ci: avoid synchronising scheduled jobs

.github/workflows/bpf-next-test.yml

@@ -1,9 +1,9 @@
 name: bpf-next-test
 
 on:
-  # only runs on main, every 6 hours
-    schedule:
-      - cron: "0 */6 * * *"
+  # only runs on main, every 6 hours. specify hours explicitly so scheduled runs can be offset and use a random minute.
+  schedule:
+    - cron: "35 0,6,12,18 * * *"
 
 jobs:
   build-kernel:

.github/workflows/caching-build.yml

@@ -1,12 +1,12 @@
 name: build-and-test
 
 on:
-  # only runs on main, hourly cache update used by all branches
-    schedule:
-      - cron: "0 * * * *"
-    push:
-    pull_request:
-    merge_group:
+  # only runs on main, hourly cache update used by all branches. random minute to avoid synchronised scheduled workflows.
+  schedule:
+    - cron: "8 * * * *"
+  push:
+  pull_request:
+  merge_group:
 
 jobs:
   lint:

.github/workflows/for-next-test.yml

@@ -1,9 +1,9 @@
 name: for-next-test
 
 on:
-  # only runs on main, every 6 hours
-    schedule:
-      - cron: "0 */6 * * *"
+  # only runs on main, every 6 hours. specify hours explicitly so scheduled runs can be offset and use a random minute.
+  schedule:
+    - cron: "22 1,7,13,19 * * *"
 
 jobs:
   build-kernel:

.github/workflows/stable.yml

@@ -1,9 +1,9 @@
 name: stable-test
 
 on:
-  # only runs on main, every 6 hours
+  # only runs on main, every 6 hours. specify hours explicitly so scheduled runs can be offset and use a random minute.
   schedule:
-    - cron: "0 */6 * * *"
+    - cron: "40 2,8,14,20 * * *"
 
 jobs:
   build-kernel: