Signal Handling Performance?

[Carey B. Stortz]

I am doing a research project on Linux kernel performance starting with the
2.0.1 kernel through the 2.4.0 kernel. I ran across something very
interesting when running LMBench and reviewing the results. The performance
of Signal Handling has decreased while every other area has either stayed
the same or had a performance increase. A general decrease started around
kernel 2.1.32, then performance drastically fell at kernel 2.3.20. There is
an Excel graph which shows the trend at:

http://euclid.nmu.edu/~benchmark/Carey/signalhandling.gif

I was wondering if anybody had any ideas why this is happening, and what
happened in kernel 2.3.20 to cause such a decrease in performance?

Thanks for your time
Carey Stortz