To follow up on that. Using LO 6.4 & 7.0 pre-release build on Ubuntu. Recalculating one of the OpenCL test xls files just now.
Starting up with a command line MAX_CONCURRENCY=0 ./soffice Does turn the CPU threading off. Restarting with a command line MAX_CONCURRENCY=4 ./soffice Turns it back on (for my AMD a5800 processor this will give me two threads, because while the CPU is called a 4 core processor and it does have 4 accumulators it only has 2 floatingpoint cores and this is the limiting factor it seems) with recalculation time for the workbook is ~2x faster. On Thu, Apr 23, 2020 at 1:48 PM Drew Jensen <drewjensen.in...@gmail.com> wrote: > BTW I'm copying a paragraph from an email on a different list. > > "Also - if you set MAX_CONCURRENCY=16 - or somesuch (ie. twice your > number of threads) - you may be able to defeat the hyper-threaded > halving, and see if this workload happens to be one that does better > with hyper-threading than without."M.M. > > It might be worth mentioning the MAX_CURRENCY setting for controlling CPU > thread usage. > > Also, I wonder if the folks answering could answer one other question: > Does LibreOffice OnLine also use cpu threading in the same way it does > when run for desktop or headless? It would be with noting in the > documentation if it does not, IMO. > > > > On Thu, Apr 23, 2020 at 9:56 AM Stephen Fanning < > stevemfanning...@gmail.com> wrote: > >> Mike and Luboš, >> >> Many thanks for your help on this topic. >> >> Regards, >> >> Steve >> >> On Thu, 23 Apr 2020 at 11:16, Mike Kaganski <mikekagan...@hotmail.com> >> wrote: >> >>> On 23.04.2020 13:12, Luboš Luňák wrote: >>> > On Thursday 23 of April 2020, Stephen Fanning wrote: >>> >> 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? >>> > >>> > Technically threads are generally used only for formula groups, which >>> are a >>> > sufficient number of adjacent cells in a column that use the same >>> formula >>> > (and get different results because of relative cell addressing). In UI >>> terms, >>> > write e.g. "=A1*2" to B1, grab the bottom-right corner of the cell and >>> extend >>> > down. But it's implementated this way because that's usually how large >>> > spreadsheets are created. So I think it's a needless complication to >>> be >>> > specific about this. >>> > >>> >>> IMO it's still useful to mention that the optimization is column-based. >>> Because many people don't realize that row-based layout is potentially >>> less efficient. This would be beneficial to those who don't create >>> spreadsheets according to how it's "usually" done. >>> >>> -- >>> Best regards, >>> Mike Kaganski >>> >> _______________________________________________ >> LibreOffice mailing list >> LibreOffice@lists.freedesktop.org >> https://lists.freedesktop.org/mailman/listinfo/libreoffice >> >
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