[User 29008]

tslayer, could this be due to this GCC bug:

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36235

[tslayer]

It is possible

Maybe if you upgrade gcc and test we will know for sure right?

[tslayer]

Actually, not sure it is that because the real only change here was the RUNTIME_CPUDETECT.

The -O3 happened anyways.

[User 29008]

Well sorry tslayer, but I am not gonna compile and install a newer gcc version manually. I am afraid that might have more implications on my ubuntu install than I like :-)
Anyway ... I guess we can tell pretty exactly where the change occured. 15516 works, 15517 does not. Sounds pretty clear to me. Whatever the exact reason now is, it is between those 2 revisions.

boba

[tslayer]

Yep... Agreed.

Guessing it must be the RUNTIME_CPUDETECT.

[User 29008]

What I am trying right now is to compile with O2 instead of O3 opt level. See if that makes any difference.

boba

[tslayer]

Try instead without the RUNTIME_CPUDETECT. Keep everything else.

[User 29008]

ok, next build will be that way, my O2 build is almost done ....

[User 29008]

That's it tslayer. RUNTIME_CPUDETECT. Took it out of configure and voila, 15517 works like a charm with sw upscale enabled :-)
Will now do a clean svn from today with RUNTIME_CPUDETECT taken out.
Thanks for your help ... will that option be taken out of svn then?

boba

[tslayer]

Not sure.. it will need a discussion with the team

[tails_naf@yahoo]

Guys, this was excellent detective work. I am impressed by the dedication involved in narrowing it down.

I will give the gcc flag a try too (hopefully soon), and report back.

Just so I'm clear - what change must be made to what file, for this to work?

Are there other ways to optimize the build with gcc flags? I'm no 32 bit ubuntu, with an intel core 2 quad ..(Q6600)

Cheers,
John

[User 29008]

After SVN checkout modify the files

configure and configure.in

in your XBMC root directory.

Look for the line containing

--extra-cflags="-DRUNTIME_CPUDETECT -O3"

and remove -DRUNTIME_CPUDETECT so that there's just -O3 left between the quotes.

boba

[tslayer]

It's in SVN already. Just svn up.

[tails_naf@yahoo]

It seem the svn version has dropped the -O3 part also - is that supposed to be the case, it seems at odds with what bobba was saying...

[tails_naf@yahoo]

On the topic of optimizations....
I was recompiling and I saw that different -Ox options are used for different modules, for example, ffmpeg seems to be using -o0 ... Surely O3 would be better?

Before recompiling I did:
make clean
edit configure/configure.in as above (left -O3 in there)
./configure
make

So would you expect ffmpeg to have used o0 ?

Cheers
John