Slackware 9.1 + 2GB memory critical performance loss
I have very bad problems with 2GB memory. I have a webserver
(mainboard is ASUS P400, INTEL P4, IDE discs) and MySQL database, with not so big load.
When I have 1GB of memory activated, it works like charm. However when I activate 2nd GB of RAM, machine suffers terrible performance loss while accessing I/O hard disc functions. THis results into constant load of apache as 99% and unusable system. Unfortunately the web sites requires that much of memory - 1.5GB for standard load (don't ask me why, I only take care about the server. :) )
What I've tried so far:
1, linux kernel from Slackware 9.1 CD (with compiled High memory ON)
2, vanilla kernel 2.4.25 up to 2.4.27 with both High Memory Support set to 4GB and Highmem I/O support
3, vanilla kernel 2.4.23 with Andrea's buffer bounce patch version aa3 which was supposed to solve the problem. There I set User address space size to 2GB
Memory is definitely OK, I put it on hardware tests and it passed. Also drves are ok.
Please if anyone knows how to help or advice, I'd be glad. I usually don't ask but this is an emergency and I'm stuck with this over two months now.
Thanks a lot
Ps. the performance loss is not only the apache. eg. kernel compilation is more than 10 times slower with 2GB of memory on.