Performance degradation on 2.6.25 kernels for http servers
Subsystems (2)
We noticed something strange today.
We have a test that launches 10 http clients that request a small URL over and over again. Keep-alive is enabled on clients and apache.
When using a 2.6.24 or earlier kernel on the web server, we get around 1200 urls per second completed on each of the 10 clients. With 2.6.25 kernel we get around 1000 urls per second completed. In other words, about a 20% degradation in connections per second.
We see the same affect when we use standard Fedora kernels as when
we use our own patched kernels. We see similar degradations when using FC5 and FC8, and 32-bit and 64-bit installs. We see similar degradations on different hardware systems. We have only tried our modified kernels and standard Fedora kernels at this time (no un-modified kernels from kernel.org).
It could still be something we are doing wrong, but if anyone else has a similar test case, I'm curious to know if you see similar degradations.
Thanks,
Ben
Signature · 2 lines
Ben Greear <[email protected]> Candela Technologies Inc http://www.candelatech.com
Do you have the same configuration?
2008/7/23 Ben Greear <[email protected]>:
Quoted 35 lines
We noticed something strange today.
We have a test that launches 10 http clients that request a small URL over and over again. Keep-alive is enabled on clients and apache.
When using a 2.6.24 or earlier kernel on the web server, we get around 1200 urls per second completed on each of the 10 clients. With 2.6.25 kernel
we get around 1000 urls per second completed. In other words, about a 20% degradation in connections per second.We see the same affect when we use standard Fedora kernels as when we use our own patched kernels. We see similar degradations when using FC5 and FC8, and 32-bit and 64-bit installs. We see similar degradations on different hardware systems. We have only tried our modified kernels and standard Fedora kernels at this time (no un-modified kernels from kernel.org).
It could still be something we are doing wrong, but if anyone else has a similar test case, I'm curious to know if you see similar degradations.
Thanks,
Ben--
Ben Greear <[email protected]>
Candela Technologies Inc http://www.candelatech.com--
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Quoted 1 line · Tobias Koeck
Do you have the same configuration?
I'm not sure I understand the question.
We were booting into one kernel, running the test, and then rebooting with a different kernel. There were no other changes to any config files or settings that I am aware of.
I'll try a git-bisect when I get a chance...
Thanks,
Ben
Signature · 2 lines
Ben Greear <[email protected]> Candela Technologies Inc http://www.candelatech.com