If it has been determined that the system is CPU
bound, there are a number of things that can be done:
If possible, consider rescheduling the existing
job load on your system.
If many large jobs are being run at once, rescheduling them
to run at different times may improve performance.
You should also check the system's
crontab(C)
files to see if any jobs running at
peak times can be scheduled to run at other times.
If possible, tune the applications so that they use require
less CPU power. Consider replacing non-critical
applications with ones that require a less powerful system.
If you have evidence that the system is I/O bound serving
interrupts from non-intelligent serial cards,
replacing these with intelligent serial cards will offload
some of the I/O burden from the CPUs.
See
``Serial device resources''
for more details.
Check if the hard disk controllers in the system are capable of using
DMA to transfer data to and from memory. If the
CPU has to perform programmed I/O on behalf
of the controller, this can limit its performance.
It is possible that because of a lack of free memory the
system is swapping, which could result in a considerable
portion of the CPU resources being used to
transfer processes back and forth between the disk and
memory.
To determine if this is the case see the section
Chapter 4, ``Tuning memory resources''.
Upgrade to a faster CPU or CPUs.
Upgrade to a multiprocessor system from a single processor system.
This will help if there are runnable jobs on the run queue or the
applications being run are multithreaded.
Add one or more CPUs to a multiprocessor system.
Purchase an additional system and divide your processing
requirements between it and your current system.