From: Patrick McHardy <kaber@trash.net>
To: David Lang <david.lang@digitalinsight.com>
Cc: netfilter@lists.netfilter.org
Subject: Re: even hash tables sizes, FAQ entry
Date: Sat, 21 Jul 2007 05:44:11 +0200 [thread overview]
Message-ID: <46A1810B.6030309@trash.net> (raw)
In-Reply-To: <Pine.LNX.4.63.0707201107480.24729@qynat.qvtvafvgr.pbz>
David Lang wrote:
> On Fri, 20 Jul 2007, Patrick McHardy wrote:
>>
>> None of this is :) hash_buckets can be changed at runtime through the
>> sysfs module parameter and the size can be chosen arbitary, in fact
>> the current -git tree will round it up to the next multiple of
>> PAGE_SIZE / (sizeof(struct hlist_head)) to avoid memory wastage.
>
>
> not knowing what that sizeof evaluates to
Its not something a user needs to know, but its 4 bytes on 32 bit and
8 bytes on 64 bit.
> has anyone checked to make
> sure that this doesn't cause pathalogical performance or distribution
> problems with this hash?
Yes. jhash has been extensively scrutinzed before becoming standard
for basically everything under net/. You can safely assume that all
hashsizes behave similar (and patches for outdates FAQs are welcome).
next prev parent reply other threads:[~2007-07-21 3:44 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-07-19 22:17 need advice for high traffic network Konstantin Svist
2007-07-19 22:17 ` David Lang
2007-07-19 22:40 ` Konstantin Svist
2007-07-19 22:59 ` Thomas Jacob
2007-07-19 23:17 ` Konstantin Svist
2007-07-19 23:28 ` Thomas Jacob
2007-07-19 23:35 ` Konstantin Svist
2007-07-19 23:44 ` Thomas Jacob
2007-07-20 0:18 ` Konstantin Svist
2007-07-20 7:48 ` Thomas Jacob
2007-07-20 17:51 ` David Lang
2007-07-20 23:14 ` Thomas Jacob
2007-07-19 23:47 ` even hash tables sizes, FAQ entry Thomas Jacob
2007-07-20 0:13 ` David Lang
2007-07-20 7:41 ` Thomas Jacob
2007-07-20 17:44 ` David Lang
2007-07-20 17:50 ` Patrick McHardy
2007-07-20 18:08 ` David Lang
2007-07-21 3:44 ` Patrick McHardy [this message]
2007-08-06 18:50 ` need advice for high traffic network R. DuFresne
2007-07-19 22:49 ` Thomas Jacob
2007-07-19 22:53 ` Konstantin Svist
2007-07-19 23:16 ` David Lang
2007-07-20 14:16 ` Gregory Carter
[not found] <200707202319.l6KNJMwx014487@mail3.jubileegroup.co.uk>
2007-07-21 6:41 ` even hash tables sizes, FAQ entry G.W. Haywood
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