Date: Mon, 6 Dec 2010 14:10:34 -0500 From: Jung-uk Kim <jkim@FreeBSD.org> To: Andriy Gapon <avg@freebsd.org> Cc: freebsd-current@freebsd.org Subject: Re: non-invariant tsc and cputicker Message-ID: <201012061410.46351.jkim@FreeBSD.org> In-Reply-To: <4CFD31E0.8070107@freebsd.org> References: <4CF92852.20705@freebsd.org> <201012061334.22475.jkim@FreeBSD.org> <4CFD31E0.8070107@freebsd.org>
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On Monday 06 December 2010 01:56 pm, Andriy Gapon wrote: > 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. Yes, thanks to njl. He made it "somewhat bogus" from "totally bogus". I made it "almost correct" from "somewhat bogus" for modern P-state invariant CPUs. ;-) Jung-uk Kim
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