Tuning FreBSD with specific applications

[Vittorio De Martino]

Alle 22:35, giovedì 02 giugno 2005, Mark Bucciarelli ha scritto:
> On Thu, Jun 02, 2005 at 10:17:13PM +0200, Vittorio De Martino wrote:
> > How could I obtain those improvements? What could I do to speed those
> > programs under freebsd?
>
> - Edit /etc/make.conf and set the processor and compiler optimizations.
>
> - Rebuild and install system (world and kernel)
>
> - Repost your results here. ;)
>
> The BSD handbook has good docs on the last step of this process.  Coming
> from Gentoo, you probably have a good idea what to do in the first step.
>
> There is an example make.conf somewhere on you system you can look at
> for other things to set.
>
> If you want to get really detailed, look at the Makefile for R in it's
> ports directory.  There may be some notes as to configure options and
> performance.
>
> FWIU, every port can have it's own set of configure options, and there
> is a way to put conditionals inside make.conf; for example, if in this
> ports directory, set this option.  I haven't used that yet, but if you
> search the archives here you will find an example.
>
> BTW, don't mess around with the new scheduler.  Just use the old BSD
> one.  I did some testing (recompiled gcc) and the old one was faster on
> a dual processor system.  From what someone told me on #freebsd, it
> works but is not optimized yet.
>
> Also, there are somethings you should do when testing speed.  You can
> google to find the references, here's the two items I remember:
>
> - use single user mode (no cron)
> - unplug network cable (no broadcast packets)
>
>
> Have fun!

Mark, after some other trial I decided in the end to concentrate on an 
application, R, trying to extract the best out of it in term of performance. 
That's why I deinstalled both in gentoo and in freebsd R, downloaded the 
2.0.1 source tarball from the r-project , compiled it in both OSs with the 
same configuration and options.
Now it happens that one test program working only in memory is executed in 
almost the same time in linux and in freebsd (a bit longer under win xp).
Another R test program working mainly in memory but producing a lot of output 
on the screen of the text console, works happily and fast in linux bash 
console whilst in freebsd csh console I see the R program to start happily 
and the output flowing rapidly on the screen, after some time it starts 
slowing down, then clogging. In the end it takes twice as much time to 
complete with respect to gentoo!
Could the difference be the bash in linux and csh in freebsd shell? 
Suggestions?
Vittorio