linux-kernel - Re: [PATCH v2 0/8] optimise resheduling due to deferred tw

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Message-Id: <168126441455.57506.14487418062992045458.b4-ty@kernel.dk>
Date:   Tue, 11 Apr 2023 19:53:34 -0600
From:   Jens Axboe <axboe@...nel.dk>
To:     io-uring@...r.kernel.org, Pavel Begunkov <asml.silence@...il.com>
Cc:     linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 0/8] optimise resheduling due to deferred tw


On Thu, 06 Apr 2023 14:20:06 +0100, Pavel Begunkov wrote:
> io_uring extensively uses task_work, but when a task is waiting
> every new queued task_work batch will try to wake it up and so
> cause lots of scheduling activity. This series optimises it,
> specifically applied for rw completions and send-zc notifications
> for now, and will helpful for further optimisations.
> 
> Quick testing shows similar to v1 results, numbers from v1:
> For my zc net test once in a while waiting for a portion of buffers
> I've got 10x descrease in the number of context switches and 2x
> improvement in CPU util (17% vs 8%). In profiles, io_cqring_work()
> got down from 40-50% of CPU to ~13%.
> 
> [...]

Applied, thanks!

[1/8] io_uring: move pinning out of io_req_local_work_add
      commit: ab1c590f5c9b96d8d8843d351aed72469f8f2ef0
[2/8] io_uring: optimie local tw add ctx pinning
      commit: d73a572df24661851465c821d33c03e70e4b68e5
[3/8] io_uring: refactor __io_cq_unlock_post_flush()
      commit: c66ae3ec38f946edb1776d25c1c8cd63803b8ec3
[4/8] io_uring: add tw add flags
      commit: 8501fe70ae9855076ffb03a3670e02a7b3437304
[5/8] io_uring: inline llist_add()
      commit: 5150940079a3ce94d7474f6f5b0d6276569dc1de
[6/8] io_uring: reduce scheduling due to tw
      commit: 8751d15426a31baaf40f7570263c27c3e5d1dc44
[7/8] io_uring: refactor __io_cq_unlock_post_flush()
      commit: c66ae3ec38f946edb1776d25c1c8cd63803b8ec3
[8/8] io_uring: optimise io_req_local_work_add
      commit: 360cd42c4e95ff06d8d7b0a54e42236c7e7c187f

Best regards,
-- 
Jens Axboe