Rohit Garg wrote: > Hi all, > > I have a small app. In it in a a particular place, I had a 2-3 > functions being called from one main function. They were small > functions (5-6 lines) and inline keyword was used. The performance was > ......... HORRIBLE. > > -Winline didn't report any case of a function not being inlined. > > I didn't know where to start. So I manually inlined these functions. > They are very small and quite trivial. The program now shows ~60x > speed-up in that part of the code. I have no idea what's the cause of > this dramatic speed up. But I suspect it is because I am using g++ to > make a shared library. All the functions referred to here are in one > file. It is complied by using a -c -fPIC option to make a .o file. > Several .o files are later packed together into a .so file using a > -shared option. 60x? I wouldn't have thought so. I guess it's possible that inlining reveals things that the optimizer wouldn't otherwise see. I can't understand why the function wasn't inlined either. We'd have to see an example. Andrew.
