------- Comment #4 from hubicka at ucw dot cz 2005-10-28 21:29 ------- Subject: Re: [Bug gcov/profile/24487] [3.4/4.0/4.1 Regression] Basic block frequencies inaccurate
> > > ------- Comment #3 from dje at gcc dot gnu dot org 2005-10-28 17:30 ------- > The misprediction causes (or at least contributes to) compute_alignments in > final.c not aligning the critical loop in longest_match. The recent changes > to > bb-reorder.c moved the start of the loop from an ideal alignment to the worst > alignment, causing a 8-10% performance drop due to instruction fetch > problems. > Without the explicit alignment directives omitted because of misprediction, > the > alignment of the loop is random. I see, Athlon is less sensitive to alignment that might explain it. I will try to fix my SPEC testing setup on PPC after SVN revamp and benchmark it there too... Honza > > > -- > > dje at gcc dot gnu dot org changed: > > What |Removed |Added > ---------------------------------------------------------------------------- > CC| |dberlin at gcc dot gnu dot > | |org > > > http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24487 > > ------- You are receiving this mail because: ------- > You are on the CC list for the bug, or are watching someone who is. > You are the assignee for the bug, or are watching the assignee. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24487
