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Re: Just a reminder of serious open 3.3 PRs


Op ma 14-04-2003, om 22:45 schreef Gerald Pfeifer:
> On Sun, 6 Apr 2003, Steven Bosscher wrote:
> > The two three are serious compile time regressions from 3.2 that should
> > be show stoppers for 3.3 according to the GCC release criteria.  .
> >
> > opt/8361	[3.3/3.4 regression] C++ compile-time performance regression
> > This is a 70% slowdown wrt. 3.0.4, and 30% wrt. 3.2.1.  It was blamed
> > on garbage collection and other things, but no real analysis was done
> > for this problem.  The "official" rule from the release criteria
> > states that "A release candidate's compile-time should not exceed
> > GCC 2.95.3 by more than 15% ..."  Here we have two times the maximum
> > slowdown with respect to the latest official release.
> 
> Here is a comparison of how GCC evolved (snapshots around mid of last
> week):
> 
> 		 -O0           -O1    	    -O2	 	 -O3
> GCC 3.0.4       27.95         44.52	   56.57	56.48
> 3.2-branch      29.87 +7%     54.28 +22%   70.95 +25%	75.29 +33%
> 3.3-branch      29.09 +4%     57.11 +30%   78.99 +40%	81.61 +44%
> mainline        27.06         56.09        77.77	82.02
> 
> Here we have +30% when comparing against 3.0.4 for -O1, and +40% for -O2!

Yes -- but what is a bit surprising (at least, to me) is that most of
the slowdown is already introduced at -O1.

What do the time reports tell you, which parts are the biggest losers? 
I assume you left the default GC params in for 3.3 and mainline?

Greetz
Steven



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