Hi all, Greetings from me! My OS is ArchLinux, and on this Monday, I upgrade gcc from 6.3.1 to 7.1.1 (both packages are released by ArchLinux). But after rebuilding my program, I find the performance downgrades drastically. For single-thread version, the program which is built with "gcc 6.3.1" would use ~85 seconds to process a transaction; while with "7.1.1", it grows to ~115 seconds. For multiple-thread version using OpenMP, the program which is built with "gcc 6.3.1" would use only ~11 seconds to process a transaction; while with "7.1.1", it grows to ~50 seconds. The compile and link flags are " -g -O2 -fopenmp -fprofile-arcs -ftest-coverage -fPIC -std=gnu++11 ". I also download and build gcc 7.1 myself from https://gcc.gnu.org/gcc-7/, the single-thread program can use ~95 seconds, while OpenMP version still consumes ~50 seconds. So compared to program built using gcc 6.3, the performance is very worse. I have checked the release note of gcc (https://gcc.gnu.org/gcc-7/changes.html), but can't find some valuable information. Could anyone give some comments? Thanks very much in advance! Best Regards Nan Xiao
