------- Comment #5 from roebel at ircam dot fr 2006-03-22 11:13 ------- Created an attachment (id=11090) --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=11090&action=view) Results file for testcase
As you requested I provide a testcase. It consists of 2 shell scripts that run the different compilers and then run the testcase. The testcase has two cases and two compilation modes: switch 1 compiled with -DHAND it gives hand optimized pointer only version compiled with -DMATMTL it gives the equivalent expression templates version switch 2 compiled with -DBENCH=1 it calculates an addition of three vectors compiled with -DBENCH=2 it calculates an addition of three vectors with some scalar multiplications The name of the excutable will indicate the experiment by two final characters H1 stands for hand optimized first benchmark, M2 stands for matmtl second benchmark ... The two scripts comp.sh and master.sh run the whole experiment: comp.sh runs the experiment for a single compiler and a user supplied set of vector sizes. Note, that each experiment always uses 100000000 vector element operations. By means of the vector size the amount of overhead can be controlled. master.sh runs comp.sh with a single compiler and the vector size arguments 5 and 1000 Results are produced with ./master.sh 2>&1 | tee mout egrep "#|user" mout First result is that gcc 4.1.0 with --param salias-max-implicit-fields=50 is a real success. As you see the compile time does not change "at least for this testcase" but the performance is identical to the pointer only case!!!!!!!!!!!!!!!!!!!! second result is that for gcc 4.1.0 with default parameter set we get performance worse then gcc 4.0.2 especially for small vectors (large overhead). The larger the vectors become the more gcc 4.1.0 approaches 4.0.2 ############################################################### # g++ 4.0.2 the reference ################################################### #compile times user 0m0.702s user 0m0.697s user 0m1.066s user 0m1.077s #run times : vector size 5 # benchmarkredH1 user 0m0.295s # benchmarkredM1 user 0m0.307s # benchmarkredH2 user 0m0.381s # benchmarkredM2 user 0m0.412s #run times : vector size 1000 # benchmarkredH1 user 0m0.230s # benchmarkredM1 user 0m0.243s # benchmarkredH2 user 0m0.287s # benchmarkredM2 user 0m0.370s # g++ 4.1.0 default ################################################### #compile times user 0m0.747s user 0m0.752s user 0m1.211s user 0m1.227s #run times : vector size 5 # benchmarkredH1 user 0m0.264s # benchmarkredM1 user 0m0.519s # benchmarkredH2 user 0m0.347s # benchmarkredM2 user 0m1.211s #run times : vector size 1000 # benchmarkredH1 user 0m0.222s # benchmarkredM1 user 0m0.286s # benchmarkredH2 user 0m0.298s # benchmarkredM2 user 0m0.375s # g++ 4.1.0 salias=50 ################################################### #compile times user 0m0.753s user 0m0.741s user 0m1.225s user 0m1.239s #run times : vector size 5 # benchmarkredH1 user 0m0.262s # benchmarkredM1 user 0m0.307s # benchmarkredH2 user 0m0.344s # benchmarkredM2 user 0m0.313s #run times : vector size 1000 # benchmarkredH1 user 0m0.223s # benchmarkredM1 user 0m0.234s # benchmarkredH2 user 0m0.299s # benchmarkredM2 user 0m0.260s -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26788
