FreeBSD beginner (NetBSD advanced)

[Chuck Swiger]

Wojciech Puchar wrote:
> i installed FreeBSD once to do quick performance tests, and at least in 
> disk I/O and fair scheduling it's MUCH better (tested 4.10 and 5.1).

It's nice to be welcomed by higher performance when you switch OSes.  :-)

> my questions:
> 
> 1) what is Buf and Cache in top exactly? why buf on 96MB machine gets to 
> near 20MB and never goes down? it's almost 1/4 of memory size.

Cache: number of pages used for VM-level disk caching
Buf:   number of pages used for BIO-level disk caching

> 2) can i compile kernel with -march=pentium,pentium[234] -O2 optimization?
> in NetBSD 2.0 doing -march=pentium produces kernel that doesn't boot at 
> all, just resets.

If you want to tune your system, tweaking the options from GENERIC by removing 
at least:

cpu             I386_CPU
cpu             I486_CPU

...will probably result in the greatest improvement, along with disabling 
WITNESS and such if using -CURRENT.  See "man tuning".

Using -march=pentium is likely to be worthwhile (assuming you don't have a 386 
:-), higher than that may run into problems.  Higher optimizations than -O are 
not supported, although work is underway to fix the remaining code issues 
(mainly in libalias used by NAT), as I understand.

If you want to try -O2, give it a shot, but you might consider using either 
"-Os" rather than "-O2", or try "-O2 -fno-strict-aliasing".

> 3) how can i disable compiling, using etc.. all that LKM (KLD) stuff?
> 
> i really prefer one static kernel.

Read the handbook on building the kernel.

> 4) is IPv6 working well? (i mean no crashes etc...) i will get real IPv6 
> zone allocation soon and want to use it.

IPv6 seems to work well, yes.

> 5) what is used in FreeBSD for traffic management. NetBSD has altq - 
> please just give me a name i will RTFM.

If you want to use that, ipf/altq should be available in -CURRENT.  Otherwise, 
ipfw & dummynet is another choice.

> 6) how to turn using serial port as console on i386? my home machine is 
> headless, i'm using X terminals to access it.

See the handbook.

> 7) does FreeBSD support 2 CPUs on i386?

Sure.  See the SMP section of the kernel config file.

> should i go to 4.10 or better 5.2.1? stability is really important to me.

4.10, unless there's a feature from -CURRENT that you don't want to live without.

-- 
-Chuck