Phoronix Benchmarks: Waht's wrong with FreeBSD 8.0?

Ivan Voras ivoras at
Mon Nov 30 13:24:04 UTC 2009

Thomas Backman wrote:
> On Nov 30, 2009, at 9:47 AM, O. Hartmann wrote:
>> I'm just wondering what's wrong with FreeBSD 8.0/amd64 when I read the Benchmarks on's website. Especially FreeBSD's threaded I/O shows in contrast to all claims that have been to be improoved the opposite.
> Corrected link:
> And yeah, quite honestly: disk scheduling in FreeBSD appears to suck... The only reason I'm not switching from Linux. :(

About the only useful result of the "Phoronix benchmark suite" in 
general is that benchmarking is hard, and that though tedious, 
statistical analisys and multiple runs actually have a realistic 
purpose. I suspect their runs have a very large variance between tests 
and are only useful in "order-of-magnitude" sort of comparisons.

Most of their CPU-bound benchmarks therefore show results with 
insignificant differences, and most of the others benchmark the 
compilers. On the other hand, disk IO benchmarks like 
reflect the real state of the things, which can be easily demonstrated 
by a large number of other benchmarks (e.g. blogbench). AFAIK there is 
some speculation among developers about why is this so, but nothing 
definite yet.

For what it's worth, ZFS effectively does a fair bit of its own IO 
scheduling, so persons interested in this particular aspect should also 
try the tests with ZFS. My own tests (with other benchmarks) show that 
ZFS helps significantly, though the cumulative result is still 
significantly worse than Linux's.

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