document circleci attempt

.circleci/config.yml

@@ -28,6 +28,8 @@ jobs:
       - run: nproc
       - run: date > my-artifact
       - run: ./setup -y
+      # nproc one because CircleCI lies about actual CPUs we have (1) and build fails:
+      # https://ideas.circleci.com/ideas/CCI-I-578
       - run: ./build --arch aarch64 --download-dependencies --nproc 1 gem5
       - store_artifacts:
           path: my-artifact

.travis.yml

@@ -1,3 +1,5 @@
+# https://github.com/cirosantilli/linux-kernel-module-cheat#travis
+
 language: cpp
 
 sudo: required

README.adoc

@@ -15461,10 +15461,31 @@ cd -
 ./bench-all -A
 ....
 
-=== Travis
+=== Continuous integraion
+
+We have exploreed a few Continuous integration solutions.
+
+We haven't setup any of them yet.
+
+==== Travis
 
 We tried to automate it on Travis with link:.travis.yml[] but it hits the current 50 minute job timeout: https://travis-ci.org/cirosantilli/linux-kernel-module-cheat/builds/296454523 And I bet it would likely hit a disk maxout either way if it went on.
 
+==== CircleCI
+
+This setup sucessfully built gem5 on every commit: link:.circleci/config.yml[]
+
+Enabling it is however blocked on: https://github.com/cirosantilli/linux-kernel-module-cheat/issues/79 so we disabled the builds on the web UI.
+
+If that ever gets done, we will also need to:
+
+* convert this to a nightly with a workflow, to save server resources: https://circleci.com/docs/2.0/configuration-reference/#triggers
+* download the prebuilt disk images and enable caches to save the images across runs
+
+A build took about 1 hour of a core, and the free tier allows for 1000 minutes per month: https://circleci.com/pricing/ so about 17 hours. The cheapest non-free setup seems to be 50 dollars per month gets us infinite build minutes per month and 2 containers, so we could scale things to run in under 24 hours.
+
+There is no result reporting web UI however... but neither does GitLab CI: https://gitlab.com/gitlab-org/gitlab-ce/issues/17081
+
 === Benchmark this repo benchmarks
 
 ==== Benchmark Linux kernel boot