multi-core compiling

[michael.s]

I use VisualGDB to crosscompile for the Raspberry. One of the reasons is obviously to speed up the compilation. When I compile my project, I notice that my CPU usage is only between 35-45% and each job seems to be startet consecutivly, like this:

1>  C:/SysGCC/raspberry/bin/arm-linux-gnueabihf-g++.exe -c -pipe -Wno-psabi -std=c++11 -w -g -Wall -W -D_REENTRANT -DQT_WEBKIT -DQT_WEBKIT -DQT_GUI_LIB -DQT_CORE_LIB -Ic:/sysgcc/raspberry/arm-linux-gnueabihf/sysroot/usr/share/qt4/mkspecs/arm-linux-gnueabihf -I. -Ic:/sysgcc/raspberry/arm-linux-gnueabihf/sysroot/usr/include/qt4/QtCore -Ic:/sysgcc/raspberry/arm-linux-gnueabihf/sysroot/usr/include/qt4/QtGui -Ic:/sysgcc/raspberry/arm-linux-gnueabihf/sysroot/usr/include/qt4 -Ic:/SysGCC/raspberry/arm-linux-gnueabihf/sysroot/usr/local/include -IDebug -IDebug -o Debug/MemberData.o Base/MemberData.cpp
1>  C:/SysGCC/raspberry/bin/arm-linux-gnueabihf-g++.exe -c -pipe -Wno-psabi -std=c++11 -w -g -Wall -W -D_REENTRANT -DQT_WEBKIT -DQT_WEBKIT -DQT_GUI_LIB -DQT_CORE_LIB -Ic:/sysgcc/raspberry/arm-linux-gnueabihf/sysroot/usr/share/qt4/mkspecs/arm-linux-gnueabihf -I. -Ic:/sysgcc/raspberry/arm-linux-gnueabihf/sysroot/usr/include/qt4/QtCore -Ic:/sysgcc/raspberry/arm-linux-gnueabihf/sysroot/usr/include/qt4/QtGui -Ic:/sysgcc/raspberry/arm-linux-gnueabihf/sysroot/usr/include/qt4 -Ic:/SysGCC/raspberry/arm-linux-gnueabihf/sysroot/usr/local/include -IDebug -IDebug -o Debug/Message.o Base/Message.cpp

compiling under a SDD the bottleneck here is probably not the hdd, but the insufficient use of all the cores. under VS i could normally add the -MPXX flag or with make the ‘-j’ flag. how can i speed it up using virtualGDB

thanks

[support]

Hi,

Simply add “-j <number of cores>” to the Make command line arguments in VisualGDB Project Properties to enable parallel building.

[b.timofte]

Where should i add this option ? Your answer is not clear

[support]

Hi,

Sorry for the confusion. Please refer to the screenshot below for details:

Note that $(LocalMultiThreadedBuildFlags) is case-sensitive. It will automatically be replaced with -j(number of CPU cores on your machine) during build.

[thm]

Thanks, this makes a huge difference.

Is there a reason why its not enabled by default for new projects?

[support]

Hi,

Yes, it sometimes causes Make to simply hang. VisualGDB 5.2 will come with a separate MSBuild platform that will integrate the existing toolchains directly into the Visual Studio build system, so the multi-threaded build will be automatic and it won’t trigger the Make bug.

[Author]

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