From: Robert Klemme <bob.news@...>
Date: 2005-06-17T21:40:33+09:00
Subject: Re: Super-scalar Optimizations

Devin Mullins wrote:
> Remembering, vaguely, my comp arch class, I'm pretty sure the
> co-worker (or cow-worker, if you really don't like him) was talking
> not about threading, but about how some VLIW (very long instruction
> word, i.e. not 32-bit) machines include a 'predicate' in addition to
> the instruction (i.e. MOV FOO, BAR IF EQL ALREADY_RUN, 0 is one
> instruction). I presume, then, you guys are not running on x86.
> 
> And no, Ruby's too high level, and yeah, not compiled.
> 
> And wouldn't it be faster still just to pull foo = bar out of the
> while loop? :)

Even more so: what's the point of a loop that is alway run only once?

    robert

> 
> Devin
> 
> Robert Klemme wrote:
> 
>> Phil Tomson wrote:
>> 
>> 
>>> I'll take a stab at this, but I'm no expert....
>>> 
>>> Your cow-worker _may_ be right about the differences between the two
>>> code snippets.  I would think that you'd have to know what kind of
>>> assembly code got generated by the two different snippets, though.
>>> Perhaps he's taken a look at the compiled code.  It also seems like
>>> it could differ a lot between compilers (g++ vs. VC++).
>>> 
>>> As far as Ruby code goes, I don't think you would see any difference
>>> because Ruby doesn't get compiled to native code (yet ;-).  Though
>>> there may be differences in how the interpretter handles the two
>>> different snippets which could possibly effect speed, it would have
>>> nothing to do with anything deep down in the actual hardware
>>> processor.
>>> 
>>> 
>> 
>> .... especially as Ruby does no parallelism internally (no native
>> threads). 
>> 
>> My 0.02EUR...
>> 
>>    robert