Bug 139355 - Libre Office not using all CPU cores
Summary: Libre Office not using all CPU cores
Alias: None
Product: LibreOffice
Classification: Unclassified
Component: Calc (show other bugs)
(earliest affected) release
Hardware: x86-64 (AMD64) Windows (All)
: medium normal
Assignee: Not Assigned
Depends on:
Blocks: Calc-Threaded
  Show dependency treegraph
Reported: 2021-01-01 13:50 UTC by Mahajan Deepak
Modified: 2022-06-26 03:32 UTC (History)
4 users (show)

See Also:
Crash report or crash signature:


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Description Mahajan Deepak 2021-01-01 13:50:29 UTC
We have tried to work with a formula with large data process.  

While process is going on for more than half an hour, we found that soffice.bin only using 12 to 13% CPU.  Also while we checked CPU core's graph's it shows only 3 cores used out of 8 cores.  We run the process on Intel i7-3770 cpu @3.40 GHz, with 64 bit OS and 8 GB RAM.  Installed software is also 64 bit & Libre Version

Hope this information will help to improve the LibreOffice performance.

Steps to Reproduce:
1. Tried to rerun the software with same query
2. Added CPU priority with High
3. Manually selected CPU affinity, but same core counts used.

Actual Results:
Same as described.

Expected Results:
Need to use all CPU cores for faster performance.

Reproducible: Always

User Profile Reset: No

Additional Info:
Comment 1 raal 2021-01-01 22:41:02 UTC

Thank you for submitting the bug. The bug has previously been reported, so this bug will be added as a duplicate of it. You will automatically be CCed to updates made to the other bug.

*** This bug has been marked as a duplicate of bug 65046 ***
Comment 2 Telesto 2021-01-02 07:43:09 UTC Comment hidden (obsolete)
Comment 3 Mahajan Deepak 2021-01-06 08:50:45 UTC
(In reply to Telesto from comment #2)
> bug 65046 is pretty old.. there is multi thread for calc.. so prefer small
> investigation first
> Is it possible to recreate a dummy testing dataset with the same formula. It
> sounds to me like the formula is causing a fall back to single thread

Thanks Telesto,

Here is the formula we used to test performance:
=INDEX('file:///D:/Main Data Do not Delete/Desktop/ZCA51.xlsx'#$Alt.$A$1:$C$1048576,MATCH(A5,'file:///D:/Main Data Do not Delete/Desktop/ZCA51.xlsx'#$Alt.$B$1:$B$1048576,),3)

If need I could share my screen by remote, so it will help to resolve it better.
Comment 4 QA Administrators 2021-01-07 04:11:22 UTC Comment hidden (obsolete)
Comment 5 Buovjaga 2021-11-26 14:37:57 UTC
Please attach a file for testing and please test with 7.2 or newer.

Change back to UNCONFIRMED after you have provided the document.
Comment 6 QA Administrators 2022-05-26 03:43:36 UTC Comment hidden (obsolete)
Comment 7 QA Administrators 2022-06-26 03:32:13 UTC
Dear Mahajan Deepak,

Please read this message in its entirety before proceeding.

Your bug report is being closed as INSUFFICIENTDATA due to inactivity and
a lack of information which is needed in order to accurately
reproduce and confirm the problem. We encourage you to retest
your bug against the latest release. If the issue is still
present in the latest stable release, we need the following
information (please ignore any that you've already provided):

a) Provide details of your system including your operating
   system and the latest version of LibreOffice that you have
   confirmed the bug to be present

b) Provide easy to reproduce steps – the simpler the better

c) Provide any test case(s) which will help us confirm the problem

d) Provide screenshots of the problem if you think it might help

e) Read all comments and provide any requested information

Once all of this is done, please set the bug back to UNCONFIRMED
and we will attempt to reproduce the issue. Please do not:

a) respond via email 

b) update the version field in the bug or any of the other details
   on the top section of our bug tracker

Warm Regards,
QA Team