When many processes with large memory usage are started at the same
time, %sys may be high until the working sets are page faulted in, due
to contention on the pcf mutex in page_create_wait. This was observed
when starting hundreds of processes on a M9000-64. lockstat -kW shows:
Count indv cuml rcnt nsec Hottest Lock Caller
-------------------------------------------------------------------------------
1170899 68% 68% 0.00 11444141 pcf page_create_wait
202679 12% 80% 0.00 332996 pcf+0x380 page_free
86959 5% 85% 0.00 8840242 pcf page_reclaim