---
date: "2002-01-16T14:15:59Z"
title: Kernel Fun
---

<p>

This weekend I decided to upgrade from my trusty 2.4.16 + <a href="http://www.kernel.org/pub/linux/kernel/people/rml/preempt-kernel/">preempt</a> to
something a bit more recent.  The first thing I tried was 
<a
href="http://www.kernel.org/pub/linux/kernel/v2.4/testing/patch-2.4.18.log">2.4.18-pre3</a> +
<a
href="http://www.kernel.org/pub/linux/kernel/people/rml/preempt-kernel/v2.4/ingo-O1-sched/">O(1) + preempt</a> + <a href="http://www.kernel.org/pub/linux/kernel/people/rml/lock-break/">lock-break</a>,
which fell over miserably on my system (eg if it didn't panic at boot I
could consistently cause a panic with a <code>gmake -j5</code>).  After
some "testing" on
<a href="http://www.kernelnewbies.org/">IRC</a> with
<a href="http://tech9.net/rml/">Robert Love</a> (ie, boot, wait
until panic and hard lock, write entire panic on piece of paper, reboot
into stable kernel and type up panic, post panic to web for Robert to
run ksymoops on, apply patch to kernel, reboot, repeat), I finally
decided to take a break from
<a href="http://www.kernel.org/pub/linux/kernel/people/rml/preempt-kernel/">preempt</a>
for the week and give <a href="http://www.zip.com.au/~akpm/linux/schedlat.html#downloads">low latency</a> a shot.  I'm running
<a
href="http://www.kernel.org/pub/linux/kernel/v2.4/ChangeLog-2.4.17">2.4.17</a>
+ <a href="http://www.surriel.com/patches/">rmap</a> +
<a href="http://people.redhat.com/mingo/O(1)-scheduler/">O(1)</a> + <a href="http://www.zip.com.au/~akpm/linux/schedlat.html#downloads">low latency</a> now, and it
seems to be pretty stable.  I'll try out <a href="http://www.kernel.org/pub/linux/kernel/people/rml/preempt-kernel/">preempt</a> + <a href="http://www.kernel.org/pub/linux/kernel/people/rml/lock-break/">lock-break</a> again
this weekend and let everyone know what happens.  By the way, the
problems I mentioned above with <a href="http://www.kernel.org/pub/linux/kernel/people/rml/preempt-kernel/">preempt</a> have to do with SMP and
preemption near interrupts -- all you single-processor users have
nothing to fear.
</p>

<p>

There has been a really amusing thread on the LKML for the last few
weeks regarding automatic kernel build configuration.  The thread
started as a question from <a href="http://www.tuxedo.org/~esr/">ESR</a> about probing the ISA bus, and progressed
(devolved?) into an amusing war of metaphors between <a href="http://www.linux.org.uk/diary/">Alan Cox</a> and <a href="http://www.tuxedo.org/~esr/">ESR</a>.
Essentially, <a href="http://www.tuxedo.org/~esr/">ESR</a> used a hypothetical "Aunt Tillie" to represtent the
typical technology-impaired "mom and pop" Linux user, who, for some
unspecified reason, opts to compile her own kernel instead of  using the
modular vendor-supplied, vendor-tested, and vendor-supported version.
After the Aunt Tillie scenario made relatively little progress against
<a href="http://www.linux.org.uk/diary/">Alan Cox</a> and a handful of other people, <a href="http://www.tuxedo.org/~esr/">ESR</a> added "Nephew Melvin" to the
list of hypothetical characters.  Anyway, <a href="http://www.linux.org.uk/diary/">Alan Cox</a>'s latest contribution
to the argument:

</p>

<p>
<pre>
From: Alan Cox &lt;alan@aunt-tillie.org&gt;
...
pabs@gw-uunet:~&gt; whois aunt-tillie.org
...
Registrant:
  Melvin?  What do I type here?
  10 Alan Turing Road
  Surrey Research Park
  Guildford, Surrey GU2 7YF
  UK
</pre>
</p>

<p>
Be sure to check out
<a href="http://www.aunt-tillie.org/">http://www.aunt-tillie.org/</a>
as well.
</p>