How to get - number of threads per process?

Try this:

ps axo pid,ppid,rss,vsz,nlwp,cmd 

Output columns:

• pid - Process ID
• ppid - Parent Process ID
• rss - Resident Set Size - physical memory
• vsz - Virtual Set Size - virtual memory
• nlwp - Number of Light Weight Processes - thread count
• cmd - Command

Use the following to show the memory use of a single process:

pmap -d <PID> 

Try this little hamster in Perl for a simple system overview (on Linux):

http://public.m-plify.net/apercu/apercu.pl

Groups processes by name, e.g. all the processes named "httpd" go into one line; or a special process is given its own line.

For each group give:

• total CPU usage used (percent of single CPU, so the total can be over 100%)
• total mem usage used (percent)
• total 'rss', 'size', 'sz', 'vsz' used (from 'ps')
• total number of processes grouped
• total number of threads managed by the grouped processes
• total number of file descriptors used by the processes grouped ("FILES")
• total number of internet sockets used (that value is already included in "FILES")
• total number of unix domain sockets used (that value is already included in "FILES")