i386 vs amd64?

[Oliver Fromme]

Ask Bjørn Hansen <ask at develooper.com> wrote:
 > We got 4 new SuperMicro boxes[1] with Xeon 3320 processors.  They'll  
 > be used as firewalls / very basic routers (our network on one side,  
 > the world via a /29 on the other side).  We currently use Soekris and  
 > PC Engine boxes for this (with custom NanoBSD images), so this will be  
 > a bit of an upgrade.  :-)
 > 
 > I was planning to install pfSense on them, but I'm losing faith in  
 > that a bit after figuring out that the pfSense project doesn't seem  
 > all that open[2]; so I'm considering just installing "plain FreeBSD 7"  
 > instead.
 > 
 > So the question: Would I be happier with 64 or 32bit FreeBSD?   Our  
 > Linux application and database servers are all 64 bit, but they also  
 > have 32GB RAM each.  The "firewall boxes" are probably vastly overdone  
 > with memory at 4GB each.  :-)

There are other reasons to prefer amd64 over i386, beside
the amount of RAM and address space considerations.

For example, in amd64 mode there are twice as many CPU
registers available, enabling better optimizations for
the C compiler.  Furthermore those registers are twice
as long, which means that 64bit quantities can be handled
with single processor instructions.

That doesn't necessarily mean that code will always run
faster in amd64 mode.  There have been reports of certain
edge cases.  But in general, amd64 code is faster.

Also note that the networkign and packetfilter code uses
quite a few 64bit variables (e.g. packet and byte counters).
That's probably not significant for a small router, though.

Bottom line:  Install FreeBSD/amd64, unless you have
_specific_ reasons to stay with i386.

 > A secondary question:  Is the preferred way to upgrade a FreeBSD box  
 > still cd /usr/src; make update && make buildworld && ... ?

Yes, basically.  Please see the section titled "To rebuild
everything" in /usr/src/UPDATING, it lists all the steps
required for an update.

Best regards
   Oliver

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