https://issues.dlang.org/show_bug.cgi?id=20567

          Issue ID: 20567
           Summary: GC should not start threads for parallel marking in
                    simple programs
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: enhancement
          Priority: P1
         Component: druntime
          Assignee: nobody@puremagic.com
          Reporter: r.sagitario@gmx.de

A simple program like

void main()
{
    char[] buf = new char[2048];
}

runs 3 collections and starts multiple threads for parallel marking. This should be avoided by default.

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