8.1-PRERELEASE: CPU packages not detected correctly
avg at icyb.net.ua
Fri Aug 27 19:47:16 UTC 2010
on 27/08/2010 22:36 Jung-uk Kim said the following:
> Now, back to my original question. My point was, we should never
> trust any CPUIDs on emulated CPU if they are translated. What should
> happen if you have four physical cores and you "assign" just one for
> VirtualBox, for example? What should we "announce" if you are
> emulating two cores on UP host? How do we know whether it is "the"
> real BSP or not? Is it really bound to a CPU? Is "CPUID leaf 11"
> emulated properly? If not, is it an emulator bug or a guest OS bug?
> Do we really care about "physical topology" in these cases? IMHO,
> the answer is no, we don't, and we should say "all cores are
> independent". If anyone really cares and wants prettier printing, we
> may say "N virtual cores", though.
Thanks a lot for the rest of the info that I snipped, very interesting and useful!
To this issue - I'd say let the developers of virtual machines worry that their
machines look like real hardware, not us.
More specifically, in this thread we saw that current FreeBSD code (without the
patch) and Intel's code detect the same topology and that topology looks
reasonable for the person who started the thread. With the patch though,
detected topology looks different.
So I'd rather not worry about the general case of virtual machines right now.
Let's first see more evidence of whether we should trust them or not.
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