Message-ID: <5f470c2e-eff9-41b0-ac7a-6cb6ddd5a89c@gmail.com>
Date:   Wed, 1 Dec 2021 20:42:43 +0000
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Subject: Re: [RFC 00/12] io_uring zerocopy send
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To:     David Ahern <dsahern@gmail.com>, io-uring@vger.kernel.org,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Cc:     Jakub Kicinski <kuba@kernel.org>,
        Jonathan Lemon <jonathan.lemon@gmail.com>,
        "David S . Miller" <davem@davemloft.net>,
        Willem de Bruijn <willemb@google.com>,
        Eric Dumazet <edumazet@google.com>,
        Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
        David Ahern <dsahern@kernel.org>, Jens Axboe <axboe@kernel.dk>
References: <cover.1638282789.git.asml.silence@gmail.com>
 <ae2d2dab-6f42-403a-f167-1ba3db3fd07f@gmail.com>
 <994e315b-fdb7-1467-553e-290d4434d853@gmail.com>
 <c4424a7a-2ef1-6524-9b10-1e7d1f1e1fe4@gmail.com>
From:   Pavel Begunkov <asml.silence@gmail.com>
In-Reply-To: <c4424a7a-2ef1-6524-9b10-1e7d1f1e1fe4@gmail.com>
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On 12/1/21 17:57, David Ahern wrote:
> On 12/1/21 8:32 AM, Pavel Begunkov wrote:
[...]
>>> mileage varies quite a bit.
>>
>> Interesting, any brief notes on the setup and the results? Dummy
> 
> VM on Chromebook. I just cloned your repos, built, install and test. As
> mentioned above, the skb_orphan_frags_rx change is missing from your
> repo and that is the key to your reported performance gains.

Just to clear misunderstandings if any, all the numbers in the
cover-letter were measured on the same kernel and during the same
boot, and it doesn't include the skb_orphan_frags_rx() change.
All double checked by looking at the traces.

When it's routed through the loopback paths (e.g. -D 127.0.0.1),
it's indeed slow for both msg_zerocopy and send-zc, and both
"benefit" in raw throughput from the hack.

-- 
Pavel Begunkov