Messages in this thread | | | Date | Wed, 28 May 2008 19:57:11 -0400 | From | "Lee Revell" <> | Subject | Re: mmap over HPET - 32 bit wrap arround |
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On Wed, May 28, 2008 at 6:19 PM, Raz <raziebe@gmail.com> wrote: > I am wondering wether someone can explain how hpet behaves. The bellow > is a short program that reads from a mmaped /dev/hpet the time. I am > running it and it looks that afer ~296 seconds the counter resets . I > AM RUNNING 64bi KERNEL(2.6.18-8.el5) and reading a 64BIT VARIABLE. > my hpet is 14MHZ, so I am guessing a 32bit wraparound ( ~296 * 14Mhz > ) = MAX_INT . but why ? >
HPET counter can be either 32 or 64 bit. Check COUNT_SIZE_CAP.
http://www.intel.com/hardwaredesign/hpetspec_1.pdf
Lee
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