Re: Processor cores not properly detected/activated?

From: Alan Somers <asomers_at_freebsd.org>
Date: Fri, 23 May 2014 21:03:12 -0600
On Fri, May 23, 2014 at 8:42 PM, Tim Bishop <tim-lists_at_bishnet.net> wrote:
> On Fri, May 23, 2014 at 08:07:03PM -0600, Alan Somers wrote:
>> On Fri, May 23, 2014 at 7:47 PM, Tim Bishop <tim-lists_at_bishnet.net> wrote:
>> > I have a new quad CPU system containing four of these processors:
>> >
>> > Intel(R) Xeon(R) CPU E7-4830 v2 _at_ 2.20GHz (2200.05-MHz K8-class CPU)
>> >
>> > I've tried FreeBSD 10.0, stable/10 and head, but all of them only detect
>> > a maximum of 64 "CPUs". There should be 80. Here's the relevant dmesg
>> > output (full output attached):
>> >
>> > FreeBSD/SMP: Multiprocessor System Detected: 64 CPUs
>> > FreeBSD/SMP: 3 package(s) x 10 core(s) x 2 SMT threads
>> > ...
>>
>> Try setting MAXCPU higher.  It's defined by default to 64 in,
>> sys/amd64/include/param.h
>
> Ah! Thank you, yes, that fixed it:
>
> FreeBSD/SMP: Multiprocessor System Detected: 80 CPUs
> FreeBSD/SMP: 4 package(s) x 10 core(s) x 2 SMT threads
>
> Given the number of "CPUs" in some top end processors (up to 30 per
> socket), a limit of 64 is starting to seem low. Is it worth doubling it
> to 128? Or even higher?

Yeah, I think so.  It seems like a GENERIC kernel ought to be able to
handle the biggest commonly available quad socket systems.  Anything
with more than 4 sockets, though, is probably too exotic to deserve
such special treatment.

>
> It'd be nice to be able to use a stock kernel with freebsd-update at
> least.
>
> Anyway, thanks for your help Alan, at least my system is working fully
> now :-)
>
> Tim.
>
> --
> Tim Bishop
> http://www.bishnet.net/tim/
> PGP Key: 0x6C226B37FDF38D55
>
Received on Sat May 24 2014 - 01:03:14 UTC

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