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From: "bangerth at dealii dot org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/14809] performance depends on allocation methods Date: Thu, 01 Apr 2004 16:00:00 -0000 [thread overview] Message-ID: <20040401155958.12971.qmail@sources.redhat.com> (raw) In-Reply-To: <20040401120607.14809.boeck@fhi-berlin.mpg.de> ------- Additional Comments From bangerth at dealii dot org 2004-04-01 15:59 ------- I can't reproduce this either, but it took me a while until I understood Falk's comment. The point is: you call malloc/new only once, so the run time of these functions must necessarily be negligible and can't account for the 13 second slowdown you observe. So it must be the output of these functions (for example the alignment of the data region returned), which however is not under gcc control. Since none of us can reproduce this, I guess we should close this PR. For the record, here are the results for running the four testcases: g/x> /home/bangerth/bin/gcc-3.4-pre/bin/c++ -O2 a.cc -o a g/x> /home/bangerth/bin/gcc-3.4-pre/bin/c++ -O2 b.cc -o b g/x> /home/bangerth/bin/gcc-3.4-pre/bin/c++ -O2 c.cc -o c g/x> /home/bangerth/bin/gcc-3.4-pre/bin/c++ -O2 d.cc -o d g/x> time ./a ; time ./b ; time ./c ; time ./d 0 real 0m19.101s user 0m18.792s sys 0m0.016s 0 real 0m19.340s user 0m19.092s sys 0m0.019s 0 real 0m19.135s user 0m18.869s sys 0m0.014s 0 [1]+ Done emacs -fn 9x15 b.cc real 0m20.012s user 0m19.669s sys 0m0.164s W. -- What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |RESOLVED Resolution| |INVALID http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14809
next prev parent reply other threads:[~2004-04-01 16:00 UTC|newest] Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top 2004-04-01 12:06 [Bug c++/14809] New: " boeck at fhi-berlin dot mpg dot de 2004-04-01 13:25 ` [Bug c++/14809] " pinskia at gcc dot gnu dot org 2004-04-01 13:27 ` falk at debian dot org 2004-04-01 15:13 ` boeck at sfhingx dot de 2004-04-01 15:34 ` falk at debian dot org 2004-04-01 16:00 ` bangerth at dealii dot org [this message] 2004-05-03 17:26 ` aleks at physik dot tu-berlin dot de 2004-05-03 18:23 ` bangerth at dealii dot org
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