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From: Pavel Begunkov <[email protected]>
To: David Ahern <[email protected]>,
	[email protected], [email protected],
	[email protected]
Cc: "David S . Miller" <[email protected]>,
	Jakub Kicinski <[email protected]>,
	Jonathan Lemon <[email protected]>,
	Willem de Bruijn <[email protected]>,
	Jens Axboe <[email protected]>,
	[email protected]
Subject: Re: [PATCH net-next v4 00/27] io_uring zerocopy send
Date: Fri, 8 Jul 2022 15:26:13 +0100	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>

On 7/8/22 05:10, David Ahern wrote:
> On 7/7/22 5:49 AM, Pavel Begunkov wrote:
>> NOTE: Not be picked directly. After getting necessary acks, I'll be working
>>        out merging with Jakub and Jens.
>>
>> The patchset implements io_uring zerocopy send. It works with both registered
>> and normal buffers, mixing is allowed but not recommended. Apart from usual
>> request completions, just as with MSG_ZEROCOPY, io_uring separately notifies
>> the userspace when buffers are freed and can be reused (see API design below),
>> which is delivered into io_uring's Completion Queue. Those "buffer-free"
>> notifications are not necessarily per request, but the userspace has control
>> over it and should explicitly attaching a number of requests to a single
>> notification. The series also adds some internal optimisations when used with
>> registered buffers like removing page referencing.
>>
>>  From the kernel networking perspective there are two main changes. The first
>> one is passing ubuf_info into the network layer from io_uring (inside of an
>> in kernel struct msghdr). This allows extra optimisations, e.g. ubuf_info
>> caching on the io_uring side, but also helps to avoid cross-referencing
>> and synchronisation problems. The second part is an optional optimisation
>> removing page referencing for requests with registered buffers.
>>
>> Benchmarking with an optimised version of the selftest (see [1]), which sends
>> a bunch of requests, waits for completions and repeats. "+ flush" column posts
>> one additional "buffer-free" notification per request, and just "zc" doesn't
>> post buffer notifications at all.
>>
>> NIC (requests / second):
>> IO size | non-zc    | zc             | zc + flush
>> 4000    | 495134    | 606420 (+22%)  | 558971 (+12%)
>> 1500    | 551808    | 577116 (+4.5%) | 565803 (+2.5%)
>> 1000    | 584677    | 592088 (+1.2%) | 560885 (-4%)
>> 600     | 596292    | 598550 (+0.4%) | 555366 (-6.7%)
>>
>> dummy (requests / second):
>> IO size | non-zc    | zc             | zc + flush
>> 8000    | 1299916   | 2396600 (+84%) | 2224219 (+71%)
>> 4000    | 1869230   | 2344146 (+25%) | 2170069 (+16%)
>> 1200    | 2071617   | 2361960 (+14%) | 2203052 (+6%)
>> 600     | 2106794   | 2381527 (+13%) | 2195295 (+4%)
>>
>> Previously it also brought a massive performance speedup compared to the
>> msg_zerocopy tool (see [3]), which is probably not super interesting.
>>
> 
> can you add a comment that the above results are for UDP.

Oh, right, forgot to add it


> You dropped comments about TCP testing; any progress there? If not, can
> you relay any issues you are hitting?

Not really a problem, but for me it's bottle necked at NIC bandwidth
(~3GB/s) for both zc and non-zc and doesn't even nearly saturate a CPU.
Was actually benchmarked by my colleague quite a while ago, but can't
find numbers. Probably need to at least add localhost numbers or grab
a better server.

