[rescue] Ultra1 OBP firmware message on installation boot

[Sid Odgers]

Yea,

In terms of performance, unless you're doing heavily memory bound
jobs (ie processes which require more than 4GB of VM) or compute
jobs which use 64 bit integers or floats, you'd be hard pressed
to notice the difference.  If you ARE, then 64 bit computation
will be orders of magnitude faster (1 64-bit instruction takes
the place of 3 or 4 32-bit instructions which emulate the
64-bit instructions for long double(?) and long long types),
and large datasets will be unusable as a 64-bit memory pointer
is required to use more than 4GB of VM on flat architectures (
and it's usually not worth the performance hit on segmented
architectures like the newer IA32 stuff which, from memory,
has a 4 bit segment offset pointer in the LDT, allowing you
to address more than 4GB of VM in 4GB chunks)

Nonetheless, 64-bit mode is 'cooler', and the (minimal) performance
hit you take for running 64 bit code instead of 32 bit code isn't
going to be noticable either way on a 1/170. :)

On Thu, Feb 13, 2003 at 02:25:53AM -0500, Patrick Giagnocavo +1.717.201.3366 wrote:
> I am loading Solaris 9 on an Ultra1/170 with OBP 3.5 .
> 
> On boot, the installer gives a message about using the 32bit OS
> instead of 64bit OS.
> 
> I googled and found out how to change it, but my question is, is there
> a performance difference between the 2 kernels?  
> 
> I will be doing some PostgreSQL and web serving and some Perl (spit).
> 
> --Patrick
> _______________________________________________
> rescue list - http://www.sunhelp.org/mailman/listinfo/rescue