OCPBUGS-83865: Revert stalld backend to sched_debug by bartwensley · Pull Request #1515 · openshift/cluster-node-tuning-operator

bartwensley · 2026-05-13T20:03:48Z

Updating the MC to revert the stalld backend to sched_debug. This is necessary because the new default queue_task backend causes an unacceptable latency penalty (see RHEL-175242).

Summary by CodeRabbit

New Features
- The stalld daemon is now automatically configured to use the sched_debug backend during system initialization to support performance profiles.
Tests
- Added tests to validate that the stalld backend configuration is generated and included in rendered system configuration.

openshift-ci-robot · 2026-05-13T20:03:56Z

@bartwensley: This pull request references Jira Issue OCPBUGS-83865, which is valid.

3 validation(s) were run on this bug

bug is open, matching expected state (open)
bug target version (5.0.0) matches configured target version for branch (5.0.0)
bug is in the state POST, which is one of the valid states (NEW, ASSIGNED, POST)

Requesting review from QA contact:
/cc @dgonyier

The bug has been updated to refer to the pull request using the external bug tracker.

Details

In response to this:

Updating the MC to revert the stalld backend to sched_debug. This is necessary because the new default queue_task backend causes an unacceptable latency penalty (see RHEL-175242).

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the openshift-eng/jira-lifecycle-plugin repository.

coderabbitai · 2026-05-13T20:04:02Z

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository: openshift/coderabbit/.coderabbit.yaml

Review profile: CHILL

Plan: Enterprise

Run ID: 460527a8-2ee4-4b28-8448-bc85a8d2cb5e

📥 Commits

Reviewing files that changed from the base of the PR and between ad02c11 and 4f402e3.

📒 Files selected for processing (12)

pkg/performanceprofile/controller/performanceprofile/components/machineconfig/machineconfig.go
pkg/performanceprofile/controller/performanceprofile/components/machineconfig/machineconfig_test.go
test/e2e/performanceprofile/testdata/render-expected-output/bootstrap/extra-mcp/openshift-bootstrap-master_machineconfig.yaml
test/e2e/performanceprofile/testdata/render-expected-output/bootstrap/extra-mcp/openshift-bootstrap-worker_machineconfig.yaml
test/e2e/performanceprofile/testdata/render-expected-output/bootstrap/no-mcp/openshift-bootstrap-master_machineconfig.yaml
test/e2e/performanceprofile/testdata/render-expected-output/bootstrap/no-mcp/openshift-bootstrap-worker_machineconfig.yaml
test/e2e/performanceprofile/testdata/render-expected-output/default/arm/manual_machineconfig.yaml
test/e2e/performanceprofile/testdata/render-expected-output/default/cpuFrequency/manual_machineconfig.yaml
test/e2e/performanceprofile/testdata/render-expected-output/default/manual_machineconfig.yaml
test/e2e/performanceprofile/testdata/render-expected-output/default/pp-norps/manual_machineconfig.yaml
test/e2e/performanceprofile/testdata/render-expected-output/manual_machineconfig.yaml
test/e2e/performanceprofile/testdata/render-expected-output/no-ref/manual_machineconfig.yaml

✅ Files skipped from review due to trivial changes (1)

test/e2e/performanceprofile/testdata/render-expected-output/default/pp-norps/manual_machineconfig.yaml

🚧 Files skipped from review as they are similar to previous changes (2)

pkg/performanceprofile/controller/performanceprofile/components/machineconfig/machineconfig_test.go
pkg/performanceprofile/controller/performanceprofile/components/machineconfig/machineconfig.go

Walkthrough

The machineconfig component now unconditionally writes two files into generated Ignition MachineConfigs: /etc/sysconfig/stalld-backend setting BE="-b sched_debug", and a systemd drop-in /etc/systemd/system/stalld.service.d/stalld-backend.conf that loads that EnvironmentFile. A unit test verifies both files are present and contain the expected contents.

