Performance comparison, ULE vs 4BSD and AMD64 vs i386

[Kenneth Culver]

Quoting David O'Brien <obrien at FreeBSD.org>:

> On Wed, Feb 25, 2004 at 01:50:35PM -0500, Kenneth Culver wrote:
>> Ok well maybe not with amd64, but I thought that when you add registers
>                                      ^^^^^^^
>
> This is the key word here -- "thought".  No one has done any real analsys
> and thus we can't say jack.  While at first thought compiling for a large
> number of GPR's could be more time consuming; I think there are other
> phases of code generation where the process is slower due to lack of a
> large number of GPR's.

Fair enough.

>
>> Like on PowerPC or Alpha or whatever there are a LOT more GPR's than
>> there are on even Athlon64... I guess only having 2x the GPR's doesn't
>> make a whole lot of difference...
>
> PowerPC and Alpha are also RISC and have other scheduling issues for the
> code generator to handle.
>
I knew they were RISC, but I didn't know that there were that many other issues
in addition to just the GPR's, or I thought that the issues stemmed from having
more GPR's. Anyway, Thanks for the info.

Ken