http://bugzilla.opensuse.org/show_bug.cgi?id=1040589 Bug ID: 1040589 Summary: bash/gcc/gzip/python differ between builds because of profiling Classification: openSUSE Product: openSUSE Tumbleweed Version: Current Hardware: Other OS: openSUSE 13.2 Status: NEW Severity: Normal Priority: P5 - None Component: Basesystem Assignee: rguenther@suse.com Reporter: bwiedemann@suse.com QA Contact: qa-bugs@suse.de CC: matz@suse.com Found By: Development Blocker: --- In https://build.opensuse.org/project/prjconf/openSUSE:Factory we have %do_profiling 1 and because of that in our bash.spec we enable gcc's 'profile feedback directed optimizations' but that causes the jobs.o and resulting bash binary to differ between builds, even when running on the same build host. And because of that, build-compare always thinks there is a change and triggers a re-publish and rebuild of depending packages We also have such binary diffs in gcc6 and gcc6.spec calls a make profiledbootstrap The do_profiling macro is used in bash gzip hello python3-base python-base sed xz and in http://rb.zq1.de/compare.factory-20170523/bash-compare.out http://rb.zq1.de/compare.factory-20170523/gcc6-compare.out http://rb.zq1.de/compare.factory-20170523/gzip-compare.out http://rb.zq1.de/compare.factory-20170523/python-base-compare.out http://rb.zq1.de/compare.factory-20170523/python3-base-compare.out we have strange diffs in assembler that I could not trace down to other sources of non-determinism until today. Diffs did go away when building without profiling (it was harder to disable for gcc6 and bash though) Do the profiles just count invocations of functions or do they depend on the type and speed of the system? In the first case, it should be possible to fix the profiling runs to be deterministic, but for that it would be useful to be able to see the differences between runs. How could I diff gcc's .gcda files? -- You are receiving this mail because: You are on the CC list for the bug.