Date: Mon, 6 Dec 2010 14:27:36 -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: <201012061429.08085.jkim@FreeBSD.org> In-Reply-To: <4CFD34E1.40008@freebsd.org> References: <4CF92852.20705@freebsd.org> <201012061401.17904.jkim@FreeBSD.org> <4CFD34E1.40008@freebsd.org>
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On Monday 06 December 2010 02:09 pm, Andriy Gapon wrote: > on 06/12/2010 21:01 Jung-uk Kim said the following: > > :-) Don't get me wrong, I generally agree with you *iff* it does > > : not > > > > hurt too much. Anyway, this issue should be resolved from the > > root, i.e., kern_resouce.c, if possible. > > But what to resolve there? Better algorithm for stat. > I just want to always have a stable source "cpu ticks", and then > everything else should just work? If we had one, yes. But we don't, at least for old x86 hardware. :-( > BTW, if someone comes up with a patch for more or less correct > accounting when "cpu ticks" frequency is allowed to change, then I > am all for it. But, IMO, it's just easier to use stable "cpu > ticks". If it doesn't hurt too much, yes. Remember the P-state invariant CPUs are pretty new. SMP-correct TSC is quite rare if there is any. Jung-uk Kim
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