DBT2-MySQL Benchmark. "hugemem" vs "smp" kernels

Hi,

Some half a year ago I wrote about my experience of performance of "hugemem" vs "sm" kernels for 2.4.21-9.EL kernel from RH AS 3.0

The results I got previously were

                 smp          hugemem 
IO BOUND:      1450TPM        1250TPM
CPU BOUND:     7000TPM        4500TPM

Results are in Transactions per Minute.

This was significant regression and it was some kind of expected.

The results with newer kernel 2.4.21-15.EL are very strange however:

                 smp          hugemem 
IO BOUND:      1150TPM        1650TPM
CPU BOUND:     6300TPM        5000TPM

Well I'm pretty happy to see "hugemem" kernel improved a lot, but what happened with SMP kernel ? Why it is slow now for IO bound case and why it became slower than 2.4.21-9.EL ?

I'm using 4*Pentium Xeon 2.0Ghz w HT, 4GB RAM, 3WARE RAID10, EXT3

Peter Zaitsev, Senior Support Engineer
MySQL AB, www.mysql.com