Messages in this thread | | | Date | Sat, 12 Nov 2005 10:22:00 +0100 | From | Vojtech Pavlik <> | Subject | Re: [PATCH 13/39] NLKD/x86-64 - time adjustment |
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On Fri, Nov 11, 2005 at 03:12:15AM +0100, Andi Kleen wrote: > On Thursday 10 November 2005 15:23, Jan Beulich wrote: > > > > > >Please remove the ifdefs too. 64bit HPET support would be fine, but > > >only as a runtime mechanism, not compile time. > > > > This I added only for the purpose of not affecting existing code in > > existing configurations. If the code is generally acceptable, then I'll be > > more than happy to convert it. > > We can't use 64bit HPET everywhere because quite some chipsets only > support 32bit HPET. So it has to be a runtime switch depending on the > capabilities of the hardware.
Is there any advantage to using 64-bit HPET? It's read is even slower (and thus even more unusable in a vsyscall than a 32-bit HPET read), and the missing 32 bits can be quite easily added should we need them for computations, which I doubt.
> > >Can you remove debugger_jiffies please? > > >The code has to handle long delays anyways (e.g. if someone uses a target > > >probe), so we cannot rely on such hacks anyways. > > > > As above, I introduced this only to not affect existing code. If the added > > latency is no problem, then of course only the overflow safe code path > > should be kept, and then debugger_jiffies is completely unnecessary. > > Hmm - didn't notice anything particularly slow. Or what were you thinking > about regarding the latency? And it should only run at each timer interrupt, > so it isn't a fast path. So I guess it's best to run it always.
-- Vojtech Pavlik SuSE Labs, SuSE CR - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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