Re: [PATCH] Intel clock speed detection

Nicholas J. Leon (nicholas@binary9.net)
Tue, 23 Dec 1997 18:00:26 -0500 (EST)

# While I haven't looked closely at your patch, did you take
# into account the possibility for a processor not to have the
# cpuid instruction and the rdtsc instruction? You should
# better use the x86_capability member of boot_cpu_info to
# find out.

Ok, sorry to bother you again so quickly, but does something like this
look correct to you? The only place I can find the bitmeanings for
x86_capability is inside of get_cpuinfo (as an array of names). I have to
assume that the flag of "tsc" is rdtsc. Is this assumption correct?

if (!(boot_cpu_data.x86_capability & 16))
/* no rdtsc */

And while we are on it, does anyone else know another method of
determining (relatively accurately) the clock of a chip? It is my
understanding that the UTIME patch can do it, but until it is included in
the mainstream kernel, I'd rather not depend on it (plus it's HUGE for
what I want to do 72K vs. 3K).

TIA!
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simple is elegant nicholas@binary9.net
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