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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=5654A7DE.6030005@hpe.com \
--to=rick.jones2@hpe.com \
--cc=alexei.starovoitov@gmail.com \
--cc=davem@davemloft.net \
--cc=davewatson@fb.com \
--cc=eric.dumazet@gmail.com \
--cc=fw@strlen.de \
--cc=hannes@stressinduktion.org \
--cc=kernel-team@fb.com \
--cc=netdev@vger.kernel.org \
--cc=tom@herbertland.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.