[opensuse-packaging] Re: [opensuse] installing optimized packages like Gentoo
On 02/10/11 14:37, Carlos Alberto Gueto Tettay wrote:
Hi everybody,
Gentoo linux is an special distro that can be automatically optimized and it offers an extreme performance according to machine specifications.
There is no such magical thing, although some very specific programs like multimedia libraries may run faster with -O3 (and the newer -Ofast) other programs do in fact run slower or produce huge bloated binaries, other optimizations are unsafe and produce broken code. In case you want to help to make binaries faster, the road ahead is awfully complicated, but Im gonna give you some hints on what to look for to start - There are many packages that for historical reasons or old bugs are built with -fno-strict-aliasing, it is needed that someone looks into them to see if such flag is really needed nowdays. - There are other packages that are compiled with less than standard optimization due to old bugs in the compiler, those need to be verified as well. - If you want faster application load times, there are a _lot_ of C and C++ libraries that may be able to load faster if someone takes the time to add "visibility" support to them see: http://gcc.gnu.org/wiki/Visibility for C++ libraries, you might just pass -fvisibility-inlines-hidden to the compiler and then test its functionality. - If you have debugging skills, you can profile particular software in order to find bottlenecks, this particular task is very hard and sometimes require profound knowledge of the language being used as well of the compiler/interpreter/OS. good luck :-D Cheers. -- To unsubscribe, e-mail: opensuse-packaging+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-packaging+owner@opensuse.org
At Wed, 12 Oct 2011 21:40:00 -0300, Cristian Rodríguez wrote:
On 02/10/11 14:37, Carlos Alberto Gueto Tettay wrote:
Hi everybody,
Gentoo linux is an special distro that can be automatically optimized and it offers an extreme performance according to machine specifications.
There is no such magical thing, although some very specific programs like multimedia libraries may run faster with -O3 (and the newer -Ofast) other programs do in fact run slower or produce huge bloated binaries, other optimizations are unsafe and produce broken code.
The architecture option might be a great performance improvement in some cases, especially when SIMD is effective. If it's a library, the architecture-optimized version can be placed additionally in the sub-directory of HWCAP, such as /usr/lib/sse3/. Then ld.so will pick up automatically per running hwcap. So, in theory, we can provide the multiple binaries per arch-optimization base in a single package. But I don't know whether this would be so big gain. There are cases that the arch-optimization really slows down, too. Takashi -- To unsubscribe, e-mail: opensuse-packaging+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-packaging+owner@opensuse.org
On 13/10/11 02:52, Takashi Iwai wrote:
At Wed, 12 Oct 2011 21:40:00 -0300, Cristian Rodríguez wrote:
On 02/10/11 14:37, Carlos Alberto Gueto Tettay wrote:
Hi everybody,
Gentoo linux is an special distro that can be automatically optimized and it offers an extreme performance according to machine specifications.
There is no such magical thing, although some very specific programs like multimedia libraries may run faster with -O3 (and the newer -Ofast) other programs do in fact run slower or produce huge bloated binaries, other optimizations are unsafe and produce broken code.
The architecture option might be a great performance improvement in some cases, especially when SIMD is effective.
If it's a library, the architecture-optimized version can be placed additionally in the sub-directory of HWCAP, such as /usr/lib/sse3/. Then ld.so will pick up automatically per running hwcap.
Yeah that's one option, the other is using ifunc and/or gcc attribute target... That HWCAP thing may be interesting for some selected libraries, do you know where is the FM ? have found no manpage and no authoritative information out there.. :( -- To unsubscribe, e-mail: opensuse-packaging+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-packaging+owner@opensuse.org
At Thu, 13 Oct 2011 13:59:55 -0300, Cristian Rodríguez wrote:
On 13/10/11 02:52, Takashi Iwai wrote:
At Wed, 12 Oct 2011 21:40:00 -0300, Cristian Rodríguez wrote:
On 02/10/11 14:37, Carlos Alberto Gueto Tettay wrote:
Hi everybody,
Gentoo linux is an special distro that can be automatically optimized and it offers an extreme performance according to machine specifications.
There is no such magical thing, although some very specific programs like multimedia libraries may run faster with -O3 (and the newer -Ofast) other programs do in fact run slower or produce huge bloated binaries, other optimizations are unsafe and produce broken code.
The architecture option might be a great performance improvement in some cases, especially when SIMD is effective.
If it's a library, the architecture-optimized version can be placed additionally in the sub-directory of HWCAP, such as /usr/lib/sse3/. Then ld.so will pick up automatically per running hwcap.
Yeah that's one option, the other is using ifunc and/or gcc attribute target...
That HWCAP thing may be interesting for some selected libraries, do you know where is the FM ? have found no manpage and no authoritative information out there.. :(
Sorry, I also have no good info source. I've read it a couple of years ago in some book. But this implies that the method is hackish ;) Takashi -- To unsubscribe, e-mail: opensuse-packaging+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-packaging+owner@opensuse.org
participants (2)
-
Cristian Rodríguez -
Takashi Iwai