From: Pavel Begunkov <asml.silence@gmail.com>
To: Mark Papadakis <markuspapadakis@icloud.com>, io-uring@vger.kernel.org
Subject: Re: Feature: zero-copy splice API/opcode
Date: Mon, 13 Jan 2020 00:21:04 +0300 [thread overview]
Message-ID: <457632cf-614c-ac55-b869-39b50a61e1fd@gmail.com> (raw)
In-Reply-To: <CBBC10BD-9497-4248-9E6A-AF2DE788E401@icloud.com>
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On 09/01/2020 17:58, Mark Papadakis wrote:
> Greetings,
>
> I ‘ve been trying to replicate the benefits provided by sendfile() using e.g O_DIRECT access, together with IOSQE_IO_LINK in SQE flags and MSG_ZEROCOPY, but it doesn’t appear to work. Other ideas didn’t work either.
>
> I would really appreciate a sendfile like SQE opcode, but maybe some sort of generic DMA/zero-copy based opcode based on splice semantics could be implemented, so that e.g a vmsplice() like alternative could also work.
>
Sounds interesting, I'll look into this. First, I want to dig a bit into
kernel's zero-copy and get an idea how to cover all use cases with a single
opcode, and that's probably keeping in mind p2p.
The obvious nuisance from perspective is that it needs 2 fds. Any other concerns?
>
> (That would be the last remaining bit of functionality missing from io_uring, now that Jens has implemented support for IOSQE_ASYNC, IORING_REGISTER_EVENTFD_ASYNC and for managing epoll FDs, for enabling support for io_uring on https://github.com/phaistos-networks/TANK ).
>
> Thank you,
> @markpapadakis
>
--
Pavel Begunkov
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prev parent reply other threads:[~2020-01-12 21:21 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-09 14:58 Feature: zero-copy splice API/opcode Mark Papadakis
2020-01-12 21:21 ` Pavel Begunkov [this message]
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