linux-kernel - Re: scheduler vs hardware? (was Re: another i7 (linux) bug?)

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Message-ID: <4B59CB32.5080901@nortel.com>
Date:	Fri, 22 Jan 2010 09:58:42 -0600
From:	"Chris Friesen" <cfriesen@...tel.com>
To:	Luca Zini <luca.zini@...il.com>
CC:	Mike Galbraith <efault@....de>,
	Peter Zijlstra <peterz@...radead.org>, aagaande@...il.com,
	rdelcueto@...mail.com, mingo@...e.hu,
	linux-kernel <linux-kernel@...r.kernel.org>,
	Alex Chiang <achiang@...com>
Subject: Re: scheduler vs hardware? (was Re: another i7  (linux) bug?)


On 01/22/2010 05:22 AM, Luca Zini wrote:

> with nice set to 19 a processor 3 reach the maximum speed,  with nice
set to
> -20 its maximum value is 300-400 mhz under the maximum value.

I wonder if at lower nice levels the timing on something changes,
forcing multiple cores to be active just often enough to keep the i7
from doing the turbo boost thing, whereas with higher nice levels
everything is serialized allowing the boost to be enabled.

Chris
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