[CentOS] Confirming Multi-Processor

Lamar Owen lowen at pari.edu
Tue Nov 28 16:42:11 UTC 2006

On Monday 27 November 2006 20:51, Jack Murgia wrote:
> I have a test bed server that's pretty old- PIII Dual 550. I've done yum
> update kernel-smp and when I run cat/proc/cpuinfo it lists both processors-
> is there anything I need to to to confirm that it's fully utilizing both
> processors?

Ok, I know this is going to sound long and unnecessary, but I've found that a 
really good tool for seeing multiprocessor activity is gkrellm.  I normally 
run this through an ssh-forwarded X session rather than using the server's 
display.  This is available in at least a couple of the extra repositories 
for CentOS, including Dag's and Karanbir's (dag.wieers.com and 
centos.karan.org).  Add whichever extra repo you want, following instructions 
(I have lately been using the karan.org repo), and yum install gkrellm. Just 
be careful and only use one or the other; Dag and kbs-CentOS-Extras have 
overlapping and not necessarily compatible sets of packages. Either one 
works; I have servers using Dag, and servers using kbs-CentOS-Extras.

To use it, tunnel into the box with 'ssh -Y' and run gkrellm from the command 
line.  I have one box I use here for a display server, with multiple ssh 
sessions to my various servers; when people look at the gkrellm displays for 
two of my boxes, they have to take a double-take: I have a Sun E6500 with 10 
CPU's and a Sun E5500 with 8 (both are running Aurora Linux, although I hav a 
test install on the E6500 of Ubuntu Server), and the gkrellm display for that 
many CPU's is just too cool.  Spacely, the E5500, is even funkier, with 22 
SCSI hard drives in a couple of RAID5 devices: gkrellm can give you graphs of 
disk throughput on an aggregate and/or and individual device basis.  Watching 
RAID accesses be striped across the component devices is pretty fun, 
particularly on the one 14 drive (36G 10K RPM drives; the aggregate 
throughput across the three diff-UWSCSI channels is over 100MB/s) md.

Watching the kernel swap processors is enlightening; I also have a dual Xeon 
Dell PE 2850 here, and when I run a processor-intensive single-threaded app, 
watching the load switch between the two procs every 5 seconds in fun.

That is the thing gkrellm is nice for; once getting started using it, I've put 
it on every Linux box I have.  It can also run in a client-server mode; 
Windows servers can run a gkrellm server process, too, and you can watch a 
Windows box on a Linux box running the gkrellm client.  I use it for 
bandwidth measurements, among other useful things.  It's certainly worth 
looking at as a real-time trend-watching display; and it's especially great 
for the 'blinkenlights' crowd.
Lamar Owen
Director of Information Technology
Pisgah Astronomical Research Institute
1 PARI Drive
Rosman, NC  28772

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