FreeBSD: stressing 4.2 and Apache with ab (fwd)

Richard Smith rdls at
Sun Dec 31 22:10:05 GMT 2000

"L. Cranswick" wrote:
> Do you have the parameters you have tweaked to make a
> "robust" kernel?  Can you post the relevant parts of
> the config files that could also be included on the web?

The only significant change from the GENERIC kernal configuration file

maxusers	512

The only reason that I chose the value of 512 was that it was the
maximum value allowed (a warning is issued by config(8) if you try to
set maxusers larger than 512).

I have extracted a few values using `sysctl -a' to demonstrate how the
entire system scales with maxusers=512:

kern.ipc.nmbclusters: 8704
kern.ipc.nmbufs: 34816
kern.maxfiles: 16424
kern.maxfilesperproc: 16424

It may well be that you have an application or benchmark that requires
more NMBCLUSTERS than 8704, in which case you could make additional
changes in your `/etc/sysctl.conf' file. However, I must admit that I
perfer scaling the entire system using maxusers rather than tweeking
specific parameters to suit a particular benchmark.

My objective has always been to build a "robust" kernel, rather than the
optimum kernel for a specific application, indeed, one could fiddle with
many parameters to obtain the maximum performance or the minimum memory

Most of my systems are currently 400MHz Celerons with 128M of RAM,
running mainly my own code. However, I will soon be deploying some
Apache web servers on the Internet using more extreme platforms, so I
look forward to reading your final conclusions in the not too distant

Best regards,

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