Windows CPU Allocation

Archived from groups: microsoft.public.windowsxp.perform_maintain (More info?)

We have an application running on Windows XP SP1a that runs in a 24/7 secure
environment. There are other processes running on the terminal however our
application is the main one being used and running all the time.

The application runs with acceptable performance, however after running for
a long period of time (>10 days) the application begins to run painfully
slow.

We've managed to recreate the issue once with performance monitor running
and have discovered that the CPU usage of our application during the slow
performance is very high (85-95%). Nothing different is being done in the
application when this performance becomes slow compared to when it was
faster.

We also discovered that when the performance is slow that if another process
on the system becomes active and requires more resources, that the CPU usage
of our application decreases back to a normal level and performance returns
to normal.

Has anyone experienced a similar issue before? Why would our application
being using more CPU even though no different actions are being performed?
Why would another process requiring resources cause our CPU usage to return
to normal? Any information on how Windows XP allocatea CPU time would be
useful. Does the fact that our application is the main user of resources
cause Windows to give more CPU time than necessary?

The machine it was recreated on is a P3-850MHz with 256MB RAM, however it
has been reported on systems with more memory as well.

Thanks,
Mark Koopman

Archived from groups: microsoft.public.windowsxp.perform_maintain (More info?)

Possibly a memory leak... Windows "forgets" to free up RAM aftera while and
will gradually slow down. Most notable on Win95 and even more so on Win98.
Basically, when some data is deleted from memory, Windows never actually gets
rid of the data, so eventually the computer starts running out of memory.