Re: Detecting SMP

[Mike A. Harris]

On Tue, 20 Feb 2001, Burton Windle wrote:

>Hello. Is there a way, when running a non-SMP kernel, to detect or
>otherwise tell (software only; the machine is 2400 miles away) if the
>system has SMP capibilties? Would /proc/cpuinfo show two CPUs if the
>kernel is non-SMP?  Thanks!
>
>(btw, the kernel in question is a stock RH6.2 kernel 2.2.14-5, and yes, I
>know I should update it anyways and that a SMP kernel will run on a UP
>system)

Yes, there are several ways.  How do you want to know how to do
it, in C, or a bash script?  sysconf is one way, parsing
/proc/cpuinfo and /proc/stat is another.  Beware though, if you
parse /proc/cpuinfo or stat, it is very different on different
architectures, particularly sparc.

Here is some code which should do it more or less correctly on
any arch:

ncpus=$(egrep -c ^cpu[0-9]+ /proc/stat || :)
[ "$ncpus" = "0" ] && ncpus=1

----------------------------------------------------------------------
    Mike A. Harris  -  Linux advocate  -  Free Software advocate
          This message is copyright 2001, all rights reserved.
  Views expressed are my own, not necessarily shared by my employer.
----------------------------------------------------------------------
if (argc > 1 && strcmp(argv[1], "-advice") == 0) {
    printf("Don't Panic!\n");
    exit(42);
}