[Bug regression/35671] GCC 4.4.x vs. 4.2.x performance regression
--- Comment #10 from jhopper at safe-mail dot net 2009-07-30 04:16 --- abit more comprehensive gcc 4.2.4 vs 4.3.3 vs 4.4.0 vs 4.4.1 comparison using nbench: hardware: Intel celron 320 (prescott, SSE3, 256KB L2, socket 478) @ 2970 mhz kernel: specially optimized by intel compiler 10 (linuxdna) version 2.6.29.1 http://manoa.flnet.org/nbench-celron-results.txt -- jhopper at safe-mail dot net changed: What|Removed |Added CC||jhopper at safe-mail dot net http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35671
[Bug regression/35671] GCC 4.4.x vs. 4.2.x performance regression
--- Comment #11 from jhopper at safe-mail dot net 2009-07-30 04:24 --- forgot to mention executable sizes: all tested gcc versions 4.2 4.3 and 4.4 were 100kb, intel executables were 68 and 72 kb respectively (version 10, 11). executable size in memory (both VIRT and RSS) did not change between versions (the program is very small) -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35671
[Bug regression/35671] GCC 4.4.x vs. 4.2.x performance regression
--- Comment #12 from jhopper at safe-mail dot net 2009-07-30 04:34 --- one more note about executable size in memory: while there was no difference in sizes in memory for all gcc versions for icc versions there was a great difference: VERSION VIRTRSS gcc (all) ~2000kb 500kb icc10 (all) ~5500kb 800kb but that should be obvious due to the additional linking in icc to libimf.so, libintlc.so.5, libsvml.so, libgcc_s.so.1, libpthread.so.0 and libdl.so.2 that can possibly be countered to make a more fair memory usage comparison between icc and gcc by modification to my icc.cfg configuration files, which were when compiling this program: http://manoa.flnet.org/icc10.cfg http://manoa.flnet.org/icc11.cfg -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35671
[Bug regression/35671] GCC 4.4.x vs. 4.2.x performance regression
--- Comment #13 from jhopper at safe-mail dot net 2009-07-30 04:39 --- one last thing: and try not to take the LU DECOMPOSITION test seriously between the various gcc testing runs, there was great difference even when using the same executable several times, except of corse for the huge gap between intel's and gcc's -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35671
[Bug regression/35671] GCC 4.4.x vs. 4.2.x performance regression
--- Comment #14 from jhopper at safe-mail dot net 2009-07-30 05:09 --- one more thing to mention about gcc, is the configurations during their compilation: (although it may not have much sense as those things were never really having an effect to the anticipated extent) ../gcc-4.a.b/configure --prefix=/opt/gcc4ab --libexecdir=/opt/gcc4ab/lib --enable-shared --enable-threads=posix --enable-__cxa_atexit --enable-clocale=gnu --enable-languages=c,c++ --disable-libstdcxx-pch --disable-bootstrap --disable-stage1-languages --disable-objc-gc --disable-libssp --disable-libada --with-gmp=/opt/gmp --with-mpfr=/opt/mpfr --with-ppl=/opt/ppl --with-cloog=/opt/cloog --with-mpc=/opt/mpc just in case there were any hope for cloog and ppl for this program I made sure it was properly included in the compiler, but unfortunately from the tests as you can see, those options had no effect on nbench -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35671
[Bug regression/35671] GCC 4.4.x vs. 4.2.x performance regression
--- Comment #15 from jhopper at safe-mail dot net 2009-07-30 06:37 --- btw, these results also show something else of interest: pgo degrades performance -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35671
[Bug regression/35671] GCC 4.4.x vs. 4.2.x performance regression
--- Comment #17 from jhopper at safe-mail dot net 2009-07-30 23:58 --- you can find a nicer version of results (and potentially future updates) here: http://anonym.to?http://manoa.flnet.org/linux/compilers.html -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35671
