Messages in this thread |  | | Subject | Re: [patch 4/9] Remove the TSC synchronization on SMP machines | From | Arjan van de Ven <> | Date | Tue, 13 Feb 2007 09:41:17 +0100 |
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On Tue, 2007-02-13 at 09:28 +0100, Andi Kleen wrote: > On Tuesday 13 February 2007 07:40, Arjan van de Ven wrote: > > On Mon, 2007-02-12 at 16:34 -0800, Christoph Lameter wrote: > > > On Fri, 2 Feb 2007, Andi Kleen wrote: > > > > > > > I've threatened to just disable RDTSC for ring 3 before, but it'll likely > > > > never happen because too many programs use it. > > > > > > Those programs are aware that they are fiddling around with low level > > > material but with this patchset we are going to have a non > > > monotonic time subsystem? > > > > no quite the opposite. gettimeofday() currently is NOT monotonic > > unfortunately. > > Anytime it is non monotonic that's a bug. We've had bugs > like this before, but recently we're doing reasonably well. Of course > there can be always improvements, but in general I don't agree > with your statement, sorry. You can usually rely on it being monotonic, > short of the known limitations (e.g. don't run ntpd)
oh I agree it should be monotonic, but I remember an argument I had with you several weeks ago where you were basically saying the opposite ;)
I'm happy to see gtod become more monotonic/reliable any way we can
-- if you want to mail me at work (you don't), use arjan (at) linux.intel.com Test the interaction between Linux and your BIOS via http://www.linuxfirmwarekit.org
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