linux-kernel - Re: performance differences: "maxcpus=1" vs. "echo 0

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Message-ID: <20080325140825.GA19722@bit.office.eurotux.com>
Date:	Tue, 25 Mar 2008 14:08:25 +0000
From:	Luciano Rocha <luciano@...otux.com>
To:	Michael Meyer <mike65134@...oo.de>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: performance differences: "maxcpus=1" vs. "echo 0 >
	/sys/devices/system/cpu/cpu1/online"


On Tue, Mar 25, 2008 at 02:47:50PM +0100, Michael Meyer wrote:
> Hi, 
> 
> what is the difference between booting a dual core
> machine with "maxcpus=1" or by deactivating the second
> core at run time with "echo 0 >
> /sys/devices/system/cpu/cpu1/online"?

maxcpus=1 should turn off the SMP alternative and switch to UP only,
optimising some locks and instructions.

-- 
Luciano Rocha <luciano@...otux.com>
Eurotux Informática, S.A. <http://www.eurotux.com/>

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