From: David Miller <davem@davemloft.net>
To: dada1@cosmosbay.com
Cc: ak@suse.de, linux@horizon.com, akepner@sgi.com, netdev@vger.kernel.org
Subject: Re: [PATCH] NET : change layout of ehash table
Date: Fri, 09 Feb 2007 01:15:42 -0800 (PST) [thread overview]
Message-ID: <20070209.011542.21927454.davem@davemloft.net> (raw)
In-Reply-To: <200702091006.24242.dada1@cosmosbay.com>
From: Eric Dumazet <dada1@cosmosbay.com>
Date: Fri, 9 Feb 2007 10:06:24 +0100
> Yes, but a decent C compiler for such targets should not use a
> multiply instruction to perform a (idx * 12) operation... :)
Good point.
Actually, I could never get GCC to avoid a divide on sparc64 for
certain kinds of pointer arithmetic when the elements were not
a power of two. It probably has something to do with signedness.
I think I narrowed is down to the fact that you can't legally replace
a signed divide with shift/add/subtract. But I could be remembering
things wrong.
next prev parent reply other threads:[~2007-02-09 9:15 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-12-19 8:56 [PATCH] irlan: handle out of memory errors Akinobu Mita
2006-12-19 22:47 ` Samuel Ortiz
2007-02-07 8:12 ` David Miller
2007-02-07 10:59 ` [PATCH] NET : change layout of ehash table Eric Dumazet
2007-02-08 22:56 ` David Miller
2007-02-09 9:18 ` Andi Kleen
2007-02-09 8:40 ` David Miller
2007-02-09 8:57 ` Andi Kleen
2007-02-09 9:06 ` Eric Dumazet
2007-02-09 9:15 ` David Miller [this message]
2007-02-09 9:36 ` Eric Dumazet
2007-02-09 9:43 ` David Miller
2007-02-09 10:10 ` Andi Kleen
2007-02-09 17:44 ` [PATCH] NET : UDP can use sk_hash to speedup lookups Eric Dumazet
2007-02-09 23:45 ` David Miller
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