From: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
To: linux-kernel@vger.kernel.org
Cc: netdev@vger.kernel.org, netfilter-devel@vger.kernel.org,
Linus Torvalds <torvalds@osdl.org>,
Rusty Russell <rusty@rustcorp.com.au>,
Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Subject: [PATCH 0/2] New jhash function
Date: Thu, 25 Nov 2010 14:15:06 +0100 [thread overview]
Message-ID: <1290690908-794-1-git-send-email-kadlec@blackhole.kfki.hu> (raw)
Hi,
Please consider applying the following patch:
The current jhash.h implements the lookup2() hash function by Bob Jenkins.
However, lookup2() is outdated as Bob wrote a new hash function called
lookup3(). The new hash function
- mixes better than lookup2(): it passes the check that every input bit
changes every output bit 50% of the time, while lookup2() failed it.
- performs better: compiled with -O2 on Core2 Duo, lookup3() 20-40% faster
than lookup2() depending on the key length.
You can read a longer comparison of the two and other hash functions at
http://burtleburtle.net/bob/hash/doobs.html.
jhash is widely used in the kernel and because the functions
are inlined, the cost in size is significant. The new functions
are slightly larger than the previous ones so the new implementation
uses non-inlined fucntions. (See
http://lkml.indiana.edu/hypermail//linux/kernel/0902.2/01149.html).
Therefore the first patch replaces the calls to the internal macros
of jhash with the jhash function calls and the second patch contains
the implementation of the new jhash functions.
Jozsef Kadlecsik (2):
Prepare the tree for un-inlined jhash.
The new jhash implementation
include/linux/jhash.h | 136 ++-------------------------------
lib/Makefile | 2 +-
lib/jhash.c | 153 ++++++++++++++++++++++++++++++++++++++
net/ipv6/inet6_connection_sock.c | 18 ++---
net/ipv6/reassembly.c | 36 ++++-----
5 files changed, 186 insertions(+), 159 deletions(-)
create mode 100644 lib/jhash.c
next reply other threads:[~2010-11-25 13:15 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-25 13:15 Jozsef Kadlecsik [this message]
2010-11-25 13:15 ` [PATCH 1/2] Prepare the tree for un-inlined jhash Jozsef Kadlecsik
2010-11-25 13:15 ` [PATCH 2/2] The new jhash implementation Jozsef Kadlecsik
2010-11-25 13:49 ` Eric Dumazet
2010-11-25 13:55 ` Changli Gao
2010-11-25 14:05 ` Eric Dumazet
2010-11-25 14:41 ` Jozsef Kadlecsik
2010-11-25 17:21 ` Eric Dumazet
2010-11-25 21:14 ` Jozsef Kadlecsik
2010-11-27 3:31 ` Rusty Russell
2010-12-03 12:38 ` [PATCH 0/2] New jhash function Jozsef Kadlecsik
2010-12-03 12:39 ` [PATCH 1/2] Remove calls to jhash internals Jozsef Kadlecsik
2010-12-03 12:39 ` [PATCH 2/2] The new jhash implementation Jozsef Kadlecsik
2010-12-08 17:09 ` [PATCH 0/2] New jhash function David Miller
2010-12-08 21:23 ` Rusty Russell
2010-12-10 4:19 ` David Miller
2010-11-25 13:39 ` [PATCH 1/2] Prepare the tree for un-inlined jhash Jan Engelhardt
2010-11-25 13:57 ` Jozsef Kadlecsik
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