Prev: Elaboration query
Next: Dhrystone
From: Ada novice on 26 Jul 2010 13:18
On Jul 26, 5:48 pm, sjw <simon.j.wri...(a)mac.com> wrote:

>
> -gnatp to suppress checks. -gnatn is about inlining.

Yes, sorry for the mix up.

YC
From: Colin Paul Gloster on 27 Jul 2010 11:11
On Sat, 24 Jul 2010, Jonathan sent:

|----------------------------------------------------------------------|
|"[..] |
| |
| time ./bench |
| |
|Let's look at the best results first, and compare the |
|'09 and '10 GNAT GPL compilers: |
| |
| 2010 GNAT GPL: |
| gnatmake bench.adb -gnatnp -O2 -march=native -ffast-math -funroll- |
|loops |
| 3.61 seconds |
| |
| 2009 GNAT GPL: |
| gnatmake bench.adb -gnatnp -O2 -march=native -ffast-math -funroll- |
|loops |
| 4.57 seconds |
| |
|This came as a nice surprise to me! |
|We can learn some more about the compiler switches by |
|toggling them. I'll stick to the 2010 GNAT GPL from now on: |
| |
| change -O2 to -O3: |
| (gnatmake bench.adb -gnatnp -O3 -march=native -ffast-math -funroll-|
|loops) |
| running time changes from 3.61 to 3.63 seconds |
| |
| remove -funroll-loops: |
| (gnatmake bench.adb -gnatnp -O2 -march=native -ffast-math) |
| running time changes from 3.61 to 3.66 seconds |
| |
| remove -ffast-math: |
| (gnatmake bench.adb -gnatnp -O2 -march=native) |
| running time changes from 3.61 to 4.35 seconds |
| |
|The -ffast-math had an amazing affect. I've never seen that |
|before ... maybe an interaction with complex number arithmetic. |
| |
|[..]" |
|----------------------------------------------------------------------|

The GNU Compiler Collection's -ffast-math switch used to provide a
significant increase in speed for various frontends excluding GNAT. In
my experience at least, this effect had no special relationship with
complex numbers.
From: Ada novice on 1 Aug 2010 12:39
In this document:

http://www.benchit.org/downloads/documents/comparing_gcc42_gcc43.pdf

some guidelines are given for increased performance. Tow points worthy
to note:

1. The -ftree-vectorize option is now on by default under -O3.
2. Tuning for Intel Core 2 processors is available via -mtune=core2
and -march=core2.

Have anyone tried these options?

YC

First  |  Prev  | 
Pages: 1 2 3 4 5 6 7
Prev: Elaboration query
Next: Dhrystone