Krista said:
My windows xp "system" process just started running 100 % cpu all the time
it . it dose it in safe mode also I have checked for virus and spyware
nothing. I haven't installed any new hardware or software. when I do a
process explore it still show system and DPC take all the avaiable cpu up to
100%. nothing under system show any cpu usage. Please help
DPCs are normal. They're a way of running code at a user level
rather than at a kernel level. One usage for a DPC might be
to complete the handling of an interrupt from some hardware.
So if you see an abnormal number of DPCs, it could be from
an "interrupt storm". That happens if a piece of hardware is
sending interrupts continuously for no good reason.
If you go to Settings:Control Panels:Administrative Tools
erformance,
you can add counters to the Performance panel such as "Interrupts/Sec"
and "DPCs Queued/sec". That may give you some idea whether you're
dealing with a storm or not. (You may have to do Properties in the
resulting graph, and change the vertical scale to a higher number, in
order to see the graph.) You can try disabling optional pieces
of hardware one at a time, and see if it makes a difference, but then
there are going to be some items you can't disable, without causing
problems.
As a test here, I can start a 3D game, then alt-tab out of the
game and return to the Windows Desktop. If I do that, my interrupt
rate is 2100 interrupts/sec, while my DPC rate is 1527 DPCs/sec.
So that would be considered a "normal" level, for a certain kind
of application. If you were seeing 10000+ rates per second, then that may
be telling you there is a hardware issue.
Shutting down, and unplugging the computer for five minutes, then
rebooting, may result in the storm going away. But a hardware issue
like that, could come back at any time.
Paul
