Is 6.x slower then 4.x ... ?

Brooks Davis brooks at
Mon Jul 17 03:03:01 UTC 2006

On Sun, Jul 16, 2006 at 11:49:35AM -0300, User Freebsd wrote:
> I've read/seen reports on -questions about this ... especially in an SMP 
> environment ...
> Is there any truth to this?
> One person that posted on -questions pointed out that when he tried to 
> point out the difference, he was told one of:
> >a. It is either your hardware sucks
> >b. your benchmark application sucks
> Now, I don't hold with the 'your hardware sucks' response, as long as one 
> is testing on the same hardware, the hardware itself should affect the 
> results between releases ...
> But, is there any "officially recognized set of tests" that one can use 
> that ppl here accept to negate the chances of b?
> Finally, has anyone here done a set of 'accepted tests' and built up a 
> report that could be linked to from the main page to refute (or 
> vindicate?) the claims that the newer releases are getting slower?

FreeBSD 6 is slower than 4 for some things and faster for others.  That
should be expected since fine grained locking involves increased numbers
of expensive atomic operations (which are particularly bad on Intel
P4 and Xeon systems).  The gain is that we've got significantly more
parallelism in many areas (for example, see kris's I/O benchmarking
presented at BSDCan).  Looking at it as a thought experiment, you should
expect microbenchmarks to perform worse, sometimes much worse.  If
your application looks like those microbenchmarks that's going to be a
problem, if not it may or may not be.

In short the black and white question you are asking makes little
sense. :)

-- Brooks
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