Intel C2D COREs not used equally in FreeBSD 7.0-CURRENT i386

Abdullah Ibn Hamad Al-Marri almarrie at gmail.com
Wed Jun 6 10:51:18 UTC 2007


On 6/6/07, Dag-Erling Smørgrav <des at des.no> wrote:
> Oliver Fromme <olli at lurza.secnetix.de> writes:
> > It's a common mistake to assume that amd64 only makes sense
> > if you have >= 4GB RAM.  There are several reasons why it
> > might be useful to switch from i386 to amd64:
> >
> >  - Most programs (though not all) will run faster, because
> >    in amd64 mode there are twice as many general-purpose
> >    registers, giving compilers much better opportunities
> >    for optimizations and caching of values, and reducing
> >    slow memory accesses.
>
> "twice as many" is an understatement.  AMD64 has 16 GPRs vs i386's 8 if
> you consider BP, SI, DI and SP as GPRs (as the AMD and Intel literature
> does); in practical terms the score is 12 to 4.
>
> >  - Some applications might benefit from a larger virtual
> >    address space > 4 GB.  (Note that this is not related
> >    to the amount of physical RAM!)
>
> For instance, Varnish maps its entire storage into memory, and will
> benefit greatly from the increased address space.
>
> > In practice there's (almost) only one reason not to run
> > FreeBSD/amd64 on amd64-capable hardware:  If you depend
> > on a certain piece of software which is known not to run
> > correctly in 64bit mode.  Fortunately those are not many.
>
> The only one I can think of (for a desktop) is the Flash plugin.
>
> DES
> --
> Dag-Erling Smørgrav - des at des.no

So switching to AMD64 arch would boot MySQL performance for my case 2
cores and 2 GB of ram?


-- 
Regards,

-Abdullah Ibn Hamad Al-Marri
Arab Portal
http://www.WeArab.Net/


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