From: Pavel Begunkov <[email protected]>
To: Hao Xu <[email protected]>, Jens Axboe <[email protected]>
Cc: [email protected], Joseph Qi <[email protected]>
Subject: Re: [PATCH v5 0/6] task work optimization
Date: Wed, 24 Nov 2021 21:41:10 +0000 [thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
On 11/24/21 12:21, Hao Xu wrote:
> v4->v5
> - change the implementation of merge_wq_list
They only concern I had was about 6/6 not using inline completion
infra, when it's faster to grab ->uring_lock. i.e.
io_submit_flush_completions(), which should be faster when batching
is good.
Looking again through the code, the only user is SQPOLL
io_req_task_work_add(req, !!(req->ctx->flags & IORING_SETUP_SQPOLL));
And with SQPOLL the lock is mostly grabbed by the SQPOLL task only,
IOW for pure block rw there shouldn't be any contention.
Doesn't make much sense, what am I missing?
How many requests are completed on average per tctx_task_work()?
It doesn't apply to for-5.17/io_uring, here is a rebase:
https://github.com/isilence/linux.git haoxu_tw_opt
link: https://github.com/isilence/linux/tree/haoxu_tw_opt
With that first 5 patches look good, so for them:
Reviewed-by: Pavel Begunkov <[email protected]>
but I still don't understand how 6/6 is better. Can it be because of
indirect branching? E.g. would something like this give the result?
- req->io_task_work.func(req, locked);
+ INDIRECT_CALL_1(req->io_task_work.func, io_req_task_complete, req, locked);
> Hao Xu (6):
> io-wq: add helper to merge two wq_lists
> io_uring: add a priority tw list for irq completion work
> io_uring: add helper for task work execution code
> io_uring: split io_req_complete_post() and add a helper
> io_uring: move up io_put_kbuf() and io_put_rw_kbuf()
> io_uring: batch completion in prior_task_list
>
> fs/io-wq.h | 22 +++++++
> fs/io_uring.c | 158 +++++++++++++++++++++++++++++++++-----------------
> 2 files changed, 128 insertions(+), 52 deletions(-)
>
--
Pavel Begunkov
next prev parent reply other threads:[~2021-11-24 21:41 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-24 12:21 [PATCH v5 0/6] task work optimization Hao Xu
2021-11-24 12:21 ` [PATCH 1/6] io-wq: add helper to merge two wq_lists Hao Xu
2021-11-24 12:21 ` [PATCH 2/6] io_uring: add a priority tw list for irq completion work Hao Xu
2021-11-24 12:21 ` [PATCH 3/6] io_uring: add helper for task work execution code Hao Xu
2021-11-24 12:22 ` [PATCH 4/6] io_uring: split io_req_complete_post() and add a helper Hao Xu
2021-11-24 12:22 ` [PATCH 5/6] io_uring: move up io_put_kbuf() and io_put_rw_kbuf() Hao Xu
2021-11-24 12:22 ` [PATCH 6/6] io_uring: batch completion in prior_task_list Hao Xu
2021-11-24 21:41 ` Pavel Begunkov [this message]
2021-11-25 11:37 ` [PATCH v5 0/6] task work optimization Hao Xu
2021-11-25 15:27 ` Pavel Begunkov
2021-11-26 3:58 ` Hao Xu
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