Messages in this thread | | | Date | Wed, 1 Nov 2006 17:30:43 +0100 | From | Pavel Machek <> | Subject | Re: [PATCH 1/2] Make x86_64 udelay() round up instead of down. |
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Hi!
> From: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> > > Port two patches from i386 to x86_64 delay.c to make sure all rounding is done > upward instead of downward. > > There is no sign in commit messages that the mismatch was done on purpose, and > "delay() guarantees sleeping at least for the specified time" is still a valid > rule IMHO.
> diff --git a/arch/x86_64/lib/delay.c b/arch/x86_64/lib/delay.c > index 50be909..7514df0 100644 > --- a/arch/x86_64/lib/delay.c > +++ b/arch/x86_64/lib/delay.c > @@ -40,13 +40,13 @@ EXPORT_SYMBOL(__delay); > > inline void __const_udelay(unsigned long xloops) > { > - __delay((xloops * HZ * cpu_data[raw_smp_processor_id()].loops_per_jiffy) >> 32); > + __delay((xloops * HZ * cpu_data[raw_smp_processor_id()].loops_per_jiffy) >> 32 + 1);
Well, if this should be *rounding* up, you should do
(xloops * HZ * cpu_data[raw_smp_processor_id()].loops_per_jiffy + 0xffffffff) >> 32
, no? Not sure if it matters...
Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html - 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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