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From: Hannes Reinecke <hare@suse.de>
To: Jens Axboe <axboe@kernel.dk>,
	linux-aio@kvack.org, linux-block@vger.kernel.org,
	linux-api@vger.kernel.org
Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com,
	jannh@google.com, viro@ZenIV.linux.org.uk
Subject: Re: [PATCH 18/19] io_uring: allow workqueue item to handle multiple buffered requests
Date: Sun, 10 Feb 2019 10:31:53 +0100	[thread overview]
Message-ID: <476b621e-85e2-35df-c1e3-50395ca4ebeb@suse.de> (raw)
In-Reply-To: <20190209211346.26060-19-axboe@kernel.dk>

On 2/9/19 10:13 PM, Jens Axboe wrote:
> Right now we punt any buffered request that ends up triggering an
> -EAGAIN to an async workqueue. This works fine in terms of providing
> async execution of them, but it also can create quite a lot of work
> queue items. For sequentially buffered IO, it's advantageous to
> serialize the issue of them. For reads, the first one will trigger a
> read-ahead, and subsequent request merely end up waiting on later pages
> to complete. For writes, devices usually respond better to streamed
> sequential writes.
> 
> Add state to track the last buffered request we punted to a work queue,
> and if the next one is sequential to the previous, attempt to get the
> previous work item to handle it. We limit the number of sequential
> add-ons to the a multiple (8) of the max read-ahead size of the file.
> This should be a good number for both reads and wries, as it defines the
> max IO size the device can do directly.
> 
> This drastically cuts down on the number of context switches we need to
> handle buffered sequential IO, and a basic test case of copying a big
> file with io_uring sees a 5x speedup.
> 
> Signed-off-by: Jens Axboe <axboe@kernel.dk>
> ---
>   fs/io_uring.c | 269 ++++++++++++++++++++++++++++++++++++++++----------
>   1 file changed, 218 insertions(+), 51 deletions(-)
> 
Reviewed-by: Hannes Reinecke <hare@suse.com>

Cheers,

Hannes


  reply	other threads:[~2019-02-10  9:32 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-09 21:13 [PATCHSET v14] io_uring IO interface Jens Axboe
2019-02-09 21:13 ` [PATCH 01/19] fs: add an iopoll method to struct file_operations Jens Axboe
2019-02-09 21:13 ` [PATCH 02/19] block: wire up block device iopoll method Jens Axboe
2019-02-09 21:13 ` [PATCH 03/19] block: add bio_set_polled() helper Jens Axboe
2019-02-09 21:13 ` [PATCH 04/19] iomap: wire up the iopoll method Jens Axboe
2019-02-09 21:13 ` [PATCH 05/19] Add io_uring IO interface Jens Axboe
2019-02-10 12:03   ` Thomas Gleixner
2019-02-10 14:19     ` Jens Axboe
2019-02-09 21:13 ` [PATCH 06/19] io_uring: add fsync support Jens Axboe
2019-02-09 21:13 ` [PATCH 07/19] io_uring: support for IO polling Jens Axboe
2019-02-09 21:13 ` [PATCH 08/19] fs: add fget_many() and fput_many() Jens Axboe
2019-02-09 21:13 ` [PATCH 09/19] io_uring: use fget/fput_many() for file references Jens Axboe
2019-02-09 21:13 ` [PATCH 10/19] io_uring: batch io_kiocb allocation Jens Axboe
2019-02-09 21:13 ` [PATCH 11/19] block: implement bio helper to add iter bvec pages to bio Jens Axboe
2019-02-09 21:13 ` [PATCH 12/19] io_uring: add support for pre-mapped user IO buffers Jens Axboe
2019-02-09 21:13 ` [PATCH 13/19] net: split out functions related to registering inflight socket files Jens Axboe
2019-02-09 21:13 ` [PATCH 14/19] io_uring: add file set registration Jens Axboe
2019-02-09 23:52   ` Matt Mullins
2019-02-10  0:47     ` Jens Axboe
     [not found]       ` <60e4c6a489549daad1fb2c5e8eee5496c668d79a.camel@fb.com>
2019-02-10  2:34         ` Jens Axboe
2019-02-10  2:57           ` Jens Axboe
2019-02-10 19:55             ` Matt Mullins
2019-02-09 21:13 ` [PATCH 15/19] io_uring: add submission polling Jens Axboe
2019-02-09 21:13 ` [PATCH 16/19] io_uring: add io_kiocb ref count Jens Axboe
2019-02-10  9:19   ` Hannes Reinecke
2019-02-09 21:13 ` [PATCH 17/19] io_uring: add support for IORING_OP_POLL Jens Axboe
2019-02-10  9:28   ` Hannes Reinecke
2019-02-09 21:13 ` [PATCH 18/19] io_uring: allow workqueue item to handle multiple buffered requests Jens Axboe
2019-02-10  9:31   ` Hannes Reinecke [this message]
2019-02-09 21:13 ` [PATCH 19/19] io_uring: add io_uring_event cache hit information Jens Axboe
2019-02-10  9:36   ` Hannes Reinecke
2019-02-10 13:39     ` Jens Axboe
  -- strict thread matches above, loose matches on Subject: below --
2019-02-11 19:00 [PATCHSET v15] io_uring IO interface Jens Axboe
2019-02-11 19:00 ` [PATCH 18/19] io_uring: allow workqueue item to handle multiple buffered requests Jens Axboe
2019-02-08 17:34 [PATCHSET v13] io_uring IO interface Jens Axboe
2019-02-08 17:34 ` [PATCH 18/19] io_uring: allow workqueue item to handle multiple buffered requests Jens Axboe

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