<div dir="ltr">Hi Luboš, Many thanks for your thoughts on the checkbox, which confirms what I expected. As for the processing itself, I remain unclear about how Calc allocates tasks to threads. Can we give the user any general advice on how he could structure his spreadsheet to gain the maximum performance benefits from the availability of multiple cores? Or maybe there are ways to organise a spreadsheet that will frustrate Calc's attempts to multi-thread, which we ought to advise against? Any further help would be greatly appreciated. Regards, Steve</div> <div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Thu, 23 Apr 2020 at 09:58, Luboš Luňák <<a href="mailto:l.lunak@collabora.com">l.lunak@collabora.com</a>> wrote: </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">On Wednesday 22 of April 2020, Olivier Hallot wrote: > Hi Developers > > Can charitable soul involved with threading in Calc spend a couple of > minutes to write an outline of what we should look to write a section on > the topic in our guide and Help? Just the outline and some pointers for > our investigation. > > We think this feature is a plus, but it is not clear if and how an end > user will benefit. The "Enable multi-threaded calculation" checkbox is one of those settings that aren't actually a preference, in an ideal world they should always be enabled, and in fact shouldn't even exist as the thing should Just Work(TM). We have others like that, 'Allow use of OpenCL', 'Use OpenGL/Skia for all rendering', etc. So AFAICT the purpose of those settings is to admit that we don't live in an ideal world and the setting allows people to disable the feature in case it turns out it's buggy (which incidentally is relatively more likely for all the settings I mentioned). So the way I see it the best thing the docs can say about it is something along the lines of "this does roughly that, don't touch it unless you know you want to touch it". ... > One of the issues we chose to ignore in the 6.2 Calc Guide was > multi-threading. The 6.2 Calc Guide contains the following mention of it, > when describing the Tools > Options > LibreOffice Calc > Calculate page: > > CPU threading settings section > Enable multi-threaded calculation controls the use of multi-threading / > parallelism, which can be used to speed up LibreOffice Calc calculations on > computers with multiple processing cores. -- Luboš Luňák <a href="mailto:l.lunak@collabora.com" target="_blank">l.lunak@collabora.com</a> </blockquote></div>