Hi, I'm wondering if anybody can help me on why g++-3.3 is about 80% slower than g++-2.95.4 for an I/O intensive program I'm working on. Now, before I go into the details, that's 80% slower with a call to ios::sync_with_stdio(false) inserted already. Without that it was 5 times slower. I'm working on a library for processing binary data. For benchmarking I'm using two programs: One which just reads the data, analyses (decodes) but doesn't do anyting with it. The other program uses the same framework, but dumps all data in a formatted way to cout. Now analysing a file with g++-2.95 takes about 0.506 seconds, dumping it takes 1.94 seconds. When compiling with g++-3.3, analysing the file takes 0.425 seconds but dumping it takes an amazing 3.58 seconds. Compile flags I'm using are g++-2.95 : -O3 -frerun-cse-after-loop -finline-functions g++-3.3 : -O3 -funroll-loops -march=athlon-xp -ftracer The system debian woody (bunk-1 packages for gcc-3.3) on an AtholonXp 2500+, 512 MB RAM. Anybody who can tell me about a magic switch to turn to speed up writing to cout is highly welcome to do so. Best regards, Torsten
