Apache+php performance

[ronen]

Hello,
I'm pretty new to Linux and apache admin.
I've set up apache2 on Ubuntu 10.04 with php5 with fastcgi and xcache for opcode caching.
When loading a php page with 1 concurrent connection I'm getting 500ms response time while even few concurrents get worse response times - 2000ms for 5 concurrents (using ab -c5 for testing)
The cpu utilization is ~40% and there ismore than 700MB of free RAM
The server has prefork installed and I've tried changing the mpm settings but it didn't help.
What could be the problem? IS it reasonable to get 4 times slower response times for only 5 concurrent connections?

Thanks!

[jdMorgan]

No, not reasonable at all. One might expect 500mS response times from an overloaded 50MHz i386, but that's way out of line for any modern CPU, even under a heavy load.

I'd suggest simplifying the problem. Back out the add-ons and test. Then tune as well as possible. Then restore one add-on and tune. Lather, rinse, repeat... Divide and conquer.

Unfortunately, that's all I can offer. Hopefully, one of our expert box-tuners will spot this thread after I've bumped it up again... :)

Jim