Re: Perfomance degradation 9.3 (vs 9.2) for FreeBSD

On Sun, Apr 20, 2014 at 04:07:25PM +0200, Palle Girgensohn wrote:
> 
> >> If mmap needs to perform well in the kernel, I'd like to know of someone with FreeBSD kernel knowledge who is
interestedin working with mmap perfocmance. If mmap is indeed the cuplrit, I've just tested 9.2.8 vs 9.3.4, I nevere
isolatedthe mmap patch, although I believe Francois did just that with similar results.
 
> > 
> > I did test the 9.3 -devel branch before and after the SysV shared memory =>
> > mmap commit. The performance degradation was visible.
> > 
> > I recently ran a few benchmarks of PostgreSQL 9.3 with different operating systems
> > including DragonFly 3.6 and FreeBSD 10. You may be interested in the results:
> > 
> > http://lists.dragonflybsd.org/pipermail/users/2014-March/128216.html
> > 
> 
> Interesting, indeed. The fixes to dragonfly where made quite recently, in 3.2, right?

The most important fixes occured in the 3.1 development version, around
September 2012.

There was definitely more than an isolated patch; the new scheduler was only
part of the performance improvements.
I'm afraid none of the commits would be applicable as-is to FreeBSD 10.x; the
DragonFly kernel is vastly different in locking, threading and VM management.

The FreeBSD folks should know what to do though; I collected performance
counter data during the last benchmark run and sent it to adrian@.
It was also discussed on freebsd-performance; the thread begins here:
http://lists.freebsd.org/pipermail/freebsd-performance/2014-March/004770.html

-- 
Francois Tigeot