Difference between revisions of "Fs2 open on Linux/Optimization"

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(The error from -ftree-vectorize was worked around in r9480)
 
Line 12: Line 12:
 
If you want to play it safe, a good set of CFLAGS would be
 
If you want to play it safe, a good set of CFLAGS would be
 
  $ ./configure CFLAGS="-march=native -O3 -pipe -fomit-frame-pointer -fno-ident" CXXFLAGS="$CFLAGS"
 
  $ ./configure CFLAGS="-march=native -O3 -pipe -fomit-frame-pointer -fno-ident" CXXFLAGS="$CFLAGS"
 
Note: it seems that in GCC 4.7.0 (and higher until at least 4.7.2) the -ftree-vectorize flag (part of -O3) causes segfaults in FSO.  Therefore you could instead use:
 
$ ./configure CFLAGS="-march=native -O3 -pipe -fomit-frame-pointer -fno-ident -fno-tree-vectorize" CXXFLAGS="$CFLAGS"
 
  
 
In particular, the following flag has been reported to increase the FPS when not looking at nebula: (thanks to oldlaptop for this advice)
 
In particular, the following flag has been reported to increase the FPS when not looking at nebula: (thanks to oldlaptop for this advice)

Latest revision as of 09:30, 25 September 2013

« Pre-Compile Configuration The fs2_open on Linux Guide
Optimization
Compiling »

Warning: If you compile a debug build, don't use the -fomit-frame-pointer and -fno-ident compiler flags, as it will make debugging impossible.

Note: This step is only for those who want the bleeding-edge source code to compile on their own. You can skip this if you intend to use a provided binary executable.

Optimizing fs2_open might have little or no effect, or improve performance greatly, I honestly have no clue.
You can specify your compiler flags with the configure script, see below.

$ ./configure CFLAGS="<your desired flags>"

If you want to play it safe, a good set of CFLAGS would be

$ ./configure CFLAGS="-march=native -O3 -pipe -fomit-frame-pointer -fno-ident" CXXFLAGS="$CFLAGS"

In particular, the following flag has been reported to increase the FPS when not looking at nebula: (thanks to oldlaptop for this advice)

$ -fpredictive-commoning

You should read up on CFLAGS and what they do before trying anything. I recommend you read through these links (adjust the URL as required for your version of GCC).
http://gcc.gnu.org/onlinedocs/gcc-4.2.0/gcc/Optimize-Options.html
http://gentoo-wiki.com/Safe_Cflags