Perf regression in 2.6.32 (Ubuntu 10.04 LTS)

Hello folks,

I've been playing around today a lot with sysbench, and observed that 2.6.32 kernel supplied by Ubuntu is having perf
regressionwith PG (which does not affect MySQL), compared to 2.6.28 builds I have. 
What I observed can be seen in a paste at http://p.defau.lt/?8_GQV82Pz3_SDZbNOdP93Q (db12 is 2.6.28, db20 is 2.6.32 -
2.6.32-24-server). 

Machines are two socket quad-opterons 2356s.

oprofile output can be seen at http://p.defau.lt/?OIR1vDFK4cze_fmBTQbV9w - system has >20% of idle cpu, which is
somewherein the top symbol :) 

Domas