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[Bug libstdc++/40852] [parallel-mode] parallel sort run time increases ~10 fold when vector size gets over ~4*10^9
- From: "jaffe at broadinstitute dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 27 Oct 2009 09:45:43 -0000
- Subject: [Bug libstdc++/40852] [parallel-mode] parallel sort run time increases ~10 fold when vector size gets over ~4*10^9
- References: <bug-40852-8473@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #21 from jaffe at broadinstitute dot org 2009-10-27 09:45 -------
Subject: Re: [parallel-mode] parallel sort run time
increases ~10 fold when vector size gets over ~4*10^9
I tested the patch from comment #19, sorting X billion integers on a machine
having
32 processors and 256 GB memory, X = 4, 6, ..., 26. The overall behavior is
very
close to linear. For example, X = 4 took 1.02 minutes, whereas X = 20 took
5.22
minutes. Very nice!
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40852