From: "H. Peter Anvin" <hpa@zytor.com>
To: linux-kernel@vger.kernel.org
Subject: Re: rdtsc to mili secs?
Date: 10 Nov 2000 13:38:16 -0800 [thread overview]
Message-ID: <8uhps8$1tm$1@cesium.transmeta.com> (raw)
In-Reply-To: <3A078C65.B3C146EC@mira.net> <E13t7ht-0007Kv-00@the-village.bc.nu> <20001110154254.A33@bug.ucw.cz>
Followup to: <20001110154254.A33@bug.ucw.cz>
By author: Pavel Machek <pavel@suse.cz>
In newsgroup: linux.dev.kernel
> >
> > Sensibly configured power saving/speed throttle systems do not change the
> > frequency at all. The duty cycle is changed and this controls the cpu
> > performance but the tsc is constant
>
> Do you have an example of notebook that does powersaving like that?
> I have 2 examples of notebooks with changing TSC speed...
>
Intel PIIX-based systems will do duty-cycle throttling, for example.
However, there are definitely notebooks that will mess with the
frequency. At Transmeta, we went through some considerable pain to
make sure RDTSC would count walltime even across Longrun transitions.
-hpa
--
<hpa@transmeta.com> at work, <hpa@zytor.com> in private!
"Unix gives you enough rope to shoot yourself in the foot."
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next prev parent reply other threads:[~2000-11-10 21:39 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2000-11-05 23:09 rdtsc to mili secs? Sushil Agarwal
2000-11-06 0:10 ` Andrea Arcangeli
2000-11-06 0:28 ` Alan Cox
2000-11-06 0:34 ` Andrea Arcangeli
2000-11-06 0:46 ` Alan Cox
2000-11-06 17:17 ` Anton Blanchard
2000-11-06 17:27 ` Alan Cox
2000-11-07 5:00 ` Antony Suter
2000-11-07 6:10 ` H. Peter Anvin
2000-11-07 12:18 ` Alan Cox
2000-11-10 14:42 ` Pavel Machek
2000-11-10 21:38 ` H. Peter Anvin [this message]
2000-11-10 22:23 ` Rogier Wolff
2000-11-10 23:00 ` H. Peter Anvin
2000-11-14 21:22 ` Pavel Machek
2000-11-15 21:05 ` H. Peter Anvin
2000-11-16 10:57 ` Vojtech Pavlik
2000-11-16 23:09 ` H. Peter Anvin
2000-11-18 20:13 ` Pavel Machek
2000-11-18 23:48 ` H. Peter Anvin
2000-11-19 9:21 ` Vojtech Pavlik
2000-11-18 20:12 ` Pavel Machek
2000-11-18 22:13 ` Vojtech Pavlik
2000-11-19 20:24 ` Pavel Machek
2000-11-19 21:46 ` Vojtech Pavlik
-- strict thread matches above, loose matches on Subject: below --
2000-11-06 8:15 ming_l
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