HPWS Apache 2.0.58 on HPUX 11.23 PA-RISC

[RJ-CMI]

Just upgraded from Apache 1.3.37 to Apache 2.0.58 on a HPUX 11.23 PA-RISC system and noticed HIGH CPU utilization with the same amount of web load as before. The apache configuration is set to run 25 threads per process (which is the minimum recommended) and one of the threads is taking 1 whole CPU. The same thread seems to be making a lot of poll system calls. The server has 8 CPUs. We tried with both the HPWS apache 2 version as well as the version from apache.org. The thread seems to be changing status from CACHE to PRI(waiting for priority).
Has anyone seen this behavior before? Does this have to do with any specific Kernel parameters?