Re: [9fans] Current status of amd64 port?

[Joshua Wood <josh@utopian.net>]

> 64 bits is neither here nor there in a vaccuum.  you want 64 bits if
> a) you need more than 4GB of memory, or
> a) those extra registers and direct vlong really matter for  
> performance.
> otherwise it's just a lot of extra zeros.
> it's kind of silly to run 64-bit linux on a machine with <= 4GB of  
> memory.
>

Some testing we did about a year ago showed that (for us) even the  
extra registers -- I always thought the sweetest-sounding part of the  
deal -- help sometimes, but not always. I ended up thinking it was  
because caches hadn't necessarily grown apace with address space. The  
distance between cpu and main memory seemed to have expanded again...

64 bits was still the simplest path to > 4G memory for those linux  
machines in that situation, but the observation surprised me.

--
Josh