FreeBSD vs Ubuntu - Discuss...

Andrew Kuriger a.kuriger at
Tue Sep 29 18:20:51 UTC 2009

On Mon, 28 Sep 2009 19:26:34 PDT, Dieter <freebsd at>
> In message <cone.1254181613.595484.57677.1000 at>,
> Francisco Reyes writes:
>> Steven Hartland writes:
>> > Just noticed the following posted on phoronix:
>> >
>> > Comments?
>> This was discussed in detail in slashdot.. starting with the fact that
>> most
>> likely debug switches were not turned off for FreeBSD.
> "All of the FreeBSD and Ubuntu options were left at their defaults."
> My question is why is FreeBSD's disk i/o performance so bad?
> Not just in the benchmarks with debugging on, but in real world usage
> where it actually matters.
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Well for one if we look at /usr/src/UPDATING

FreeBSD 8.x has many debugging features turned on, in both the kernel and
userland. These features attempt to detect incorrect use of system
primitives, and encourage loud failure through extra sanity checking and
fail stop semantics. They also substantially impact system performance. If
you want to do performance measurement, benchmarking, and optimization,
you'll want to turn them off. This includes various WITNESS- related kernel
options, INVARIANTS, malloc debugging flags in userland, and various
verbose features in the kernel. Many developers choose to disable these
features on build machines to maximize performance. (To disable malloc
debugging, run ln -s aj /etc/malloc.conf.)"

Since the article says that they left the debugging features on I think
this has a bit to do with it. Obviously the testers didn't care to read the
documentation, and didn't seem to care to use the same compiler which is
available in ports, I believe it is safe to chuck this lame benchmark.


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