[Beowulf] Has anyone actually seen/used a cell system?
Eric W. Biederman
ebiederm at xmission.com
Mon Oct 2 18:35:38 PDT 2006
"Vincent Diepeveen" <diep at xs4all.nl> writes:
> ----- Original Message -----
> From: "Eric W. Biederman" <ebiederm at xmission.com>
> To: "Vincent Diepeveen" <diep at xs4all.nl>
>>> Which is my bottom line point. You'll need 1000 compiler programmers to get
>>> supported well.
>> Well I believe this 1000 compiler programmers number is quite high.
>> Certainly that isn't needed for a simple language like C. One or
>> two man years is sufficient to write a usable and decent optimizing
>> C compiler.
> The crucial word you use is 'decent'. That's open to judgement.
> The only reason some years ago for me to move from DOS to windows, was the hard
> fact that visual c++ generated executables executing time 20% faster than Watcom
> C++ (at the time the fastest DOS compiler) did do.
> If i can program 1 full week very hard and speedup my chessprogram 0.5% by that,
> then i consider that a very good deal.
> If 'decent' in your eyes is a factor 3 slower than the best C compilers, then so
> be it, but no one is going to use that C-compiler in that case.
Not at all. What I mean by decent is a compiler that gets all of the easy
low hanging fruit but doesn't necessarily hit every corner case just so.
So within a factor of 1%-5% on most codes of the best compilers. But
certainly doing poorly on the few codes that totally pound the corner
cases you could have handled better.
Getting a factor of 3 slower then the best C compilers on most codes
is almost impossible. C hardly leaves you that much room to optimize.
You almost have to write a pessimizing compiler to get that.
> For a good support of a compiler you most definitely need thousands of people.
> In case of a console only compiler with support, you'll already pass the 1000
> quite quickly.
If you can come back and tell me how many more compilers you have written
then we can have a reasonable discussion. Since you chosen to argue
with someone was largely agreeing with you, and was simply putting
things into perspective somehow I doubt there is much of any substance
we can exchange.
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