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    SubjectRe: MSEC_TO_JIFFIES is messed up...
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    On Wed, 12 May 2004 21:33:49 +0200, Ingo Molnar said:
    >
    > * Jeff Garzik <jgarzik@pobox.com> wrote:
    >
    > > >Woah, that's new. And wrong. The code in include/asm-i386/param.h that
    > > >says:
    > > > # define JIFFIES_TO_MSEC(x) (x)
    > > > # define MSEC_TO_JIFFIES(x) (x)
    > > >
    > > >Is not correct. Look at kernel/sched.c for verification of this :)
    > >
    > >
    > > Yes, that is _massively_ broken.
    >
    > why is it wrong?

    If the kernel jiffie is anything other than exactly 1 msec, you're screwed...

    [/usr/src/linux-2.6.6-mm1]2 find include -name '*.h' | xargs egrep '#define HZ '
    include/asm-ppc64/param.h:#define HZ 100
    include/asm-mips/param.h:#define HZ 100
    include/asm-mips/mach-dec/param.h:#define HZ (1 << LOG_2_HZ)
    include/asm-x86_64/param.h:#define HZ 100
    include/asm-ppc/param.h:#define HZ 100
    include/asm-m68k/param.h:#define HZ 100
    include/asm-m68knommu/param.h:#define HZ 1000
    include/asm-m68knommu/param.h:#define HZ 100
    include/asm-m68knommu/param.h:#define HZ 100
    include/asm-m68knommu/param.h:#define HZ 100
    include/asm-m68knommu/param.h:#define HZ 100
    include/asm-m68knommu/param.h:#define HZ 100
    include/asm-m68knommu/param.h:#define HZ 100
    include/asm-m68knommu/param.h:#define HZ 50
    include/asm-m68knommu/param.h:#define HZ 100
    include/asm-parisc/param.h:#define HZ 100
    include/asm-um/param.h:#define HZ 100
    include/asm-sparc/param.h:#define HZ 100
    include/asm-s390/param.h:#define HZ 100
    include/asm-i386/param.h:#define HZ 100
    include/asm-h8300/param.h:#define HZ 100
    include/asm-sparc64/param.h:#define HZ 100
    include/asm-cris/param.h:#define HZ 100
    include/asm-sh/param.h:#define HZ 100

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