-- 
Pavel Begunkov

  reply	other threads:[~2022-07-08 14:28 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-07 11:49 [PATCH net-next v4 00/27] io_uring zerocopy send Pavel Begunkov
2022-07-07 11:49 ` [PATCH net-next v4 01/27] ipv4: avoid partial copy for zc Pavel Begunkov
2022-07-07 11:49 ` [PATCH net-next v4 02/27] ipv6: " Pavel Begunkov
2022-07-07 11:49 ` [PATCH net-next v4 03/27] skbuff: don't mix ubuf_info from different sources Pavel Begunkov
2022-07-07 11:49 ` [PATCH net-next v4 04/27] skbuff: add SKBFL_DONT_ORPHAN flag Pavel Begunkov
2022-07-07 11:49 ` [PATCH net-next v4 05/27] skbuff: carry external ubuf_info in msghdr Pavel Begunkov
2022-07-07 11:49 ` [PATCH net-next v4 06/27] net: Allow custom iter handler " Pavel Begunkov
2022-07-11 12:20   ` Pavel Begunkov
2022-07-07 11:49 ` [PATCH net-next v4 07/27] net: introduce managed frags infrastructure Pavel Begunkov
2022-07-07 11:49 ` [PATCH net-next v4 08/27] net: introduce __skb_fill_page_desc_noacc Pavel Begunkov
2022-07-07 11:49 ` [PATCH net-next v4 09/27] ipv4/udp: support externally provided ubufs Pavel Begunkov
2022-07-07 11:49 ` [PATCH net-next v4 10/27] ipv6/udp: " Pavel Begunkov
2022-07-07 11:49 ` [PATCH net-next v4 11/27] tcp: " Pavel Begunkov
2022-07-08  4:06   ` David Ahern
2022-07-08 14:03     ` Pavel Begunkov
2022-07-13 23:38       ` David Ahern
2022-07-07 11:49 ` [PATCH net-next v4 12/27] io_uring: initialise msghdr::msg_ubuf Pavel Begunkov
2022-07-07 11:49 ` [PATCH net-next v4 13/27] io_uring: export io_put_task() Pavel Begunkov
2022-07-07 11:49 ` [PATCH net-next v4 14/27] io_uring: add zc notification infrastructure Pavel Begunkov
2022-07-07 11:49 ` [PATCH net-next v4 15/27] io_uring: cache struct io_notif Pavel Begunkov
2022-07-07 11:49 ` [PATCH net-next v4 16/27] io_uring: complete notifiers in tw Pavel Begunkov
2022-07-07 11:49 ` [PATCH net-next v4 17/27] io_uring: add rsrc referencing for notifiers Pavel Begunkov
2022-07-07 11:49 ` [PATCH net-next v4 18/27] io_uring: add notification slot registration Pavel Begunkov
2022-07-07 11:49 ` [PATCH net-next v4 19/27] io_uring: wire send zc request type Pavel Begunkov
2022-07-07 11:49 ` [PATCH net-next v4 20/27] io_uring: account locked pages for non-fixed zc Pavel Begunkov
2022-07-07 11:49 ` [PATCH net-next v4 21/27] io_uring: allow to pass addr into sendzc Pavel Begunkov
2022-07-07 11:49 ` [PATCH net-next v4 22/27] io_uring: sendzc with fixed buffers Pavel Begunkov
2022-07-07 11:49 ` [PATCH net-next v4 23/27] io_uring: flush notifiers after sendzc Pavel Begunkov
2022-07-07 11:49 ` [PATCH net-next v4 24/27] io_uring: rename IORING_OP_FILES_UPDATE Pavel Begunkov
2022-07-07 11:49 ` [PATCH net-next v4 25/27] io_uring: add zc notification flush requests Pavel Begunkov
2022-07-07 11:49 ` [PATCH net-next v4 26/27] io_uring: enable managed frags with register buffers Pavel Begunkov
2022-07-07 11:49 ` [PATCH net-next v4 27/27] selftests/io_uring: test zerocopy send Pavel Begunkov
2022-07-08  4:10 ` [PATCH net-next v4 00/27] io_uring " David Ahern
2022-07-08 14:26   ` Pavel Begunkov [this message]
2022-07-11 12:56     ` Pavel Begunkov
2022-07-13 23:45       ` David Ahern
2022-07-14 18:55         ` Pavel Begunkov
2022-07-18  2:19           ` David Ahern
2022-07-20 13:32             ` Pavel Begunkov
2022-07-24 18:28             ` David Ahern
2022-07-27 10:51               ` Pavel Begunkov
2022-07-29 22:30                 ` David Ahern
2022-09-26 20:08               ` Pavel Begunkov
2022-09-28 19:31                 ` David Ahern
2022-09-28 20:11                   ` Pavel Begunkov

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