FreeBSD vs Ubuntu - Discuss...

O. Hartmann ohartman at
Tue Sep 29 19:30:48 UTC 2009

Andrew Kuriger wrote:
> On Mon, 28 Sep 2009 19:26:34 PDT, Dieter <freebsd at>
> wrote:
>> 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.
> ~Andrew

I doubt that debugging switches left in some places a normal admin or
user can't get so easy are the reason why FreeBSD 8.0-RC performs that
bad compared to Ubuntu 9,1-Linux.
The question at this point would be, whether debugging was enabled on
Linux as well or not ...


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