[OpenIndiana-discuss] 32-bit and/or 64-bit programs (Was: Bash bug issue)

[Bob Friesenhahn]

On Tue, 11 Nov 2014, Bruce Lilly wrote:
>
> ==> time.32.1 <==
>
> real 0.43
> user 0.38
> sys 0.03

Such short run-times are not particularly accurate since times(2) only 
counts time in terms of kernel clock ticks (e.g. 100hz) and other 
factors may also dominate the run times.  Use OpenIndiana/Solaris 
'ptime -m' if you need more precise time accounting than traditional 
'time' can provide.

Here are some simple performance tests of a heavily floating point and 
heavily parallel algorithm with GraphicsMagick (using its built-in 
benchmark driver) compiled as 64-bit and 32-bit using GCC:

64-bit:

gm benchmark -duration 10 convert -size 4000x3000 xc:gray -gaussian 0x3 null:
Results: 32 threads 20 iter 309.75s user 10.45s total 1.914 iter/s 0.065 iter/cpu

32-bit:

gm benchmark -duration 10 convert -size 4000x3000 xc:gray -gaussian 0x3 null:
Results: 32 threads 18 iter 302.67s user 10.29s total 1.749 iter/s 0.059 iter/cpu

The key factors above are the 'iter/s' and 'iter/cpu' values.

In the above cases, the 64-bit version ran a bit faster.

If the amount of data required exceeds what the 32-bit version can 
handle, then the 64-bit version runs a *lot* faster.

Bob
-- 
Bob Friesenhahn
bfriesen at simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/