From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>,
LKML <linux-kernel@vger.kernel.org>, Ingo Molnar <mingo@elte.hu>,
Greg KH <greg@kroah.com>
Subject: Re: [patch 1/2] infrastructure to debug (dynamic) objects
Date: Sat, 01 Mar 2008 23:42:57 +0100 [thread overview]
Message-ID: <1204411377.6240.13.camel@lappy> (raw)
In-Reply-To: <alpine.LFD.1.00.0803011215490.11084@apollo.tec.linutronix.de>
On Sat, 2008-03-01 at 12:44 +0100, Thomas Gleixner wrote:
> On Sat, 1 Mar 2008, Andrew Morton wrote:
> > > +
> > > +#define ODEBUG_HASH_SIZE 4096
> >
> > power-of-2 is said to be a very poor size for a hash table.
>
> The hash is not a randomized hash as one would expect. It's purely
> generated from the object address to simplify the lookup during the
> free check. So the power of 2 size is a good thing :) /me adds
> comment.
Power of two buckets work when used along with a golden ratio based hash
map - as done by linux/hash.h.
Power of two hash maps otoh suck royally.
next prev parent reply other threads:[~2008-03-01 22:43 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-03-01 10:24 [patch 0/2] object debugging infrastructure Thomas Gleixner
2008-03-01 10:24 ` [patch 1/2] infrastructure to debug (dynamic) objects Thomas Gleixner
2008-03-01 10:51 ` Andrew Morton
2008-03-01 11:44 ` Thomas Gleixner
2008-03-01 22:42 ` Peter Zijlstra [this message]
2008-03-02 10:06 ` Thomas Gleixner
2008-03-01 10:25 ` [patch 2/2] add timer specific object debugging code Thomas Gleixner
2008-03-02 5:20 ` [patch 0/2] object debugging infrastructure Greg KH
2008-03-02 9:54 ` Thomas Gleixner
2008-03-03 12:42 ` Andi Kleen
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