WSL Ubuntu 18.04 shows wrong Cpu_allowed mask

Ubuntu 18.04 running under WSL detects my CPU wrong: $ cat /proc/self/status | grep Cpus_allowed Cpus_allowed: 00000001 The CPU is an i7-4510U (2 cores/4 threads) so I expected: Cpus_allowed: f or similar (ff, ffffffff, 0000000f). The peculiar thing is that when I run 4 processes, each process gets a CPU thread, and thus runs at 400% CPU utilization. So it is as if the CPU mask is not respected. Also taskset is not respected. This should use a single thread (100%), but it uses all 4 (400%): taskset 2 parallel -j4 'bzip2 ' ::: {1..10} Is this a bug - possibly in WSL? And if so: Where do I report it? **Background** The problem described on https://arstechnica.com/civis/viewtopic.php?f=15&t=1442563 is explained by the above: GNU Parallel detects the wrong number of CPU threads because it looks at the CPU mask in /proc/*/status to determine how many CPU threads it is allowed to use.