From: David Miller <davem@davemloft.net>
To: eric.dumazet@gmail.com
Cc: netdev@vger.kernel.org
Subject: Re: [PATCH net-next] net: output path optimizations
Date: Tue, 07 Aug 2012 16:26:30 -0700 (PDT) [thread overview]
Message-ID: <20120807.162630.311474956563871276.davem@davemloft.net> (raw)
In-Reply-To: <1344341996.28967.87.camel@edumazet-glaptop>
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Tue, 07 Aug 2012 14:19:56 +0200
> From: Eric Dumazet <edumazet@google.com>
>
> 1) Avoid dirtying neighbour's confirmed field.
>
> TCP workloads hits this cache line for each incoming ACK.
> Lets write n->confirmed only if there is a jiffie change.
>
> 2) Optimize neigh_hh_output() for the common Ethernet case, were
> hh_len is less than 16 bytes. Replace the memcpy() call
> by two inlined 64bit load/stores on x86_64.
>
> Bench results using udpflood test, with -C option (MSG_CONFIRM flag
> added to sendto(), to reproduce the n->confirmed dirtying on UDP)
>
> 24 threads doing 1.000.000 UDP sendto() on dummy device, 4 runs.
>
> before : 2.247s, 2.235s, 2.247s, 2.318s
> after : 1.884s, 1.905s, 1.891s, 1.895s
>
> Signed-off-by: Eric Dumazet <edumazet@google.com>
Applied, I'd like to significantly redo how the neigh confirmation
stuff works.
I'm not at all surprised it shows up on TCP workloads.
prev parent reply other threads:[~2012-08-07 23:26 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-07 12:19 [PATCH net-next] net: output path optimizations Eric Dumazet
2012-08-07 23:26 ` David Miller [this message]
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=20120807.162630.311474956563871276.davem@davemloft.net \
--to=davem@davemloft.net \
--cc=eric.dumazet@gmail.com \
--cc=netdev@vger.kernel.org \
/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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).