From: "Ilpo Järvinen" <ilpo.jarvinen@helsinki.fi>
To: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Cc: Kyle Moffett <kyle@moffetthome.net>,
LKML <linux-kernel@vger.kernel.org>,
Netdev <netdev@vger.kernel.org>,
netfilter-devel@vger.kernel.org,
Rusty Russell <rusty@rustcorp.com.au>
Subject: Re: [PATCH] Update jhash.h with the new version of Jenkins' hash
Date: Wed, 18 Feb 2009 13:50:43 +0200 (EET) [thread overview]
Message-ID: <Pine.LNX.4.64.0902181345010.31742@wrl-59.cs.helsinki.fi> (raw)
In-Reply-To: <alpine.DEB.2.00.0902171723330.27283@blackhole.kfki.hu>
On Tue, 17 Feb 2009, Jozsef Kadlecsik wrote:
> On Thu, 12 Feb 2009, Rusty Russell wrote:
>
> > My concern was that it's also bigger (and we inline it). Performance is
> > pretty much a wash since we so rarely hash more than a few words.
>
> In netfilter/conntrack (;-) we call the hash function for every packet, so
> even if a small number of cycle can be gained at one lookup, I think it's
> worth. And in the IPv4/IPv6 neutral nf_conntrack we hash 9 words.
FYI, I once looked into inlining cost and jhash functions were among the
most wasteful (kernel-wide). Multiple jhash bodies were 100+ bytes, and
the overall cost was 10k+. I never got to the final submit of the
uninlining patch though...
--
i.
next prev parent reply other threads:[~2009-02-18 11:50 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-02-11 10:19 [PATCH] Update jhash.h with the new version of Jenkins' hash Jozsef Kadlecsik
2009-02-11 20:19 ` Michał Mirosław
2009-02-11 22:50 ` Jozsef Kadlecsik
2009-02-11 23:23 ` Michał Mirosław
2009-02-12 0:12 ` wli
2009-02-12 0:29 ` David Miller
2009-02-12 0:41 ` Jan Engelhardt
2009-02-12 9:05 ` Jarek Poplawski
2009-02-12 9:55 ` Jarek Poplawski
2009-02-12 9:11 ` Jozsef Kadlecsik
2009-02-12 9:16 ` Patrick McHardy
2009-02-12 9:41 ` Jozsef Kadlecsik
2009-02-12 13:46 ` Kyle Moffett
2009-02-17 17:13 ` Jozsef Kadlecsik
2009-02-18 5:11 ` Rusty Russell
2009-02-18 11:50 ` Ilpo Järvinen [this message]
2009-02-12 19:58 ` Eric W. Biederman
2009-02-12 2:58 ` Rusty Russell
-- strict thread matches above, loose matches on Subject: below --
2009-02-10 19:40 Jozsef Kadlecsik
2009-02-10 21:19 ` Scott Feldman
2009-02-10 22:03 ` Jozsef Kadlecsik
2009-02-11 1:17 ` David Miller
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=Pine.LNX.4.64.0902181345010.31742@wrl-59.cs.helsinki.fi \
--to=ilpo.jarvinen@helsinki.fi \
--cc=kadlec@blackhole.kfki.hu \
--cc=kyle@moffetthome.net \
--cc=linux-kernel@vger.kernel.org \
--cc=netdev@vger.kernel.org \
--cc=netfilter-devel@vger.kernel.org \
--cc=rusty@rustcorp.com.au \
/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).