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Any system wide graphite CFLAGs recommendations?
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jasn
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Joined: 05 May 2005
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Location: Maryland, US

PostPosted: Tue Dec 04, 2012 1:54 pm    Post subject: Any system wide graphite CFLAGs recommendations? Reply with quote

I was curious if there's been any consensus on graphite CFLAGs to enable. (I'm running ~amd64 gentoo-sources-3.6.8 with gcc-4.7.2 on my system.) Are;
Code:
-floop-interchange -floop-strip-mine -floop-block -fgraphite-identity

ok to enable system wide? Any pointers to the complete graphite CFLAG documentation would be helpful as well.

Thanks..
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Raeior
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Joined: 17 Jul 2012
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PostPosted: Fri Dec 07, 2012 10:04 am    Post subject: Reply with quote

I'm using "-floop-interchange -floop-strip-mine -floop-block -fgraphite-identity" with GCC-4.7.2 on my laptop (march=corei7, x86-64) and it's working fine most of the time. If it has any impact on performance...no idea but probably nothing significant. But there are still packages in the tree that don't compile (dev-lang/tcl for example, also pyqt4 which hits this bug http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51984) or that exhibit strange runtime failures. For example I couldn't log into my machine using kdm, when compiling qt-core and qt-script with graphite flags enabled, because kinit crashed. Amarok does not start, but i'm not sure if this is related to having graphite enabled on one of it's dependencies. Libreoffice fails some of it's testcases with graphite enabled and icedtea fails bootstrapping if I remember it correctly. Dolphin and kcalc also crashed on exit when compiling qt-gui with graphite.
So this is my list of packages with graphite disabled:

dev-java/icedtea
dev-lang/tcl
dev-python/PyQt4
kde-base/kdelibs
media-sound/amarok
x11-libs/qt-core
x11-libs/qt-script

So basically you have to decide for yourself if it's worth the hassle. Depending on the stuff you have installed you might hit no problems at all, so maybe just try it out. For me it's more of a irrational "hey new stuff" decision, so I still have those flags activated even though there are bugs. All in all this led me to using creduce and trying to work my way through c++ for the first time to create a minimized testcase, which was quite interesting.

On the topic of graphite bugs, should this stuff be reported on the gentoo bugzilla or using (in case of kde bugs) the kde crashreporter? They occur because of unsupported cflags and with the exception of an ICE are harder to minimize and to pinpoint, so i wasn't sure about reporting errors like this.

For documentation you can either use http://gcc.gnu.org/onlinedocs/gcc-4.7.2/gcc/Optimize-Options.html for the meaning of the compiler flags or http://gcc.gnu.org/wiki/Graphite which contains links to the papers and implementation details.

Hope this helps a bit.
Raeior
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mv
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Joined: 20 Apr 2005
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PostPosted: Fri Dec 07, 2012 11:41 am    Post subject: Reply with quote

My list of excluded packages is similar but a bit longer (although I had no difficulties with kdelibs and qt-script so far); I use neither PyQt4 nor amarok.
/etc/portage/package.cflags/graphite wrote:
app-emulation/vice +fgraphite* +floop-*
app-office/libreoffice +fgraphite* +floop-*
dev-java/icedtea* +fgraphite* +floop-*
dev-lang/python +fgraphite* +floop-*
dev-lang/tcl +fgraphite* +floop-*
# This might be needed after an upgrade of dev-libs/ppl, since then gcc cannot use graphite optimizations:
#dev-libs/cloog-ppl +fgraphite* +floop-*
games-emulation/dosbox +fgraphite* +floop-*
games-rpg/freedroidrpg +fgraphite* +floop-*
media-gfx/gimp +fgraphite* +floop-*
media-libs/libcaca +fgraphite* +floop-*
media-sound/audacity +fgraphite* +floop-*
media-sound/timidity++ +fgraphite* +floop-*
sci-mathematics/octave +fgraphite* +floop-*
sys-devel/llvm +fgraphite* +floop-*
sys-fs/encfs +fgraphite* +floop-*
www-client/firefox +fgraphite* +floop-*
x11-libs/qt-core +fgraphite* +floop-*
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jasn
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Joined: 05 May 2005
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Location: Maryland, US

PostPosted: Fri Dec 07, 2012 10:54 pm    Post subject: Reply with quote

Thanks for the replies.

While I was able to actually see some packages which wouldn't emerge while using the graphite CFLAGs, I was unaware of packages that would emerge ok, but then not run correctly, until I read this thread and this bug report, regarding libreoffice. I think for now, I'll just leave them out, until some of these issues are addressed. Also while I admit I like to turn on the new stuff, "just because", I'm not sure what benefit exists for using the graphite CFLAGs today.

Thanks again..
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