RE: Kernel tweaks on TT030

[David Ross <dross%pobox.com@localhost>]

ping -c 2 localhost works fine, so feel free to go ahead and update the ATARITT 
kernel config.  Thank you!
 
> That should already be happening,Makefile.atari includes
> sys/arch/m68k/Makefile.cmachflags which sets the compile flags
> automatically based on which of M680[2346]0 are defined.
 
Doesn't seem to be happening properly...  I see -m68020, though I also see 
-DM68030.  (At least that's what I remember seeing during the build, if that 
doesn't sound right I can go back and check.)
 
Any thoughts on a good benchmark to use for -O2 vs '-O2 -Os'?

I will try the test kernel below soon.  What do I check to see that wskbd 
attached?  If it's just "does the keyboard work," that should be easy enough.  
=)
 
David Ross
dross%pobox.com@localhost
 

----------------------------------------
> Date: Sat, 21 Nov 2009 11:42:38 +0000
> Subject: Re: Kernel tweaks on TT030
> From: abs%netbsd.org@localhost
> To: dross%pobox.com@localhost
> CC: port-atari%netbsd.org@localhost
>
> 2009/11/20 David Ross :
>>
>>
>> It looks like we don't need "options FPU_EMULATE" in the ATARITT kernel 
>> configuration file.
>> http://mail-index.netbsd.org/port-atari/2000/01/31/0001.html
>>
>> I tried commenting out that option and I now have a smaller kernel. =) It 
>> boots and seems to work. dmesg still says:
>>
>> Atari TT (m68030 CPU/MMU mc68882 FPU)
>>
>> Since no TT030 shipped without an FPU, we should probably make this change 
>> permanently in /usr/src/sys/arch/atari/conf/ATARITT.
>>
>> Questions:
>> - What's something I can try quickly that would exercise the FPU, just to 
>> test?
>
> 'ping -c 2 localhost' should be a good test (it uses floating point
> for its final summary line), though generally *something* will
> coredump during the boot sequence if floating point is broken. If you
> want to confirm I'll update the ATARITT kernel config.
>
>> - Would it also make sense to move kernel compilation from using -m68020 to 
>> -m68030?
>
> That should already be happening,Makefile.atari includes
> sys/arch/m68k/Makefile.cmachflags which sets the compile flags
> automatically based on which of M680[2346]0 are defined.
>
>> - How about moving from -O2 to -O3?
>
> In general the size/speed tradeoffs in -O3 are not worthwhile. They
> are a benefit in some cases, but it really involves testing before
> just turning them on. Actually given the memory constraints of most
> NetBSD/atari machines it might be better to compile '-O2 -Os'
>
>> - Anything else we might be able to tweak for a "free" performance gain?
>
> Well, TANSTAAFL :), but dropping FPU_EMULATE should definitely gain
> memory, and I'd be curious as to some benchmarks for a kernel compiled
> -O2 vs '-O2 -Os' :)
>
> Actually, if you have a moment could you test booting
> http://mono.org/abs/atari/netbsd-tt-wskbd.bz2
> and see if it attaches a wskbd, and does the keyboard still work? :)          
>