[Bug libstdc++/38875] parallel fill and copy in the parallel version of libstdc++

[Bug libstdc++/38875] parallel fill and copy in the parallel version of libstdc++

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38875

--- Comment #16 from Paolo Carlini <paolo.carlini at oracle dot com> 2011-04-06 22:25:44 UTC ---
Johannes, I lost a bit track of this enhancement PR: what do you think, now
that we are again in Stage 1 in mainline, are there chances we can resolve it
somehow? Is there something I can do to help?

[Bug libstdc++/38875] parallel fill and copy in the parallel version of libstdc++

[singler at gcc dot gnu dot org]

------- Comment #15 from singler at gcc dot gnu dot org  2009-11-20 09:56 -------
There is slowdown, also for large inputs, for the most simple case, namely
filling constant integer values.  If assignment is more expensive, thing will
get better.  Please try with your application.


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singler at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|WAITING                     |ASSIGNED
   Last reconfirmed|2009-01-16 15:51:05         |2009-11-20 09:56:12
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38875

[Bug libstdc++/38875] parallel fill and copy in the parallel version of libstdc++

[singler at gcc dot gnu dot org]

------- Comment #14 from singler at gcc dot gnu dot org  2009-11-20 09:53 -------
Created an attachment (id=19064)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=19064&action=view)
Functional patch for parallel fill and fill_n.


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singler at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
  Attachment #19053|0                           |1
        is obsolete|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38875

[Bug libstdc++/38875] parallel fill and copy in the parallel version of libstdc++

[wuerzner at gmail dot com]

------- Comment #13 from wuerzner at gmail dot com  2009-11-19 15:47 -------
If you have no speedup, do you recognize any loss of speed due to the
parallelization overhead (for small examples)?


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38875

[Bug libstdc++/38875] parallel fill and copy in the parallel version of libstdc++

[singler at gcc dot gnu dot org]

------- Comment #12 from singler at gcc dot gnu dot org  2009-11-19 15:35 -------
Remove old email address.


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singler at gcc dot gnu dot org changed:

           What    |Removed                     |Added
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                 CC|singler at ira dot uka dot  |
                   |de                          |
             Status|ASSIGNED                    |WAITING


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38875

[Bug libstdc++/38875] parallel fill and copy in the parallel version of libstdc++

[singler at gcc dot gnu dot org]

------- Comment #11 from singler at gcc dot gnu dot org  2009-11-19 15:33 -------
Created an attachment (id=19053)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=19053&action=view)
Functional patch for parallel fill and fill_n.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38875

[Bug libstdc++/38875] parallel fill and copy in the parallel version of libstdc++

[singler at gcc dot gnu dot org]

------- Comment #10 from singler at gcc dot gnu dot org  2009-11-19 15:32 -------
The new patch is functional.  However, for simple cases like setting integers,
I have no speedup (yet).


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38875

[Bug libstdc++/38875] parallel fill and copy in the parallel version of libstdc++

[bkoz at gcc dot gnu dot org]

------- Comment #9 from bkoz at gcc dot gnu dot org  2009-11-05 02:52 -------

Yes, of course. Just providing the framework, since that was a bit tricky.

I should add all the steps here to the parallel mode docs to make this less
confusing for people trying to experiment.

best,
benjamin


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38875

[Bug libstdc++/38875] parallel fill and copy in the parallel version of libstdc++

[paolo dot carlini at oracle dot com]

------- Comment #8 from paolo dot carlini at oracle dot com  2009-11-05 02:33 -------
Cool. Now it would be nice to benchmark it a bit, somehow, a version of it with
the actual code not commented out, I mean ;)


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38875

[Bug libstdc++/38875] parallel fill and copy in the parallel version of libstdc++

[bkoz at gcc dot gnu dot org]

------- Comment #7 from bkoz at gcc dot gnu dot org  2009-11-05 02:16 -------

Here's how parallel fill would look, based on Johannes patch.

-benjamin


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38875

[Bug libstdc++/38875] parallel fill and copy in the parallel version of libstdc++

[bkoz at gcc dot gnu dot org]

------- Comment #6 from bkoz at gcc dot gnu dot org  2009-11-05 02:15 -------
Created an attachment (id=18970)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=18970&action=view)
patch for parallel fill and fill_n


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38875

[Bug libstdc++/38875] parallel fill and copy in the parallel version of libstdc++

[singler at gcc dot gnu dot org]

------- Comment #5 from singler at gcc dot gnu dot org  2009-10-20 07:37 -------
I'm investigating the problem.  In the meantime, you might want to "abuse"
std::for_each for this task.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38875

[Bug libstdc++/38875] parallel fill and copy in the parallel version of libstdc++

[wuerzner at gmail dot com]

------- Comment #4 from wuerzner at gmail dot com  2009-10-15 15:46 -------
Hi,

has there been any change on the std::fill policy, yet? If yes, in which
version did you integrate the parallel fill?

Many thanks,
Kay


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38875

[Bug libstdc++/38875] parallel fill and copy in the parallel version of libstdc++

[singler at gcc dot gnu dot org]

------- Comment #3 from singler at gcc dot gnu dot org  2009-03-23 11:00 -------
A parallelized std::copy was also suggested.


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singler at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|parallel fill in the        |parallel fill and copy in
                   |parallel version of         |the parallel version of
                   |libstdc++                   |libstdc++


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38875