[ARROW-8012] [C++][CI] Set CTEST_PARALLEL_LEVEL to $concurrency

• Type: Improvement
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 0.16.0
• Component/s: C++, CI, Continuous Integration
• External issue URL: https://github.com/apache/arrow/issues/24228
• Assignee: Unassigned
• Reporter: Ben Kietzman
• Created: 05/Mar/20 16:01
• Updated: 11/Jan/23 07:57

Description

Currently the default test target runs serially while unittest arbitrarily uses 4 threads. On many systems that's suboptimal. The environment variable CTEST_PARALLEL_LEVEL can be set to run tests in parallel, and we should probably have a good default for it (like the hardware concurrency)

https://cmake.org/cmake/help/latest/manual/ctest.1.html