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Re: compile time regressions (was: merging for 3.4)
- From: Neil Booth <neil at daikokuya dot co dot uk>
- To: Benjamin Kosnik <bkoz at redhat dot com>
- Cc: Dan Nicolaescu <dann at ics dot uci dot edu>, pfeifer at dbai dot tuwien dot ac dot at,echristo at redhat dot com, hubicka at ucw dot cz, jbuck at synopsys dot com,dnovillo at redhat dot com, mark at codesourcery dot com,gdr at integrable-solutions dot net, pcarlini at unitus dot it,libstdc++ at gcc dot gnu dot org, gcc at gcc dot gnu dot org
- Date: Tue, 10 Dec 2002 20:33:02 +0000
- Subject: Re: compile time regressions (was: merging for 3.4)
- References: <F65E3CFB-07D4-11D7-A567-00039390D9E0@apple.com> <Pine.BSF.4.50.0212052132140.63645-100000@naos.dbai.tuwien.ac.at> <200212100246.gBA2kujF029585@gremlin.ics.uci.edu> <20021210112458.4f4b10ca.bkoz@redhat.com>
Benjamin Kosnik wrote:-
> > > gcc-3.0.4/bin/g++ 45.45 user
> > > gcc-3.1.1/bin/g++ 57.79 user +27%
> > > gcc-3.2.1/bin/g++ 59.30 user +30%
> > > gcc-current/bin/g++ 72.29 user +59%
>
> These indicate, to me, that the slowdown has nothing to do with
> libstd++-v3. There just weren't substantial changes in the library
> includes to cause this kind of slowdown between 3.0.x and 3.2.x.
>
> It also indicates the PCH will be less and less useful unless the other
> bits are brought back to normal. Depressing.
That's what scares me about PCH - I'm afraid it'll be used as an excuse
not to fix some of the real problems we have, because "we're fast enough
now". I'd rather wait until we have good performance without PCH before
allowing PCH, though I realize that's not gonna fly.
Neil.