Hi, I have got a fix for macOS (in LLVM), and a similar patch that _might_ improve things on Windows too
https://codereview.qt-project.org/c/clang/llvm-project/+/382042 but since we fail to reproduce the huge difference between "compiling" and "clangd indexing" that you observe in the first place, we have a difficult time verifying that this indeed helps. We have created a build of clangd with the potential fix and I've uploaded it here: https://download.qt.io/development_releases/prebuilt/libclang/testing/ it would be great if you could test if this improves things for you. Set the path to the new clangd in Tools > Options > C++ > Clangd > Path to executable. Br, Eike > On Nov 9, 2021, at 15:26, Eike Ziller <eike.zil...@qt.io> wrote: > > I can confirm on macOS, that Qt Creator in Qt Creator takes 2 1/2 hours to > index, on a machine that takes 12 minutes to build it. > clangd uses 12 threads by default, but only 4 out of 8 cores. Turning up the > number of "worker threads" does increase the number of threads used, but > doesn't increase the cores/CPU used and doesn't make indexing faster. > > The good thing is that the full indexing is only done once (cached per build > directory), and further updates just index what has changed. > > It seems to be known in principle in the Clangd project: > > clangd is keeping notify indexing and won't stop in Windows with Chromium · > Issue #643 · clangd/clangd > https://github.com/clangd/clangd/issues/643 > > and seems to be different on Linux. > > Br, Eike > >> On Nov 8, 2021, at 19:57, Adam Light <acli...@gmail.com> wrote: >> >> Hi >> >> I'm using QtC 6.0.0-beta2 on Windows 10. >> >> I wanted to give clang a try so I enabled the "Use clangd" option. I have >> Enabled background indexing checked, worker thread count set to Automatic, >> and Document update threshold set to 500ms. >> >> I deleted all of the build directories for my project and then opened the >> project in Creator. After a few seconds a "Parsing C/C++ files (clangd)" >> popup appeared with a progress bar and file count. It shows that it needs to >> parse 3495 files. >> >> After having run for 15 minutes now, the popup says that 216 files have been >> parsed. >> >> Building a debug build of this qmake-based project on this Windows machine >> takes about 2 minutes. That is using the MSVC compiler, not clang. The >> machine has a 16 core/32 thread processor and 32GB RAM. Building the same >> project on an older Macintosh machine with 4 cores/8 threads takes about 5-6 >> minutes. In that case clang is the compiler. >> >> I collected some ETW traces and I verified that clangd is running in 16 >> threads. Unfortunately, the debug symbols for Creator >> (https://download.qt.io/development_releases/qtcreator/6.0/6.0.0-beta2/installer_source/windows_x64/qtcreator-debug.7z) >> do not include symbols for clangd, so I have no idea what the bottleneck is. >> >> I realize that clangd is considered experimental, but surely it's not this >> slow for others, right? If this isn't expected, I'm open to helping to debug >> what's going on, if someone has ideas about how to do so. >> >> Thanks >> Adam >> >> PS: As I am about to send this, it's been 26 minutes since parsing started, >> and it's finished only 375 files. >> _______________________________________________ >> Qt-creator mailing list >> Qt-creator@qt-project.org >> https://lists.qt-project.org/listinfo/qt-creator > -- Eike Ziller Principal Software Engineer The Qt Company GmbH Erich-Thilo-Straße 10 D-12489 Berlin eike.zil...@qt.io http://qt.io Geschäftsführer: Mika Pälsi, Juha Varelius, Jouni Lintunen Sitz der Gesellschaft: Berlin, Registergericht: Amtsgericht Charlottenburg, HRB 144331 B _______________________________________________ Qt-creator mailing list Qt-creator@qt-project.org https://lists.qt-project.org/listinfo/qt-creator
