How can I make LibreOffice multi-threaded

LibreOffice is very slow. Even a simple operation on my spreadsheet, such as deleting sheets, takes more than 10 minutes of 100% CPU core usage, completely frozen in process. I cannot even do anything to my other opened documents.

However, it only uses one core. Is it possible to make LibreOffice uses another thread on my different documents such that I can work on those when doing time consuming operations in a document?

To resolve this challenge in part, if possible, upgrade to LibreOffice version 6 or 7 or more recent. Which support multi-threaded calculation.

Steps to activate multi-threaded calculation:

  1. Using LibreOffice 6 Calc, navigate to Tools → Options → LibreOffice Calc
  2. Click on Calculate
  3. Under CPU threading settings, check the box next to Enable multi-threaded calculation
  4. Click on OK button

Below is the same answer as above. But with details if you’re interested in those.
Starting with version 6, LibreOffice now support some multi-threads.

There are a number of performance issues with regard to calc, I do not believe that multi-threading is the problem. It would help to give more details of the problem, for example: version of LibO, operating system, size of spreadsheet, type of spreadsheet, is it a normal .ods or some other type like .xls or .xlsx. Has the problem just starting after changing levels of LibO? If it is a large spreadsheet, have you enough memory set? (tools > options >memory) Sometimes there is a problem with anti-aliasing and other graphics settings ( tools >options > view > graphics)

There are a number of questions already about calc performance, and some known bugs. With more details, someone may well be able to help your annoying problem…Peter

They are .ods files which contains tens of thousands of formulae with indirect references where the user can type in the sheet names into a specified cell in order to fetch data from that sheet.

Tens of thousands of formulas using INDIRECT will slow things down, as there are no known cells or ranges that could be listened to for changes each of those formula cells has to be recalculated on every input.

The problem @erAck mentioned is also present in sheets containing lots of formulae calling OFFSET().
The only way I know to go round the problem is to temporarily switch off the AutoCalculate option.

shouldn’t we make @erAck’s and @Lupp’s comment an answer and check it ‘solved’?

I have the same problem,

  • Problem description: Libreoffice uses only one CPU out of many when convert, concat, insert fields in odt documents, I use Unoruntime

  • Installation:
    Libreoffice 4.4

Java version “1.7.0_91” OpenJDK Runtime Environment (IcedTea 2.6.2) (suse-21.2-x86_64) OpenJDK 64-Bit Server VM (build 24.91-b01, mixed mode)

SUSE Linux Enterprise Server 12 SP1 (x86_64)

  • Current behavior:
    it work very slowly, uses one CPU core at 100% percent, and doesn’t use rest CPU cores. This behavior is in linux and windows systems.

  • Expected behavior:
    Libreoffice will use all avalable CPU.

It is the year 2024. And still, the problem remains. And it is not only a problem in Calc but also in Writer. For example, I need to sanitize document for bug submission (QA/Bugzilla/Sanitizing Files Before Submission - The Document Foundation Wiki), and Search & Replace is going on for hours using only one thread from the 16 I have.

We all know the year and many contributors have spent very many hours since you joined the forum 5 years ago and " Read 28m " not contributing anything. …
Pure consumers wanting to just complain about a “product” should use one they paid for.
You may consider to read this note by Paul Lutus. It’s old but still valid to a relevant part.

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Yes, You are 100% right.
Yes, I am a pure consumer, not an LO developer. I can contribute only in translation, what else?
I can contribute/be involved only by submitting bugs and complaining. Tell me, what do You expect from me? To be quiet (noticing bugs, lack of features, performance issues)?
LO is a lot better than MS Office, which I cannot install on Linux.

Your problem is slow performance, not single-threadedness. Users asking for a specific thing like here, instead of really targeting their real problems, show XY problem. We try to fix performance problems, if they are filed as proper bugs (i.e., with a reproducer documents).

Note that you are talking about sanitizing a document, and slow performance of find/replace. Do you use regular expressions? It is possible that you hit some cases of particularly slow regex performance: as they say, “It doesn’t take a particularly long string for the projected running time to exceed the age of the universe”. No multi-threadedness would heal that; you’d likely need to use quantum computing to defeat that.

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