CMake Cookbook

How it works

We can see that in the parallel case, tests j, i, h, and e started at the same time. The reduction in total test time when running in parallel can be significant. Looking at the output from ctest --parallel 4, we can see that the parallel test run started with the longest tests, and ran the shortest tests at the end. Starting with the longest tests is a very good strategy. It is like packing moving boxes: we start with larger items, and fill in the gaps with smaller items. Comparing the stacking of the a-j tests on four cores, when starting with the longest, looks as follows:

        --> timecore 1: jjjjjjjjjcore 2: iiiiiiibdcore 3: hhhhhgggcore 4: eeefffac

Running tests in the order in which they are defined looks as follows:

 --> ...