OpenSolaris

The customer was replacing their dual core amd systems with quad core amd boxes.
They keep these systems behind a load balancer and generally the peak time load
varies from 16 to 25% of cpu time. They have tools that use the %cpu reported by
prstat and uses it for various purposes. After moving to quad core systems they
noticed a sudden dip in the %cpu time reported by prstat. Around 400 systems were
place and majority of them showed this problem while a few of them reported the
%cpu through prstat correctly. On analyzing it i found it indeed is a problem that though
the load is around 20%, prstat reports the httpd process uses only 1 to 2%..
Correlating to mpstat and vmstat output, and also looking at the output of
prstat -m, it's very clear that the cpu utilization % should be definitely much above 1%
(somewhere close 12%). Some of those outputs are attached.

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