bugGNU Octave - Bugs: bug #63939, strange performance of sparse...


bug #63939: strange performance of sparse matrix operations

Submitter:  Andreas Stahel <andreasstahel>
Submitted:  Fri 17 Mar 2023 03:54:25 PM UTC
Category:  Performance Severity:  3 - Normal
Priority:  5 - Normal Item Group:  Performance
Status:  Invalid / Not an Octave Bug Assigned to:  None
Originator Name:  Andreas Stahel Open/Closed:  * Closed
Release:  * 8.1.0 Operating System:  * GNU/Linux
Fixed Release:  None Planned Release:  None
* Mandatory Fields

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Sat 13 May 2023 12:55:56 PM UTC, comment #2: 

No further comments in about two months.
Since there is probably nothing that Octave could to that would impact the performance with hyperthreads, I'm closing as invalid.
It can be re-opened in case Octave could actually do something about that.

Markus Mützel <mmuetzel>
Group administrator
Fri 17 Mar 2023 04:24:03 PM UTC, comment #1: 
Markus Mützel <mmuetzel>
Group administrator
Fri 17 Mar 2023 03:54:25 PM UTC, original submission:  

On a tight loop with sparse matrices
(one matrix*vector, one system solve by \, both with the same matrix)
the results depends in a stange way on value OMP_NUM_THREADS=32
Octave with GUI started.

leads to 25 seconds of wall time

leads to 5 seconds of wall time

CPU: AMD Ryzen 9 3950X 16-Core Processor,
hyperthreading enabled, i.e. the OS sees 32 cores, 64GB RAM
Xubuntu 22.04

The development version and 8.1.0 lead to the same results

Andreas Stahel <andreasstahel>


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Attach Files:

Attached Files
file #54507:  TestSparse.m added by andreasstahel (485B - text/x-objcsrc)


Depends on the following items: None found

Items that depend on this one: None found


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  • -email is unavailable- added by andreasstahel (Submitted the item)

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    Follow 3 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2023-05-13 mmuetzel StatusNone Invalid / Not an Octave Bug
        Open/ClosedOpen Closed
    2023-03-17 andreasstahel Attached File- Added TestSparse.m, #54507

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