[Gllug] Fileserver hardware advice

Nix nix at esperi.org.uk
Fri Mar 23 16:52:47 UTC 2007


On 20 Mar 2007, Tethys spake thusly:

>
> "Martin A. Brooks" writes:
>
>>Where does this myth about 64 bit processing being "slow" come from?
>
> Mostly from sparc64, where it's not a myth.

And MIPS, and basically, oh, every other 32/64 system other than x86-64.

>                                             That's why Linux on sparc64
> (and IIRC, Solaris too) uses a 32-bit userland[1], even when running
> with a 64-bit kernel. Certain key apps will be 64-bit (e.g., databases,

And Emacs :)

> and other apps that need access to large amounts of memory), but the
> rest of the system is 32-bit, IIRC mostly to reduce cache pressure.

Yeah. There's a 5--10% slowdown from 64-bitting a randomly-selected
computationally-intensive app not requiring large pointers (rough
numbers from some Octave runs).

> [1] Disclaimer: I've been out of the loop in the SPARC world for a
>     couple of years, so this might have changed by now.

It hasn't, as far as I know.

-- 
`In the future, company names will be a 32-character hex string.'
  --- Bruce Schneier on the shortage of company names
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