From: Dale Stanbrough <dale@cs.rmit.edu.au>
Subject: Re: Stack based allocation vs. Dynamic allocation
Date: 2000/05/31
Date: 2000-05-31T00:00:00+00:00 [thread overview]
Message-ID: <dale-B8D55E.22230631052000@news.rmit.edu.au> (raw)
In-Reply-To: m33dmz9otb.fsf@ns49.infomatch.bc.ca
Ray Blaak wrote:
> Well the code you posted has the heap version working with much smaller
> arrays
> (500 vs 1 million), so of course it will be faster.
>
> Fix the Heap version to have the same array type as in the Stack version
> and try again. I am interested in the answer.
Well Ray was very correct, and i was very wrong! I must apologise for
submitting such obviously bad code.
I've fixed the code, and added in a few extras. I have compared various
variations of the code (in C and in Ada), the results follow...
Ada Stack -- allocating fixed size array
real 17.5
user 16.5
sys 0.0
C Stack -- allocating fixed size array
real 17.0
user 16.2
sys 0.0
Ada Heap -- allocating fixed size array
real 20.3
user 18.8
sys 0.0
C Heap -- allocating fixed size array
real 30.6
user 28.1
sys 0.0
Ada Heap Unconstrained -- allocating fixed sized unconstrained array
real 35.4
user 34.1
sys 0.0
Ada Heap Unconstrained Changing
-- alternating b/w allocating 1E6/3, 1E6 *3 size arrays
real 56.0
user 52.3
sys 0.1
Ada Stack Unconstrained Changing
-- alternating b/w allocating 1E6/3, 1E6 *3 size arrays
real 28.2
user 26.3
sys 0.1
All compiled with gnat 3.12/gcc, on Solaris
Not quite sure why the unconstrained version should be so much more
expensive. Interesting to note of course that the Ada heap version
is -so- much cheaper than the C version. Presumably they are calling
different allocators.
Dale
next prev parent reply other threads:[~2000-05-31 0:00 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2000-05-31 0:00 Stack based allocation vs. Dynamic allocation dale
2000-05-31 0:00 ` Aaro Koskinen
2000-05-31 0:00 ` Ray Blaak
2000-05-31 0:00 ` Dale Stanbrough [this message]
2000-05-31 0:00 ` Laurent Guerby
2000-06-01 0:00 ` Matthew Woodcraft
2000-06-01 0:00 ` Laurent Guerby
2000-06-05 0:00 ` Robert Dewar
2000-05-31 0:00 ` Gisle S�lensminde
2000-05-31 0:00 ` Aaro Koskinen
2000-05-31 0:00 ` Lutz Donnerhacke
2000-05-31 0:00 ` Gisle S�lensminde
2000-05-31 0:00 ` Jean-Pierre Rosen
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