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38039415f8
We have our own GitLab-CI runner, but with only one we can't run many
jobs in parallel so it takes a very long time before all the tests have
completed. In addition, if that runner goes down, we have nothing at
all.
GitLab offers the following machine types for hosted runners on Linux
x86-64 [1]. The default is the "small" runner. Using a larger runner
increases the "Cost factor" [2]:
Runner Tag vCPUs Memory Storage Cost factor
saas-linux-small-amd64 (default) 2 8 GB 30 GB 1
saas-linux-medium-amd64 4 16 GB 50 GB 2
saas-linux-large-amd64 (Premium and Ultimate only) 8 32 GB 100 GB 3
saas-linux-xlarge-amd64 (Premium and Ultimate only) 16 64 GB 200 GB 6
saas-linux-2xlarge-amd64 (Premium and Ultimate only) 32 128 GB 200 GB 12
Compute minutes consumed by a job is calculated by:
Job duration / 60 * Cost factor
(Job duration: The time, in seconds, that a job took to run, not
including time spent in the created or pending statuses.)
Thanks to the GitLab OSS program [3], Buildroot benefits from a free
Ultimate subscription and can use GitLab shared runners tagged with
saas-linux-{large, xlarge, 2xlarge}-amd64. In addition, we receive
50,000 free runner minutes per month.
For opensource projects, the Cost factor is reduced by 0,5 (1 minute per
2 minutes of job time).
In order to use one of those tags in Buildroot GitLab-CI jobs, we have
to classify all tests by resource requirement, to make sure the job
doesn't fail because it times out or has insufficient memory or disk
space. We also don't want to use the largest runner for everything
because that would spend the minutes very quickly while the resources
aren't used efficiently (mostly serialized).
First we introduce some new templates used to add the corresponding
runner tag to a runtime test job (reusing the GitLab terminology).
.runner-{small,medium,large,xlarge,2xlarge}
Most of our tests are fast (checkpackage, test_external_bootlin...), so
saas-linux-small-amd64 runner tag is enough. Default to this tag if
nothing else is specified.
Add a comment next to the test class to provide the runner tag.
This runner tag is retrieved when generating the
generated-gitlab-ci.yml file used to create the child pipeline where
the runtime test jobs are executed.
We use the list of runtime tests returned by node2:
"tests.boot.test_edk2.TestEdk2.test_run"
We convert each element of this list to get the path to the test source
file and the name of the test:
"support/testing/tests/boot/test_edk2.py"
TestEdk2
With that, we can grep into the test source file to retrieve the runner
tag placed one line above the test class:
# GitLab-runner: large
class TestEdk2(infra.basetest.BRTest):
Once the runner tag is retrieved, it's used to use the corresponding
runner template to the runtime test job:
tests.boot.test_edk2.TestEdk2.test_run: { extends: [ .runtime_test_base, .runner-large ]}
GitLab runners hosted by the Buildroot project should be able to run any
jobs, so a specific runner tag "buildroot-runner" is used to allow
running a job on such runners. The "buildroot-runner" tag is used in
addition to GitLab ones to run a job on the Buildroot runner or on a
shared GitLab-CI runner.
If a test can't be executed by any shared GitLab-CI runners, we have
to use a runner owned by the Buildroot project. In this case we have
to use a specific template ".runner-buildroot-runner-only". There is no
such runtime test at the moment.
The proposed classification is based on a previous pipeline analysis
[5]:
- Tests lasting more than 3 hours will use 2xlarge runners.
- Tests lasting more than 2 hours will use xlarge runners.
- Tests lasting more than 1 hours will use large runners.
- Tests building a kernel or a toolchain will use medium runners.
- All other tests will use small runners when possible.
CI minute cost estimate:
tests.package.test_clang.TestClangCompilerRT.test_run lasts 4h25 on the
Buildroot runner. If we this duration for 2xlarge runners, the CI
minute consumed would be:
(265 / 60) * 12 * 0.5 = 26,5
With 6 jobs using a 2xlarge runners we used ~160 CI minutes.
tests.package.test_kmscube.TestKmsCube.test_run list 2h04 on the
Buildroot runner. If we this duration for xlarge runners, the CI
minute consumed would be:
(124 / 60) * 6 * 0.5 = 6,2
With 4 jobs using a xlarge runners we used ~37 CI minutes.
tests.package.test_weston.TestWeston.test_run last 1h15 on th
Buildroot runner. If we this duration for large runners, the CI
minute consumed would be:
(75 / 60) * 3 * 0.5 = 1.87
With 28 jobs using a large runners we used ~53 CI minutes.
tests.package.test_gstreamer1.TestGstreamer1.test_run last 46min on the
Buildroot runner. If we this duration for large runners, the CI
minute consumed would be:
(46 / 60) * 2 * 0.5 = 0.76
With 31 jobs using a medium runners we used ~24 CI minutes.
tests.package.test_python.TestPython3Py.test_run last 13min on the
Buildroot runner. If we this duration for large runners, the CI
minute consumed would be:
(13 / 60) * 1 * 0.5 = 0.1
With 691 jobs using a medium runners we used ~69 CI minutes.
In total, one pipeline for the runtime tests cost ~350 CI minutes.
We run such pipeline once a week (on Monday), one for each Buildroot
releases every 3 month, one for each stable and LTS release per month,
and one for each release candidate (3).
Worst case (realse month):
(4 weeks + 1 release + 1 stable + 1 LTS + 3 release candidate) * 350 CI
minutes: 3500 CI minutes / 50000.
So we should be able to run our pipeline without exhausting our CI
minutes credit.
[1] https://docs.gitlab.com/ci/runners/hosted_runners/linux/#machine-types-available-for-linux---x86-64
[2] https://docs.gitlab.com/ci/pipelines/compute_minutes/#cost-factors
https://docs.gitlab.com/ci/pipelines/compute_minutes/#compute-usage-calculation
https://docs.gitlab.com/ci/pipelines/compute_minutes/#cost-factors-of-hosted-runners-for-gitlabcom
[3] https://gitlab.com/buildroot.org/gitlab-oss
[4] https://docs.gitlab.com/ci/runners/hosted_runners/#gitlabcom-hosted-runner-workflow
[5] https://gitlab.com/buildroot.org/buildroot/-/pipelines/2416603721
Signed-off-by: Romain Naour <romain.naour@smile.fr>
[Arnout:
- simplify parsing of test_file and test_name;
- match the entire test_name instead of substring;
- assume "small" by default;
- remove the "small" tags;
- use "gitlab-runner" instead of "Gitlab-runner".
]
Signed-off-by: Arnout Vandecappelle <arnout@rnout.be>