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From: Ming Lei <[email protected]>
To: Jens Axboe <[email protected]>,
	[email protected], [email protected]
Cc: [email protected],
	Miklos Szeredi <[email protected]>,
	ZiyangZhang <[email protected]>,
	Xiaoguang Wang <[email protected]>,
	Bernd Schubert <[email protected]>,
	Pavel Begunkov <[email protected]>,
	Stefan Hajnoczi <[email protected]>,
	Dan Williams <[email protected]>,
	[email protected]
Subject: Re: [PATCH V6 03/17] io_uring: add generic IORING_OP_FUSED_CMD
Date: Sat, 1 Apr 2023 22:35:47 +0800	[thread overview]
Message-ID: <ZChBQ3EJ/[email protected]> (raw)
In-Reply-To: <[email protected]>

On Thu, Mar 30, 2023 at 07:36:16PM +0800, Ming Lei wrote:
> Multiple requests submitted as one whole request logically, and the 1st one
> is primary command(IORING_OP_FUSED_CMD), and the others are secondary
> requests, which number can be retrieved from primary SQE.
> 
> Primary command is responsible for providing resources and submitting
> secondary requests, which depends on primary command's resources, and
> primary command won't be completed until all secondary requests are done.
> 
> The provided resource has same lifetime with primary command, and it
> lifetime won't cross multiple OPs, and this way provides safe way for
> secondary OPs to use the resource.
> 
> Add generic IORING_OP_FUSED_CMD for modeling this primary/secondary
> relationship among requests.

BTW, this model also solves 1:N dependency problem of io_uring.

Current io_uring can't handle this kind of dependency(1:N) efficiently,
and simply convert it into one linked list:

- N requests(1~n) depends on one request(0), and there isn't dependency among
these N requests

- current io_uring converts the dependency to linked list of (N + 1) requests
(0, 1, ...., n), in which all requests are just issued one by one from 0 to n,
inefficiently

The primary/secondary model solves it by issuing request 0 first, then issues
all other N requests concurrently.


Thanks,
Ming


  reply	other threads:[~2023-04-01 14:36 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-30 11:36 [PATCH V6 00/17] io_uring/ublk: add generic IORING_OP_FUSED_CMD Ming Lei
2023-03-30 11:36 ` [PATCH V6 01/17] io_uring: increase io_kiocb->flags into 64bit Ming Lei
2023-03-30 11:36 ` [PATCH V6 02/17] io_uring: use ctx->cached_sq_head to calculate left sqes Ming Lei
2023-03-30 11:36 ` [PATCH V6 03/17] io_uring: add generic IORING_OP_FUSED_CMD Ming Lei
2023-04-01 14:35   ` Ming Lei [this message]
2023-03-30 11:36 ` [PATCH V6 04/17] io_uring: support providing buffer by IORING_OP_FUSED_CMD Ming Lei
2023-03-30 11:36 ` [PATCH V6 05/17] io_uring: support OP_READ/OP_WRITE for fused secondary request Ming Lei
2023-03-30 11:36 ` [PATCH V6 06/17] io_uring: support OP_SEND_ZC/OP_RECV " Ming Lei
2023-03-30 11:36 ` [PATCH V6 07/17] block: ublk_drv: add common exit handling Ming Lei
2023-03-30 11:36 ` [PATCH V6 08/17] block: ublk_drv: don't consider flush request in map/unmap io Ming Lei
2023-03-30 11:36 ` [PATCH V6 09/17] block: ublk_drv: add two helpers to clean up map/unmap request Ming Lei
2023-03-30 11:36 ` [PATCH V6 10/17] block: ublk_drv: clean up several helpers Ming Lei
2023-03-30 11:36 ` [PATCH V6 11/17] block: ublk_drv: cleanup 'struct ublk_map_data' Ming Lei
2023-03-30 11:36 ` [PATCH V6 12/17] block: ublk_drv: cleanup ublk_copy_user_pages Ming Lei
2023-03-31 16:22   ` Bernd Schubert
2023-03-30 11:36 ` [PATCH V6 13/17] block: ublk_drv: grab request reference when the request is handled by userspace Ming Lei
2023-03-30 11:36 ` [PATCH V6 14/17] block: ublk_drv: support to copy any part of request pages Ming Lei
2023-03-30 11:36 ` [PATCH V6 15/17] block: ublk_drv: add read()/write() support for ublk char device Ming Lei
2023-03-30 11:36 ` [PATCH V6 16/17] block: ublk_drv: don't check buffer in case of zero copy Ming Lei
2023-03-30 11:36 ` [PATCH V6 17/17] block: ublk_drv: apply io_uring FUSED_CMD for supporting " Ming Lei
2023-03-31 19:13   ` Bernd Schubert
2023-04-01 13:19     ` Ming Lei
2023-03-31 19:55   ` Bernd Schubert
2023-04-01 13:22     ` Ming Lei
2023-04-03  9:25     ` Bernd Schubert
2023-04-03  1:11 ` [PATCH V6 00/17] io_uring/ublk: add generic IORING_OP_FUSED_CMD Ming Lei
2023-04-03  1:24   ` Jens Axboe
2023-04-04  7:48     ` Ming Lei
2023-04-03  1:23 ` (subset) " Jens Axboe
2023-04-18 19:38 ` Bernd Schubert
2023-04-19  1:51   ` Ming Lei
2023-04-19  9:56     ` Bernd Schubert
2023-04-19 11:19       ` Ming Lei
2023-04-19 15:42         ` Bernd Schubert
2023-04-20  1:18           ` Pavel Begunkov
2023-04-20  1:38           ` Ming Lei
2023-04-21 22:38             ` Bernd Schubert

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