diff --git a/roles/validate-tempest/README.md b/roles/validate-tempest/README.md
index 5f5b440ec..b7cd83215 100644
--- a/roles/validate-tempest/README.md
+++ b/roles/validate-tempest/README.md
@@ -24,7 +24,7 @@ Role Variables
                        to empty if you don't want to run with blacklist_file option.
                        Default value is an empty list
 * `skip_file_src`: path to skip tests file, set it empty if running without skip list: `skip_file_src=''`
-* `tempest_workers`: int - how many parallel workers to run (default is number of cores)
+* `tempest_workers`: int - how many parallel workers to run (default is half the number of cores/threads)
 * `tempest_until_failure`: false/true - default is false, repeat the run again and again until failure occurs
 * `tempest_exit_on_failure`: true/false - whether to exit from role with tempest exit code (default: true)
 * `tempestmail_config`: config.yaml - name of config file for tempestmail script
diff --git a/roles/validate-tempest/tasks/pre-tempest.yml b/roles/validate-tempest/tasks/pre-tempest.yml
index 44ed7eb74..b7385b2c4 100644
--- a/roles/validate-tempest/tasks/pre-tempest.yml
+++ b/roles/validate-tempest/tasks/pre-tempest.yml
@@ -1,7 +1,7 @@
 ---
 - name: Set the number of workers in tempest
   set_fact:
-      tempest_workers: "{{ ansible_processor_count|int // 2 }}"
+      tempest_workers: "{{ ansible_processor_vcpus|int // 2 }}"
   when: tempest_workers is not defined
 
 - name: Create overcloud tempest setup script