"Now that we have all these independent kernel trees,
which one should we use? Which kernel is faster? Which ones are
more reliable and which ones are bound to cause you problems? I set
out to answer these questions for myself, so I downloaded the two
most controversial kernel types (the standard kernel/Andrea
Arcangeli type and the Alan Cox/Rik van Riel kernel type) and
pitted them against each other. Andrea Arcangeli has his own aa
tree, but for most purposes it is very similar to the standard
Linux tree. That's because the virtual memory engine in the
standard Linux was actually written by Andrea Arcangeli and
improved by Ben LaHaise, Linux Torvalds, Andrew Morton, Alan Cox,
and Marcelo Tosatti (the 2.4.x maintainer), among others.
On the other hand, the Alan Cox 2.4.18pre3 ac tree is the
improved version of the first 2.4. kernels (from 2.4.0 to 2.4.9)
with significant enhancements in the VM (Virtual Memory) area. As
you might remember, up to Version 2.4.10, too many people were
complaining about the poor performance and the poor reliability of
the VM engine. Problems like swap storms and degrading performance
were easily reproducible. See my October 2001 column on this
subject.
Before even starting to test the various kernels, I asked Alan
Cox, Andrea Arcangeli, and Rik van Riel what they thought would be
a good test, and for any tuning preferences they might have. Both
Alan Cox and Andrea Arcangeli wrote back with elaborate advice and
opinions, while Rik restricted himself to question whether the
standard Linux kernel would ever even finish a stress test. Andrea
Arcangeli and Alan Cox were very helpful and provided advise, code,
and comments. Alan Cox even went so far as to offer to find a
company that would let me run benchmarks on its servers and
software."
