Teresa Johnson <tejohn...@google.com> writes: > This patch enables -freorder-blocks-and-partition by default for x86 > at -O2 and up. It is showing some modest gains in cpu2006 performance > with profile feedback and -O2 on an Intel Westmere system. Specifically, > I am seeing consistent improvements in 401.bzip2 (1.5-3%), 483.xalancbmk > (1.5-3%), and 453.povray (2.5-3%), and no apparent regressions.
One thing that worries me is what this will do to profilers. I had to hack some assembler code using out of line sections to able to handle the libunwind based perf dwarf unwinder. My understanding is that these out of line sections can be only described properly in dwarf3, and there's still some dwarf2 based unwinder code around. So this may cause problems with profiling and debugging. It's probably still a good idea, just may need some extra care. -Andi -- a...@linux.intel.com -- Speaking for myself only
