Messages in this thread | | | Date | Tue, 07 Sep 2004 14:42:06 -0700 | From | George Anzinger <> | Subject | Re: [RFC] New Time of day proposal (updated 9/2/04) |
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Christoph Lameter wrote: > On Tue, 7 Sep 2004, George Anzinger wrote: > > >>Also, we don't "know" what rate the TSC is actually clocking so we must >>"discover" it at boot time. This process either is inaccurate or slow (I think >>we use ~ 50 ms these days which gives an error of ~10 TSC cycles on a 800MHZ >>box). FWIW the problem here is the sync up with the I/O backplane to find the >>start and ending of the measured time. >> >>I suspect that the IA64 "tells" you what its clock rate is. Right? > > > Not the CPU itself. There is a special hardware I/O interface called the > PAL/SAL that allows one to retrieve that information. Doesn't the BIOS on > i386 allow you to get to that information?
Not as far as I know. If it did we would kick out the calibrate loop and boot some 50ms faster (always a good thing). Could be somebody else has better info here...
-- George Anzinger george@mvista.com High-res-timers: http://sourceforge.net/projects/high-res-timers/ Preemption patch: http://www.kernel.org/pub/linux/kernel/people/rml
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