Hi Ian, > The profiling information collects execution counts. The size scales > with the number of branches in your program. It does not scale with the > amount of data nor how long the program runs. Thanks a lot for explaining. The results profile-driven optimizations yield are really impressive :) - Clemens 2009/7/24 Ian Lance Taylor <iant@xxxxxxxxxx>: > Clemens Eisserer <linuxhippy@xxxxxxxxx> writes: > >> I've been playing with profile driven optimizations lately and it >> seems to work really well :) >> Even with -mtune=generic I am able to get a 20% time reduction for a >> critical piece of code. >> >> What I wonder however is, how the profiling informations are collected. >> >> E.g. when profiling pixman, I feed about 1Mio trapezoids to it, >> however gcc only collects ~1.5kb profile information for that Object >> file: >>> -rw-rw-r-- 1 ce ce 1784 2009-07-24 15:22 libpixman_1_la-pixman-trap.gcda >> >> It seems irrelevant how much test-data I feed duing the profiling >> stage, it won't grow beyond that 1.7kb. >> >> Any ideas why? > > > Ian >
