On Sun, Feb 8, 2009 at 12:40 AM, S Page <i...@skierpage.com> wrote: > Tiago Marques wrote: > >> That software is still not compiled for the Geode LX, which further >> > slows it down. > >> As you say, everything uses CPU on the Geode. Things like >> > decompressing can be made, probably, a lot faster just by using compiler > optimizations. Has this been considered in any way for future releases? > >> From my professional experience, compiler optimizations can account >> > for 10-30% (or more) free performance. > > It seems the binaries in the OLPC OS image are just generic 386 arch > binaries. (Is there a way to definitively tell? A build log like < > http://xs-dev.laptop.org/~cscott/xo-1/streams/joyride/latest/devel_jffs2/build.log> > is unclear.)
file doesn't say much, everything I have compiled with -march=i686 still shows up as i386 binary. I don't know of anything that might tell us that. > > > This is the case even in the jffs2 OS images that will never be used on > anything but the stable XO hardware (or in emulation, which AIUI already > requires AMD CPU emulation because of the tuned kernel). > > So every OLPC and activity binary should be compiled with -mtune=geode > (optimized for Geode, but still runs on any i386), and in jffs2 images they > should be compiled with -march=geode (only runs on Geode). ("Should" as in > "I'd like a pink pony too" ;-) .) I've read some reports that indicate that using -mtune should be good enough for added performance, although I mostly compile with -march for my systems. I never bothered to check but I'll run some tests on the XO to see if it's significant and worth the extra effort(if feasible, as you say). > > > I assume this is what GentooXO does, > http://www.gentooxo.org/features.shtml > > https://dev.laptop.org/ticket/118 is the tracking ticket, > http://wiki.laptop.org/go/Geode_optimization_effort the page. Thanks! Best regards, Tiago Marques > > > Thanks for all you do, > -- > =S Page >
_______________________________________________ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel