High System Overhead

From: pcoelho3@ibest.com.br
Date: Wed Jul 07 2004 - 13:47:31 EDT

('binary' encoding is not supported, stored as-is) As we can see from collect's output, that our system is totally running for the OS.

# CPU SUMMARY
# USER SYS IDLE WAIT INTR SYSC CS RUNQ AVG5 AVG30 AVG60 FORK VFORK
    33 67 0 0 519 68187 7132 13 21.95 17.31 16.11 132.45 0.20
# SINGLE CPU STATISTICS
# CPU USER SYS IDLE WAIT
      0 30 70 0 0
      1 37 63 0 0
      2 38 62 0 0
      3 36 64 0 0
      4 30 70 0 0
      5 32 68 0 0
      6 35 65 0 0
      7 26 74 0 0

I have searched in the technical tru64 docs ( System Configurationa and Tunning) and Hp related this situation with 4 major possibilities.

- High number of system calls
- High number of interruptions
- High number of IPC calls
- High number of small IOS

Due to the nature of our application, it is more probable, that we have problems with the last one.

But how can I check this ( If I shall use the kernel debugger, how to use it) and say certainly that the problem is really this. And if there is some tunning that I can do in the OS to avoid this situation.

Hp technical manual also talks about a storage feature called "Write-Back Cache" that should be activated. That decreases the latency of small writes.

Someone has already got this situation before and can help me?

Email : pcoelho3@ibest.com.br
  

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