We accidentally discovered that our C++ code runs slow when compiled with the 7.1 compiler (as compared to the 5.0 compiler). I was using staticly-compiled binaries for all tests. Here are some numbers:
Compiled under RH7.2 with 5.0.1 compiler:
262.650u 0.310s 4:22.97 99.9% 0+0k 0+0io 48pf+0w
Compiled under RH9 (glibc-2.2.93) with 7.1 compiler:
304.980u 0.400s 5:05.50 99.9% 0+0k 0+0io 53pf+0w
Compiled under RH9 (glibc-2.3.2) with 7.1 compiler:
304.230u 0.430s 5:04.68 99.9% 0+0k 0+0io 53pf+0w
So the new compiler produces binaries that run 10-20% *slower* than the old compiler. What gives? Has anyone else seen this?
By the way, the binaries are always beating gcc. I can probably provice source if needed (have to check with the users first).