On Tue, 16 Jul 2019 at 18:29, Christian Gagneraud <chg...@gmail.com> wrote: > The compiler flags are not the same, but not so far off: > Qbs: -g -O0 -Wall -Wextra -m64 -pipe -fexceptions -fvisibility=hidden > -fvisibility-inlines-hidden -fPIC > CMake: -g -O0 -std=c++14 -fvisibility=hidden > -fvisibility-inlines-hidden -fPIC -fstack-protector-strong -Wformat > -Wformat-security
Maybe the use of -pipe has noticeable effects. I'm currently running builds with incremental parallel jobs and i record the load average history. When building with Qbs I can clearly see "stairs" (except for high parallel jobs), with CMake it's difficult to spot as if there was a lot of noise. As well, i've now disabled building unit tests and qbs when building with qbs, the comparison should now be more fair: time qbs -f ../qtcreator.qbs -j $jobs profile:qt-5-12-2 project.withAutotests:false vs cmake -DCMAKE_BUILD_TYPE=Debug -DCMAKE_CXX_FLAGS_DEBUG="-O0 -g" -G Ninja .. time ninja -j $jobs Qbs builds QtCreator in 2:46, ninja in 4:55 (not counting the initial cmake call which would add 5+ seconds), the ratio is 0.56, basically Qbs is twice as fast when using all the available cores on this particular machine/env. I think i'll try to match the compiler flags exactly, and use tmpfs for /tmp and the build dir. This should remove most of the IOs "noise" What i've noticed so far is that ninja use a shell to run the compiler, and AFAIU, ninja calls "cmake -E cmake_autogen", to handle Qt's moc. Weird.... Chris _______________________________________________ Qbs mailing list Qbs@qt-project.org https://lists.qt-project.org/listinfo/qbs
