[MNG-7174] Parallel builds on macos get the thread count wrong

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Not A Problem
• Affects Version/s: 3.6.3, 3.8.1
• Component/s: Performance
• Environment: macos Big Sur ; java 8 and 11
• Assignee: Unassigned
• Reporter: Sander Verbruggen
• Created: 15/Jun/21 08:01
• Updated: 15/Jun/21 15:21
• Resolved: 15/Jun/21 15:21

Description

When supplying -T1C to do a parallel build on macos, maven counts the logical cores, not the physical ones. This results in the system being overloaded and less responsive (twice the load it can handle).

Steps to reproduce

sysctl -a|grep 'cpu.thread_count|cpu.core_count' gives this output on my machine:

machdep.cpu.core_count: 4
{{ machdep.cpu.thread_count: 8}}

 

Starting a maven session with -T1C shows maven is using 8 threads instead of the expected 4:

[INFO] Using the MultiThreadedBuilder implementation with a thread count of 8