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Date:      Mon, 06 Dec 2010 20:56:32 +0200
From:      Andriy Gapon <avg@freebsd.org>
To:        Jung-uk Kim <jkim@freebsd.org>
Cc:        freebsd-current@freebsd.org
Subject:   Re: non-invariant tsc and cputicker
Message-ID:  <4CFD31E0.8070107@freebsd.org>
In-Reply-To: <201012061334.22475.jkim@FreeBSD.org>
References:  <4CF92852.20705@freebsd.org> <201012061243.08577.jkim@FreeBSD.org> <4CFD2441.5090408@freebsd.org> <201012061334.22475.jkim@FreeBSD.org>

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on 06/12/2010 20:34 Jung-uk Kim said the following:
> I understand that.  However, it is not clear to me why you want to 
> pessimize performance of old hardware.  If you can convince me old 
> hardware with slow timecounter hardware (e.g., i8254) does not hurt 
> too much, maybe it's okay.

Overlooked this point - TSC can be very well used as a timecounter.
And in that case non-invariant TSC would veto P-state changes, which is the proper
thing to do, IMO.

-- 
Andriy Gapon



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