50 PM, Stefan Metzmacher wrote:
>>
>> The client can compound a chain with open, getinfo, read, close
>> getinfo, read and close get an file handle of -1 and implicitly
>> get the fd generated/used in the previous request.
>
> Sounds similar to https://capnproto.org/rpc.html too.

Never heard of it, but I don't see how you can do any of this in an
efficient manner without kernel support. Unless it's just wrapping the
communication in its own protocol and using that as the basis for the
on-wire part. It has "infinitely faster" in a yellow sticker, so it must
work :-)

> But that seems most valuable in a situation with nontrivial latency.

Which is basically what Stefan is looking at, over the network open,
read, close etc is pretty nondeterministic. But even for local storage,
being able to setup a bundle like that and have it automagically work
makes for easier programming and more efficient communication with the
kernel.

--
Jens Axboe