------- Comment #22 from uros at kss-loka dot si 2006-06-27 05:49 ------- (In reply to comment #21)
> Note that you are running the opposite of my test case: SSE vs SSE rather than > x87 vs x87. This whole bug report is about x87 performance. You can get more > detail on why I want x87 in my messages above, particularly comment #11, but > single precision is indeed the place where SSE cannot compete with the x87 > unit. To see it, put the flags back the way I had them in the attachment, and > you'll see that gcc 3 is much faster. Also, you should find in single Hm, these are x87 results: /usr/local.uros/gcc34/bin/gcc -DREPS=1000 -fomit-frame-pointer -O -DTYPE=float -c mmbench.c /usr/local.uros/gcc34/bin/gcc -DREPS=1000 -fomit-frame-pointer -O -c sgemm_atlas.c /usr/local.uros/gcc34/bin/gcc -DREPS=1000 -fomit-frame-pointer -O -o xsmm_gcc mmbench.o sgemm_atlas.o rm -f *.o /usr/local.uros/bin/gcc -DREPS=1000 -fomit-frame-pointer -O -DTYPE=float -c mmbench.c /usr/local.uros/bin/gcc -DREPS=1000 -fomit-frame-pointer -O -c sgemm_atlas.c /usr/local.uros/bin/gcc -DREPS=1000 -fomit-frame-pointer -O -o xsmm_gc4 mmbench.o sgemm_atlas.o rm -f *.o echo "GCC 3.x single performance:" GCC 3.x single performance: ./xsmm_gcc ALGORITHM NB REPS TIME MFLOPS ========= ===== ===== ========== ========== atlasmm 60 1000 0.141 3072.00 echo "GCC 4.x single performance:" GCC 4.x single performance: ./xsmm_gc4 ALGORITHM NB REPS TIME MFLOPS ========= ===== ===== ========== ========== atlasmm 60 1000 0.143 3029.92 -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27827
