question about sched_ule and sched_4bsd

[Stefanita Rares Dumitrescu]

ok guys i have something very puzzling:

i am using 
nginx-0.8.53/php-fpm-5.2.14/eaccelerator-0.9.6.1/freebsd-8.1-latest-pl

i upgraded the system from freebsd7, and on my old freebsd7 system, i 
was running SCHED_4BSD. the server worked rather ok, however, when i 
switched to bsd 8.1, i decided to try sched_ule, and bummer, the server 
load was shooting through the roof, the php-cgi processes were almost 
constantly in RUN state, and basically the system was unusable for heavy 
load.

i am talking about a dual xeons / 16 gb ram machine here.

anyway i recompiled the kernel, and got back to SCHED_4BSD, but i would 
just want to know if anyone has any experience and advice with this, and 
why the schedulers performance difference.

cheers