[PATCH] AMD multicore detection

Colin Percival cperciva at freebsd.org
Wed Sep 21 23:47:03 PDT 2005

Martin Nilsson wrote:
> Jung-uk Kim wrote:
>> New patch is here:
>> http://people.freebsd.org/~jkim/multicore.diff
>> Please test and let me know.  I don't have multicore CPU to test it
>> for myself. :-(
> The below is on a Pentium D 820 (Dualcore). I don't like that the two
> cores are reported as hyperthreading when the CPU does not support
> hyperthreading (only the 840 EE does). If we ship 6.0 with HT disabled
> I'm afraid that it will turn off one of the cores, right?

It shouldn't.  Dual-core processors claim to be hyperthreaded, but when
I wrote the patch which disabled hyperthreading I added extra (and rather
complicated) code to detect dual-core processors and *not* disable them.

If I got it wrong, please let me know. :-)

Colin Percival

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