On-the-fly throttle of CPU consumption of a process

[sunhux G]

Q1:
When a running process hogs a CPU, I would like to be able to reduce its %
CPU
consumption, say to 50%.  Is there a command to do this or this is possible
in
Redhat (& CentOS & HP-UX if anyone knows) ?

if we started a process / script using "nice", say "nice ./scriptname", it
will give the
process a lower priority (I think) so that other processes will get a higher
priority to use
the CPU  but still a nice process will chew 100% of the CPU when no other
processes
are using it, correct me if I'm wrong.

My purpose is so that we don't get a lot of alerts - having said this, it
makes sense to
tune the monitoring tool's threshold but it takes a while to get the tuning
approved.
I'm looking for quick interim fix to reduce the overwhelming alerts though
this does
not address the root cause.

The best idea I can find so far to achieve this is the link below to put it
in the code as
follows but this is still short of a quick fix :
http://unix.derkeiler.com/Newsgroups/comp.unix.solaris/2006-10/msg01405.html


Q2:
One thought : can a running app (eg Websphere, Weblogic, Tomcat, Oracle
instances)
be set such that it uses only a specific processor in a multiple processor
environment :
the averaged value of all the processors can then show a lower average CPU
utilization.
The other lower CPU hungry process can be shifted to one processor and those
savage ones restricted to 1 or 2 processors : I'm not sure if this manual
reshuffling
is more efficient that letting the system manages it on its own but just
soliciting views.
In some cases, I can't kill or restart resource hungry processes, just
looking for ways
to mitigate the situation