From: Jens Axboe <axboe@kernel.dk>
To: io-uring@vger.kernel.org
Cc: xuanzhuo@linux.alibaba.com, Dust.li@linux.alibaba.com
Subject: [PATCHSET 0/5] Allow batching of inline completions
Date: Tue, 23 Jun 2020 09:16:24 -0600 [thread overview]
Message-ID: <20200623151629.17197-1-axboe@kernel.dk> (raw)
As Xuan Zhuo <xuanzhuo@linux.alibaba.com> reported here:
https://lore.kernel.org/io-uring/34ecb5c9-5822-827f-6e7b-973bea543569@kernel.dk/T/#me32d6897f976e8268284ff5cbdb3696010c2b7ba
we can do a bit better when dealing with inline completions from the
submission path. This patchset cleans up the standard completion
logic, then builds on top of that to allow collecting completions done
at submission time. This allows io_uring to amortize the cost of needing
to grab the completion lock, and updating the CQ ring as well.
On a silly t/io_uring NOP test on my laptop, this brings about a 20%
increase in performance. Xuan Zhuo reports that it changes his SQPOLL
based UDP processing (running at 800K PPS) profile from:
17.97% [kernel] [k] copy_user_generic_unrolled
13.92% [kernel] [k] io_commit_cqring
11.04% [kernel] [k] __io_cqring_fill_event
10.33% [kernel] [k] udp_recvmsg
5.94% [kernel] [k] skb_release_data
4.31% [kernel] [k] udp_rmem_release
2.68% [kernel] [k] __check_object_size
2.24% [kernel] [k] __slab_free
2.22% [kernel] [k] _raw_spin_lock_bh
2.21% [kernel] [k] kmem_cache_free
2.13% [kernel] [k] free_pcppages_bulk
1.83% [kernel] [k] io_submit_sqes
1.38% [kernel] [k] page_frag_free
1.31% [kernel] [k] inet_recvmsg
to
19.99% [kernel] [k] copy_user_generic_unrolled
11.63% [kernel] [k] skb_release_data
9.36% [kernel] [k] udp_rmem_release
8.64% [kernel] [k] udp_recvmsg
6.21% [kernel] [k] __slab_free
4.39% [kernel] [k] __check_object_size
3.64% [kernel] [k] free_pcppages_bulk
2.41% [kernel] [k] kmem_cache_free
2.00% [kernel] [k] io_submit_sqes
1.95% [kernel] [k] page_frag_free
1.54% [kernel] [k] io_put_req
[...]
0.07% [kernel] [k] io_commit_cqring
0.44% [kernel] [k] __io_cqring_fill_event
which looks much nicer.
Patches are against my for-5.9/io_uring branch.
--
Jens Axboe
next reply other threads:[~2020-06-23 15:16 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-23 15:16 Jens Axboe [this message]
2020-06-23 15:16 ` [PATCH 1/5] io_uring: provide generic io_req_complete() helper Jens Axboe
2020-06-23 15:16 ` [PATCH 2/5] io_uring: add 'io_comp_state' to struct io_submit_state Jens Axboe
2020-06-23 15:16 ` [PATCH 3/5] io_uring: pass down completion state on the issue side Jens Axboe
2020-06-23 15:16 ` [PATCH 4/5] io_uring: pass in completion state to appropriate issue side handlers Jens Axboe
2020-06-23 15:16 ` [PATCH 5/5] io_uring: enable READ/WRITE to use deferred completions Jens Axboe
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