Re: NSProcessInfo -processorCount, -activeProcessorCount, -physicalMemory

[David Chisnall]

On 13 Nov 2008, at 12:49, Pete French wrote:

> > This too is a system specific solution, but at least we use glibc
> > instead of doing the parsing ourselves. This should save us the  
> > problem
> > of adopting to a new kernel every time.
> >
> > We still will need different solutions for non-Linux systems.
>
> isn;'t there some kind of standard for these things ? Over in FreeBSD
> land /proc has been depracated for a couple of years and no longer
> appears by default. I dont ever look at this part of the kernel,
> but I wwas under the imppression there was a rough set of standardised
> calls to replace all this on Unix/BSD at least. So we could use /proc
> on Linux/Plan9 style things and the aalternative on Unix/BSD system
> maybe ?

Ooops - my last reply was sent just to Fred, not to the list.

In *BSD these are all done via sysctls, which are a much cleaner  
interface than parsing a big blob of text (which, in Linux's case, has  
a different format on different architectures).  In Étoilé's  
SystemConfig framework you will find a set of simple wrappers that  
call a sysctl by name and return either an NSString or an integer:

http://svn.gna.org/viewcvs/etoile/stable/Frameworks/SystemConfig/Source/TRSysctlByName.h?rev=3718&view=auto

There are examples using these to find the amount of memory, CPU name,  
and CPU speed for various platforms here:

http://svn.gna.org/viewcvs/etoile/stable/Frameworks/SystemConfig/Source/

There is also a Solaris implementation (which uses different  
interfaces) in the same directory.

Getting the number of CPUs is just a matter of using a different  
sysctl.  On FreeBSD, OpenBSD, and Darwin, "hw.ncpu" gives the total  
number of CPUs.  On FreeBSD, kern.smp.cpus seems to give the number of  
active CPUs and on Darwin hw.activecpu does the same.

David