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From: Jan Engelhardt <jengelh@linux01.gwdg.de>
To: dean gaudet <dean@arctic.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>,
	akpm@osdl.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] All Transmeta CPUs have constant TSCs
Date: Mon, 8 Jan 2007 21:19:24 +0100 (MET)	[thread overview]
Message-ID: <Pine.LNX.4.61.0701082118370.23737@yvahk01.tjqt.qr> (raw)
In-Reply-To: <Pine.LNX.4.64.0701072358010.26307@twinlark.arctic.org>


On Jan 8 2007 00:02, dean gaudet wrote:
>On Fri, 5 Jan 2007, Jan Engelhardt wrote:
>> On Jan 4 2007 17:48, H. Peter Anvin wrote:
>> >
>> >[i386] All Transmeta CPUs have constant TSCs
>> >All Transmeta CPUs ever produced have constant-rate TSCs.
>> 
>> A TSC is ticking according to the CPU frequency, is not it?
>
>transmeta decided years before intel and amd that a constant rate tsc 
>(unaffected by P-state) was the only sane choice.  on transmeta cpus the 
>tsc increments at the maximum cpu frequency no matter what the P-state 
>(and no matter what longrun is doing behind the kernel's back).
>
>mind you, many people thought this was a crazy choice at the time...
>
Well it defeats the purpose of TSC. I mean, they could have kept the "TSC" and
instead added a second TSC ticker, constant_tsc.


	-`J'
-- 

  reply	other threads:[~2007-01-08 20:22 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-01-05  1:48 H. Peter Anvin
2007-01-05 14:25 ` Jan Engelhardt
2007-01-08  8:02   ` dean gaudet
2007-01-08 20:19     ` Jan Engelhardt [this message]
2007-01-08 20:51       ` Chris Friesen
2007-01-08 20:51       ` H. Peter Anvin
2007-01-08 23:13         ` dean gaudet
2007-01-08 23:54           ` H. Peter Anvin

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