roles/run-tempest/tasks/main.yaml

# NOTE(andreaf) The number of vcpus is not available on all systems.
# See https://github.com/ansible/ansible/issues/30688
# When not available, we fall back to ansible_processor_cores
- name: Get hw.logicalcpu from sysctl
  shell: sysctl hw.logicalcpu | cut -d' ' -f2
  register: sysctl_hw_logicalcpu
  when: ansible_processor_vcpus is not defined

- name: Number of cores
  set_fact:
    num_cores: "{{ansible_processor_vcpus|default(sysctl_hw_logicalcpu.stdout)}}"

- name: Set concurrency for cores == 3 or less
  set_fact:
    default_concurrency: "{{ num_cores }}"
  when: num_cores|int <= 3

- name: Limit max concurrency when more than 3 vcpus are available
  set_fact:
    default_concurrency: "{{ num_cores|int // 2 }}"
  when: num_cores|int > 3

- name: Run Tempest
  command: tox -e {{tox_venvlist}} -- {{tempest_test_regex|quote}} --concurrency={{tempest_concurrency|default(default_concurrency)}}
  args:
    chdir: "{{devstack_base_dir}}/tempest"
  become: true
  become_user: tempest