pgo

I have a system (Linux & C++) doing intensive signal/image processing operations. I would like to use PGO to improve performance of our application. Are there any risks / potential issues I should be aware of when using PGO ? Are unit tests + E2E tests enough to verify that PGO didn't break anything ? Microsoft has system that is modifying conditional jumps based on the usage statistics plus it condenses frequently used pieces of code into smaller number of pages. This essentially compacts effective memory footprint several times and reduces CPU consumption for 20-50%. This system was

Which information does GCC collect when I enable -fprofile-generate and which optimization does in fact uses the collected information (when setting the -fprofile-use flag) ? I need citations here. I've searched for a while but didn't found anything documented. Information regarding link-time optimization (LTO) would be a plus! =D -fprofile-generate enables -fprofile-arcs , -fprofile-values and -fvpt . -fprofile-use enables -fbranch-probabilities , -fvpt , -funroll-loops , -fpeel-loops and -ftracer Source: http://gcc.gnu.org/onlinedocs/gcc-4.7.2/gcc/Optimize-Options.html#Optimize-Options PS.