High Apache CPU Load

[komodo9]

Hi,

I've search around quite a bit, but I can't seem to find a clear answer.

I've turned on mod_status, and on the status page, I'm worried Apache is being overworked.

CPU Usage: u334.883 s94.5703 cu177.422 cs0 - 43.3% CPU load
54.1 requests/sec - 181.5 kB/second - 3435 B/request
178 requests currently being processed, 52 idle workers
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At the time I took this particular snapshot, it's not near its peak... it's not uncommon for the CPU load approach 60%. Reading around, it seems the CPU load should normally be under 1% (such as 0.0139% or what-not). Is this true?

The weird thing though... I have no idea where that number is coming from, because according to "top", the CPU is actually 90% idle.

Here is my Apache MPM settings:

ServerLimit 512
<IfModule mpm_prefork_module>
  StartServers     10
  MinSpareServers   15
  MaxSpareServers   50
  MaxClients     1024
  MaxRequestsPerChild  0
</IfModule>

I actually just raised the MaxClients from 512 to 1024 because I was hitting a constant cap of 40 requests/sec... and I was worried it was going to bottleneck. When I raised that value, the max requests per second now seem to be freed up.

If the actual CPU of the server is 90% idle... am I okay? Anyone know where Apache's getting the CPU Load info from? Any recommendations for optimization?

Thanks everyone!