Q: How do you verify that Linux is using both processors?

We just got in a new system with Red Hat 5.2 and dual processors. I cannot verify that both processors are being used. I usually use the utility "top" to show that both processors are being used, but "top" is showing only one. I'm not sure if this is a limitation of Linux's "top".

A: Since v. 2.0.7, Michael K. Johnson as the new maintainer of the procps package (which includes top) has included the SMP patch. Sources are available from ftp://people.redhat.com/johnsonm/procps/

Previous versions of top won't show two CPUs. However, the information shown there is still valid. There is an SMP-enabled utility you might consider, named xosview, which has a patch that will graphicly display what you need. xosview:

http://xosview.sourceforge.net/

Alternatively, check /proc/cpuinfo or look at /var/log/dmesg . (Search for Bogo.)

/var/log/dmesg:
Booting processor 0 stack 00002000:
Calibrating delay loop.. ok - 398.13 BogoMIPS
Total of 2 processors activated (795.44 BogoMIPS).
Booting processor 0 stack 00002000:
Calibrating delay loop.. ok - 398.13 BogoMIPS