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From: "fh_p at hotmail dot com" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/53292] New: multi-threaded (OpenMP) is slower than single-threaded Date: Wed, 09 May 2012 08:18:00 -0000 [thread overview] Message-ID: <bug-53292-4@http.gcc.gnu.org/bugzilla/> (raw) http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53292 Bug #: 53292 Summary: multi-threaded (OpenMP) is slower than single-threaded Classification: Unclassified Product: gcc Version: 4.6.2 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ AssignedTo: unassigned@gcc.gnu.org ReportedBy: fh_p@hotmail.com Created attachment 27352 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=27352 cpp file to compile Hello, The problem is : multi-threaded (OpenMP) is slower than single-threaded Test has been ran several times successively. ChunkSize imposed to avoid false sharing. Test ran on Ubuntu 12.04 64 bits / 4Gb RAM / CPU i3 (dual core hyper-threaded : 2 physical cores + 2 logical cores) / gcc version : 4.6.2. Is the problem related to CPU ? i3 hyper-threaded would not be "handled correctly" by g++ or Ubuntu ? Can somebody help or give me clue ? Thanks, FH PS : I am not used to post bug, if this bug has not been posted in the right place feel free to tell me where to post it
next reply other threads:[~2012-05-09 8:03 UTC|newest] Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top 2012-05-09 8:18 fh_p at hotmail dot com [this message] 2012-05-09 9:23 ` [Bug c++/53292] " fh_p at hotmail dot com 2012-05-09 10:37 ` fh_p at hotmail dot com 2012-05-09 12:20 ` jakub at gcc dot gnu.org 2012-05-09 12:56 ` fh_p at hotmail dot com 2012-05-09 13:00 ` fh_p at hotmail dot com 2012-05-09 13:33 ` jakub at gcc dot gnu.org 2012-05-09 14:48 ` fh_p at hotmail dot com 2012-05-09 15:02 ` jakub at gcc dot gnu.org 2012-05-12 21:35 ` fh_p at hotmail dot com
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