sysctl hw add nphyscpu variable

[Richard Yao]

On Mon 04 Aug 2014 07:53:42 AM EDT, Stefan Parvu wrote:
> Hi,
>
> Would be possible to have under sysctl interface a new variable which will track the
> number of physical CPU sockets a system has ? Would be useful for hardware
> and data inventory.

It should be.

> Something like:
>
> hw.machine: amd64
> hw.model: Intel(R) Xeon(R) CPU E5-2640 v2 @ 2.00GHz
> hw.ncpu: 32
> hw.nphyscpu: 2
> ^^^^^^^^^^^^

I think hw.nsocket would make more sense. Whoever does this should 
check to see if any other UNIX platforms have picked a suitable name.

> This is an example from my system with two 2 physical CPUs installed. No system
> virtualization in place, like Xen, etc ...
>
> Or is it possible currently to get easily this information ? I havent found one
> except dmesg information.
>
> FreeBSD/SMP: Multiprocessor System Detected: 32 CPUs
> FreeBSD/SMP: 2 package(s) x 8 core(s) x 2 SMT threads
>  cpu0 (BSP): APIC ID:  0
>  cpu1 (AP): APIC ID:  1
>  cpu2 (AP): APIC ID:  2
>  cpu3 (AP): APIC ID:  3
>  cpu4 (AP): APIC ID:  4
>  cpu5 (AP): APIC ID:  5
>  cpu6 (AP): APIC ID:  6
>  cpu7 (AP): APIC ID:  7
>  cpu8 (AP): APIC ID:  8
>  cpu9 (AP): APIC ID:  9
>  cpu10 (AP): APIC ID: 10
>  cpu11 (AP): APIC ID: 11
>  cpu12 (AP): APIC ID: 12
>  cpu13 (AP): APIC ID: 13
>  cpu14 (AP): APIC ID: 14
>  cpu15 (AP): APIC ID: 15
>  cpu16 (AP): APIC ID: 32
>  cpu17 (AP): APIC ID: 33
>  cpu18 (AP): APIC ID: 34
>  cpu19 (AP): APIC ID: 35
>  cpu20 (AP): APIC ID: 36
>  cpu21 (AP): APIC ID: 37
>  cpu22 (AP): APIC ID: 38
>  cpu23 (AP): APIC ID: 39
>  cpu24 (AP): APIC ID: 40
>  cpu25 (AP): APIC ID: 41
>  cpu26 (AP): APIC ID: 42
>  cpu27 (AP): APIC ID: 43
>  cpu28 (AP): APIC ID: 44
>  cpu29 (AP): APIC ID: 45
>  cpu30 (AP): APIC ID: 46
>  cpu31 (AP): APIC ID: 47

Whoever implements this would want to find the code that prints this 
and use the information to initialize the sysctl variable.

> Probable things will get complicated a bit if the system is a guest under Xen or other
> hypervisor. But probable there the nphyscpu should be NA ?

The hypervisor is able to pass through a geometry, so this would still 
make sense there.

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