[CentOS] too much cpu system time with kernel 2.6.9-22.0.2.EL
lowen at pari.edu
Thu Mar 9 18:24:15 UTC 2006
On Wednesday 08 March 2006 11:18, David Mansfield wrote:
> The system is slow, relatively (866Mhz cpu) and the network is fast
> (gigabit) so the limiting factor should be CPU.
What is the actual throughput on the GigE? What KIND of GigE? Which driver?
> However, at times, the system gets into a 'weird' state where instead of
> using about 85% user/ 15% system, it goes to 50% user and 50% system.
> Now 50% system time for this load is ridiculous, and as I said before,
> most of the time it is 85/15 and only occasionally get's 'stuck' in
> CPU: CPU with timer interrupt, speed 0 MHz (estimated)
> Profiling through timer interrupt
> samples % symbol name
> 21117 36.5340 default_idle
> This is CRAZY! How can default_idle be sucking away cycles when the
> system is (should be) cpubound?
> Can anyone explain this?
GigE DMA, perhaps?
DMA time would show as cpu idle, I would think.
Bus contention between the GigE and the disk? (Servers have split buses for a
reason...and PCIe is a switched architecture for a reason)
Director of Information Technology
Pisgah Astronomical Research Institute
1 PARI Drive
Rosman, NC 28772
More information about the CentOS