kernel-ark/arch
Ross Biro 79c62cf178 [PATCH] x86_64: Make udelay more accurate
The attempt to avoid overflow in __delay caused varying precision
on different CPUs depending on differences in the CPU speed.

We should be able to do this multiplication with out overflowing
provided the
cpu is running at less than about 128 GHz.  xloops < 20000 * 0x10c6.
loops_per_jiffy * HZ <= cpu_clock_speed.  So if the cpu clock speed
< 2^64/(20000 * 0x10c6) = 2^64/ 51E6CC0 < 2^64/2^27 = 2^37 = 128G we
will not overflow the calculation.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-11 19:04:52 -08:00
..
alpha [PATCH] capable/capability.h (arch/) 2006-01-11 18:42:14 -08:00
arm [PATCH] capable/capability.h (arch/) 2006-01-11 18:42:14 -08:00
arm26
cris [PATCH] capable/capability.h (arch/) 2006-01-11 18:42:14 -08:00
frv
h8300
i386 [PATCH] x86_64: Fix off by one in acpi table mapping 2006-01-11 19:04:51 -08:00
ia64 [PATCH] capable/capability.h (arch/) 2006-01-11 18:42:14 -08:00
m32r
m68k [PATCH] capable/capability.h (arch/) 2006-01-11 18:42:14 -08:00
m68knommu
mips [PATCH] capable/capability.h (arch/) 2006-01-11 18:42:14 -08:00
parisc [PATCH] capable/capability.h (arch/) 2006-01-11 18:42:14 -08:00
powerpc [PATCH] capable/capability.h (arch/) 2006-01-11 18:42:14 -08:00
ppc [PATCH] capable/capability.h (arch/) 2006-01-11 18:42:14 -08:00
s390 [PATCH] capable/capability.h (arch/) 2006-01-11 18:42:14 -08:00
sh
sh64
sparc [PATCH] capable/capability.h (arch/) 2006-01-11 18:42:14 -08:00
sparc64 [PATCH] capable/capability.h (arch/) 2006-01-11 18:42:14 -08:00
um
v850
x86_64 [PATCH] x86_64: Make udelay more accurate 2006-01-11 19:04:52 -08:00
xtensa