[Info-vax] x86-64 data aligment / faulting

[Scott Dorsey]

Bill Gunshannon  <bill.gunshannon at gmail.com> wrote:
>When the Alpha first came out its attackers used to provide
>example code that performed very badly to prove they were
>better.  Wasn't this one of the methods used to write those
>really bad performing programs?  This and forcing repeated
>dumping of the pipelined instructions?

Yes, although has been pointed out, if you have a large enough array and do
random accesses so that a pull from main memory is needed with nearly every
one, you'll find the x86_64 also performs very badly.

But, having a whole lot of cache helps a whole lot at speeding up clean
well-written code with unaligned accesses, as is noted.

Unfortunately the code that people use to demonstrate defects in system
architectures is frequently little different than the code written by
inexperienced programmers.
--scott

-- 
"C'est un Nagra. C'est suisse, et tres, tres precis."