After the work to support 16384 columns in LibreOffice Calc I have also made sure that the feature works also in Collabora Online, thanks to the funding of NGI. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 871498. Since the Calc core is the same, the underlying functionality works just like in LibreOffice. But…
The VLOOKUP spreadsheet function by default requires the searched data to be sorted, and in that case it performs a fast binary search. If the data is not sorted (for example if it would be impractical to have the data that way), it is possible to explicitly tell VLOOKUP that the data is not sorted, in which case Calc did a linear one-by-one lookup. And there are other functions such as COUNTIF or…
So I enabled support for up to 16384 columns in Calc by default some time ago, but just getting it to work was not necessarily the end of the work. Making Calc have 16 times more columns means that any operation that works on entire columns is suddenly 16 times slower, or even worse. Similarly this could easily lead to 16x more memory used. So the support not only needs to work, but it also needs…
So I've been working on improving LO text layout performance, as specified by the TDF tender . As it says, text layout in LO can be rather slow, because of problems like repeated text layout calls for the same text. Let's have a look at a perf profile for PDF export of the document from bug#116400 : There are two major costs here: The first one is splitting text into script runs (separating runs…
So I've updated my Clang to the newly released version 14, and while doing the LibreOffice rebuild afterwards I noticed that it seemed to build faster. I didn't measure it, but the build finished sooner than I expected. So of course I've measured it. As a simple reference I used my year-old post about Clang 11 building faster with PCH , where Calc'c Library_sc built in 4 minutes and 39 seconds.…
Last couple of weeks I have been working on the 16k columns support in Calc. There's been a lot of work on this already by Noel and others, but so far this has been hidden behind the experimental option, and normally documents open only with the "normal" 1024 columns support. The goal of this work is to finish the 16k support stable enough for it to be the default, so that people who need this…
Have you ever edited a document in LibreOffice in more than one window? Right, neither have I. Who'd think about LibreOffice and more than one user at the same time, right? Except ... somebody did and that's how collaborative editing based on LibreOffice works. For whatever strange reason, somewhen in the past somebody thought that implementing multiple views for one document in OpenOffice…
So, current LibreOffice git version now has support for drawing based on Skia also for the Mac. Both Raster and Metal (the Mac GPU framework). Below is the obligatory screenshot, and here is the hey-it-can-be-faster video .
In other words, how much faster will a compiler be after it's been built with various optimizations? Given the recent Clang12 release, I've decided to update my local build of Clang11 that I've been using for building LibreOffice. I switched to using my own Clang build instead of openSUSE packages somewhen in the past because it was faster. I've meanwhile forgot how much faster :), and openSUSE…
With Clang12 almost released, I guess it's high time to write a conclusion to the Clang11 changes that improve compilation times with PCHs . I originally planned to do this after the Clang11 release, but with the process to get the changes reviewed and merged having been so tedious I was glad it was finally over and I couldn't at the time muster the little extra effort to also write this down (I…
So, today I got finally so tired of navigating (or explicitly stepping over) all the internal functions in gdb (you know, all the inline functions from STL containers, from Boost, from this pointer wrapper class, that string class) that I finally googled 'gdb skip system functions'. And guess what, it's been there since gdb 7.12 , from 3 years ago, and it's almost trivial, just adding something…
So, the branch implementing VCL drawing based on the Skia graphics library has been merged in. All(?) the necessary info about how to enable it etc. are in this mail , but there are things that better fit a blog post than a mail, and in this case that's going to be a table and a picture showing how well it may perform. Note that these results are from running visualbackendtest , which is not…
It's been almost half a year since I mentioned how precompiled headers do (not) improve C++ compile times . Quite a long time, filled with doing other things, life, occassionally working on getting my patch production-ready and, last but definitely not least, abandoning that patch and starting from scratch again. It turns out, the problems I mentioned last time had already been more or less solved…
This below is a screenshot of my LibreOffice build using the Skia library. Now, admittedly, this looks way better than it should, as it is actually still far from finished. It is so far X11-only, using the venerable not-that-performant XPutImage(). No Windows, no Vulkan. Yet. Also, while it passes all VCL unit tests, that rather says something about the poor state of coverage of those tests, as…
A new version 1.3 of the distributed C/C++ compilation tool Icecream has been released. To accompany it, version 3.3 of the GUI monitor Icemon has been released as well. The changelogs are here and here . In a less changelog-y way, the changes are: Compiler location are no longer hardcoded anywhere. Previously the compiler automatically packaged and sent to remote nodes was always /usr/bin/gcc (…
Would you like your C++ code to compile twice as fast (or more)? Yeah, so would I. Who wouldn't. C++ is notorious for taking its sweet time to get compiled. I never really cared about PCHs when I worked on KDE, I think I might have tried them once for something and it didn't seem to do a thing. In 2012, while working on LibreOffice, I noticed its build system used to have PCH support, but it had…
If you occassionally do performance profiling as I do, you probably know Valgrind's Callgrind and the related UI KCachegrind. While Callgrind is a pretty powerful tool, running it takes quite a while (not exactly fun to do with something as big as e.g. LibreOffice). Recently I finally gave Linux perf a try. Not quite sure why I didn't use it before, IIRC when I tried it somewhen long ago, it was…
It's been brought to my attention that the Icecream documentation more or less suggests it is necessary to manually set up $ICECC_VERSION (which also involves creating the environment tarball with the compiler and so on). That is incorrect. I've already updated the documentation to say that, like with pretty much everything, Icecream simply figures it out itself by default. So if you happen to use…
A bug has crept into the Icecream 1.0 release that makes the daemon crash on its first start after boot if /var/run is cleared (e.g. it's tmpfs-mounted by systemd). This in practice means that on such systems Icecream does not work unless started manually. So in case your compiles have felt tad a bit slower recently, upgrade to the just released version 1.0.1 . If you run openSUSE, an online…
It's no secret that I use the Clang compiler for development. Although GCC is still somewhat better when things like the performance of the resulting code matter, there are other features that matter more during development. And although again competition helps (it's not difficult to guess where the inspiration for the new error reporting in 4.8 comes from), there are features where I expect it'd…
After almost 10 years since the first version, version 1.0.0 of the Icecream distributed build tool has been released. Yes, it's been almost a decade with us. And as it usually is with versions 1.0.0 after such a long time, it doesn't actually bring anything breadth-taking. But there of course have been some fixes and improvements since version 0.9.7, and in fact even one larger feature found its…
Older blog posts are at http://blogs.kde.org/blog/280 .