linux-kernel - Re: [PATCH 1/2] bitreversal program

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Message-ID: <4834533D.4030200@imap.cc>
Date:	Wed, 21 May 2008 18:52:13 +0200
From:	Tilman Schmidt <tilman@...p.cc>
To:	Soumyadip Das Mahapatra <kernelhacker@...ualserver.org>
CC:	Akinobu Mita <akinobu.mita@...il.com>,
	Harvey Harrison <harvey.harrison@...il.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] bitreversal program

Am 20.05.2008 17:25 schrieb Soumyadip Das Mahapatra:
> I know that my bitrev8() takes more instructions than that
> of yours. But we have to think about faster access of cpu cache over that
> of memory cache(which your bit_rev_table uses).

bitrev8() is used on every transferred byte for certain types of
ISDN connections, ie. with a steady rate of 8000 bytes/sec.
Depending on the driver, it will be called for individual data
bytes or possibly a small number of bytes at a time, typically
not more than 64, and typically in interrupt context.

I'd expect the table driven version to perform better in those
circumstances.

Thanks,
Tilman

-- 
Tilman Schmidt                    E-Mail: tilman@...p.cc
Bonn, Germany
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