Make playbook slightly less fragile, fix lint error.

README.md

@@ -58,7 +58,9 @@ mpirun -f cluster-hosts ./xhpl
 
 To run locally on a single node, clone or download this repository to the node where you want to run HPL. Make sure the `hosts.ini` is set up with the default options (with just one node, `127.0.0.1`).
 
-Then, run the following command so the cluster networking portion of the playbook is not run:
+All the default configuration from `example.config.yml` should be copied to a `config.yml` file, and all the variables should scale dynamically for your node.
+
+Run the following command so the cluster networking portion of the playbook is not run:
 
 ```
 ansible-playbook main.yml --tags "setup,benchmark"
@@ -95,3 +97,4 @@ Here are a few of the results I've acquired in my testing:
 | DeskPi Super6c (6x CM4 @ 1.5 GHz) | 60.293 Gflops | 40W | 1.50 Gflops/W |
 | DeskPi Super6c (6x CM4 @ 2.0 GHz) | 70.338 Gflops | 51W | 1.38 Gflops/W |
 | M2 MacBook Air (1x M2 @ 3.5 GHz, in Docker) | 104.68 Gflops | TODOW | TODO Gflops/W |
+| M1 Max Mac Studio (1x M1 Max @ 3.2 GHz, in Docker) | TODO Gflops | TODOW | TODO Gflops/W |

example.config.yml

@@ -6,7 +6,7 @@ hpl_root: /opt/top500
 ssh_user: pi
 ssh_user_home: /home/pi
 
-# Replace ansible_memtotal_mb with cluster memory total if running on cluster.
+# Specify manually if needed for mixed-RAM-capacity clusters.
 ram_in_gb: "{{ ( ansible_memtotal_mb / 1024 * 0.75 ) | int | abs }}"
 
 # Count the nodes for accurate HPL.dat calculations.

main.yml

@@ -31,8 +31,8 @@
       ansible.builtin.file:
         path: "{{ item }}"
         state: directory
-        owner: "{{ ansible_user }}"
-        group: "{{ ansible_user }}"
+        owner: "{{ ansible_user | default(ansible_env.USER, true) | default(ansible_user_id, true) }}"
+        group: "{{ ansible_user | default(ansible_env.USER, true) | default(ansible_user_id, true) }}"
         mode: 0755
       loop:
         - "{{ hpl_root }}/tmp"

overclock-pi.yml

@@ -1,3 +1,4 @@
+---
 - name: Set up overclock on Raspberry Pis.
   hosts: cluster
   become: true