From mboxrd@z Thu Jan  1 00:00:00 1970
From: "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH] git gc: Speed it up by 18% via faster hash comparisons
Date: Thu, 28 Apr 2011 13:23:52 -0700
Message-ID: <4DB9CCD8.6090701@zytor.com>
References: <20110427225114.GA16765@elte.hu>	<7voc3r5kzn.fsf@alter.siamese.dyndns.org>	<20110428062717.GA952@elte.hu>	<BANLkTik_2sHZ0OTgQeHpRnpmNsAmT=sAcA@mail.gmail.com>	<20110428093703.GB15349@elte.hu>	<BANLkTim+Kk_ah_4+pQKCi8bXtA8thRVRjQ@mail.gmail.com>	<4DB93D16.4000603@cs.helsinki.fi>	<BANLkTimD7KZz4fS0QynPui7-JQS10AkLtg@mail.gmail.com>	<4DB941CD.2050403@cs.helsinki.fi> <BANLkTikKUuBMDR2-OBYXw7jzs_+1wGacuA@mail.gmail.com>
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Cc: Pekka Enberg <penberg@cs.helsinki.fi>, kusmabite@gmail.com,
	Ingo Molnar <mingo@elte.hu>,
	Junio C Hamano <gitster@pobox.com>, git@vger.kernel.org,
	Thomas Gleixner <tglx@linutronix.de>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	Arnaldo Carvalho de Melo <acme@redhat.com>,
	=?ISO-8859-1?Q?Fr=E9d=E9ric_Weisbecker?= <fweisbec@gmail.com>
To: Tor Arntsen <tor@spacetec.no>
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On 04/28/2011 05:16 AM, Tor Arntsen wrote:
> On Thu, Apr 28, 2011 at 12:30, Pekka Enberg <penberg@cs.helsinki.fi> wrote:
>> Hi,
>>
>> On 4/28/11 1:19 PM, Erik Faye-Lund wrote:
> [alignment issues]
>>
>> Yes, ARM is a problem and I didn't try to claim otherwise. However, it's not
>> "impossible to fix" as you say with memalign().
> 
> MIPS (e.g. SGI machines) also bus-errors on non-aligned data.

On the other hand, MIPS has efficient instructions for accessing
known-unaligned data.

	-hpa