From: Rick Jones <rick.jones2@hpe.com>
To: Eric Dumazet <eric.dumazet@gmail.com>, Florian Westphal <fw@strlen.de>
Cc: David Miller <davem@davemloft.net>,
tom@herbertland.com, hannes@stressinduktion.org,
netdev@vger.kernel.org, kernel-team@fb.com, davewatson@fb.com,
alexei.starovoitov@gmail.com
Subject: Re: [PATCH net-next 0/6] kcm: Kernel Connection Multiplexor (KCM)
Date: Tue, 24 Nov 2015 10:09:34 -0800 [thread overview]
Message-ID: <5654A7DE.6030005@hpe.com> (raw)
In-Reply-To: <1448380194.22599.303.camel@edumazet-glaptop2.roam.corp.google.com>
On 11/24/2015 07:49 AM, Eric Dumazet wrote:
> But in the end, latencies were bigger, because the application had to
> copy from kernel to user (read()) the full message in one go. While if
> you wake up application for every incoming GRO message, we prefill cpu
> caches, and the last read() only has to copy the remaining part and
> benefit from hot caches (RFS up2date state, TCP socket structure, but
> also data in the application)
You can see something similar (at least in terms of latency) when
messing about with MTU sizes. For some message sizes - 8KB being a
popular one - you will see higher latency on the likes of netperf TCP_RR
with JumboFrames than you would with the standard 1500 byte MTU.
Something I saw on GbE links years back anyway. I chalked it up to
getting better parallelism between the NIC and the host.
Of course the service demands were lower with JumboFrames...
rick jones
next prev parent reply other threads:[~2015-11-24 18:09 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-20 21:21 [PATCH net-next 0/6] kcm: Kernel Connection Multiplexor (KCM) Tom Herbert
2015-11-20 21:21 ` [PATCH net-next 1/6] rcu: Add list_next_or_null_rcu Tom Herbert
2015-11-20 21:21 ` [PATCH net-next 2/6] net: Make sock_alloc exportable Tom Herbert
2015-11-20 21:21 ` [PATCH net-next 3/6] net: Add MSG_BATCH flag Tom Herbert
2015-11-23 10:02 ` Hannes Frederic Sowa
2015-11-20 21:21 ` [PATCH net-next 4/6] kcm: Kernel Connection Multiplexor module Tom Herbert
2015-11-20 22:50 ` Sowmini Varadhan
2015-11-20 23:19 ` Tom Herbert
2015-11-20 23:27 ` Sowmini Varadhan
2015-11-20 23:10 ` Alexei Starovoitov
2015-11-20 23:20 ` Tom Herbert
2015-11-23 9:42 ` Daniel Borkmann
2015-11-20 21:21 ` [PATCH net-next 5/6] kcm: Add statistics and proc interfaces Tom Herbert
2015-11-20 21:22 ` [PATCH net-next 6/6] kcm: Add description in Documentation Tom Herbert
2015-11-23 9:53 ` [PATCH net-next 0/6] kcm: Kernel Connection Multiplexor (KCM) Hannes Frederic Sowa
2015-11-23 12:43 ` Sowmini Varadhan
2015-11-23 17:33 ` Tom Herbert
2015-11-23 19:35 ` Hannes Frederic Sowa
2015-11-23 19:54 ` David Miller
2015-11-23 20:02 ` Tom Herbert
2015-11-24 11:25 ` Hannes Frederic Sowa
2015-11-24 15:49 ` David Miller
2015-11-24 15:27 ` Florian Westphal
2015-11-24 15:49 ` Eric Dumazet
2015-11-24 18:09 ` Rick Jones [this message]
2015-11-24 15:55 ` David Miller
2015-11-24 16:25 ` Florian Westphal
2015-11-24 17:00 ` Tom Herbert
2015-11-24 17:16 ` Florian Westphal
2015-11-24 17:43 ` Tom Herbert
2015-11-24 20:55 ` Florian Westphal
2015-11-24 21:49 ` Tom Herbert
2015-11-24 22:22 ` Florian Westphal
2015-11-24 22:25 ` David Miller
2015-11-24 22:45 ` Florian Westphal
2015-11-24 23:13 ` Hannes Frederic Sowa
2015-11-24 18:23 ` Hannes Frederic Sowa
2015-11-24 18:59 ` Alexei Starovoitov
2015-11-24 19:16 ` Hannes Frederic Sowa
2015-11-24 19:26 ` Hannes Frederic Sowa
2015-11-24 20:23 ` Alexei Starovoitov
[not found] ` <1448402288.1489559.449199721.64EBB346@webmail.messagingengine.com>
[not found] ` <20151124222109.GA86838@ast-mbp.thefacebook.com>
2015-11-25 10:38 ` Hannes Frederic Sowa
2015-11-25 16:26 ` Sowmini Varadhan
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