How do I turn on multi-CPU/Core C++ compiles in the Visual Studio IDE (2008)?

Question

I have a Visual Studio 2008 C++ project that has support for using multiple CPUs/cores when compiling. In the VCPROJ file I see this:

<Tool
    Name="VCCLCompilerTool"
    AdditionalOptions="/MP"
    ...

I can't find where that was turned added via the IDE and I want to set up another project that uses all of my cores during compilation.

I found tons of references to the MSDN /MP page but that is for using the command line; I have yet to find any references to setting that with the IDE. How do I do that?

EDIT: To clarify, the two projects are completely separate and are not in the same VCPROJ file. I wanted to turn on support for multiple cores during the C++ compilation phase.

Solution 1

To enable /MP option you could add it to Project Settings->C/C++->Command Line|Additional options. This is the only way to switch it on in vcproj.

Solution 2

Tools > Options > Projects and Solutions > Build and Run > maximum number of parallel project builds

Comments

[dwj]

Both my projects have "maximum number of parallel project builds" set to 2 (which is correct) but the original project shows the /MP switch and my new project doesn't. When I compile both projects, the original is definitely using multiple cores while the new one is not.

[Kirill V. Lyadvinsky]

You will not switch on /MP build via that settings. This option will enable parallel builds of several projects in one solution, not several files in one project. This option suitable only for big solutions.

[dwj]

This worked. As a test I jammed it into the VCPROJ directly. After seeing your post, I added it to the section you show above -- it's exactly the same thing.

[Armentage]

The difference between this and the Build-And-Run option is that /MP allows MULTIPLE FILES from ONE project to compile in parallel, while the build-and-run option allows MULTIPLE PROJECTS to build at the same time. The two options are orthogonal.

[metal]

You may also need to disable the /Gm option, which enables minimal rebuild, under Code Generation.

[Camille Goudeseune]

To get all the CPU meters in Task Manager dancing at once, you might need to hardcode the number. For example, on a 6-core i5, /MP12 instead of just /MP. This depends on hyperthreading settings, etc.

[James Bedford]

@metal, so I have to trade off multi-core compilation of the entire project with single-core compilation of the minimum rebuild..? I'm either wasting cores or I'm doing an incredibly inefficient build.. :/