Changes

Stalld sched_debug Backend Configuration

Layer / File(s)	Summary
Stalld backend sysconfig and systemd drop-in `pkg/performanceprofile/controller/performanceprofile/components/machineconfig/machineconfig.go`	`getIgnitionConfig` now adds two storage files to Ignition: `/etc/sysconfig/stalld-backend` with `BE="-b sched_debug"` and `/etc/systemd/system/stalld.service.d/stalld-backend.conf` containing `EnvironmentFile=/etc/sysconfig/stalld-backend`, both created with mode `0644` via `addContent`.
Unit test: verify generated Ignition files `pkg/performanceprofile/controller/performanceprofile/components/machineconfig/machineconfig_test.go`	New Ginkgo `Context("stalld backend configuration")` unmarshals the generated Ignition config, base64-decodes storage file contents, and asserts the presence and exact contents of the sysconfig and systemd drop-in files.
Rendered MachineConfig fixtures updated `test/e2e/performanceprofile/testdata/render-expected-output//manual_machineconfig.yaml`, `.../bootstrap/_machineconfig.yaml`, `.../default/**/manual_machineconfig.yaml`, `.../no-ref/manual_machineconfig.yaml`	Updated expected output fixtures to include the two new `spec.config.storage.files` entries (sysconfig and systemd drop-in) with base64-encoded contents and appropriate file metadata in multiple test variants.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

🚥 Pre-merge checks | ✅ 10 | ❌ 2

❌ Failed checks (2 warnings)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.
Test Structure And Quality	⚠️ Warning	All 5 Expect calls lack assertion messages. Codebase pattern shows tests should include meaningful failure messages, as seen in lines 114 and 167 of the same file.	Add assertion messages to all Expect calls (lines 266, 269, 275, 279, 280) to help diagnose failures when assertions fail.

✅ Passed checks (10 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly describes the main change: reverting stalld backend configuration to sched_debug, which aligns with all the code and test data changes across multiple machine config files.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Stable And Deterministic Test Names	✅ Passed	All test names in the PR are stable and deterministic. The new stalld test uses static descriptive names with no dynamic content, timestamps, UUIDs, or other changing values.
Microshift Test Compatibility	✅ Passed	No new e2e tests added. The test added in machineconfig_test.go is a unit test in pkg/, not an e2e test in test/e2e/. The custom check applies only to e2e tests.
Single Node Openshift (Sno) Test Compatibility	✅ Passed	No e2e tests were added in this PR. The new Ginkgo test is a unit test in pkg/ (not test/e2e/). The SNO compatibility check applies only to e2e tests.
Topology-Aware Scheduling Compatibility	✅ Passed	No pod scheduling constraints introduced. Changes are node-level system config via MachineConfig/Ignition, topology-agnostic across SNO, TNF, TNA, HyperShift.
Ote Binary Stdout Contract	✅ Passed	No OTE Binary Stdout Contract violations. Main code only adds Ignition config content. Test changes are within Ginkgo test blocks where output is intercepted. No process-level code writes to stdout.
Ipv6 And Disconnected Network Test Compatibility	✅ Passed	New Ginkgo test is a unit test (not e2e) with no IPv4 assumptions or external connectivity requirements. Test only validates Ignition config generation with base64 decoding.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

🧪 Generate unit tests (beta)

Create PR with unit tests

Warning

There were issues while running some tools. Please review the errors and either fix the tool's configuration or disable the tool if it's a critical failure.

🔧 golangci-lint (2.12.2)

level=error msg="Running error: context loading failed: failed to load packages: failed to load packages: failed to load with go/packages: err: exit status 1: stderr: go: inconsistent vendoring in :\n\tgithub.com/RHsyseng/operator-utils@v1.4.13: is explicitly required in go.mod, but not marked as explicit in vendor/modules.txt\n\tgithub.com/coreos/go-systemd@v0.0.0-20191104093116-d3cd4ed1dbcf: is explicitly required in go.mod, but not marked as explicit in vendor/modules.txt\n\tgithub.com/coreos/ignition@v0.35.0: is explicitly required in go.mod, but not marked as explicit in vendor/modules.txt\n\tgithub.com/coreos/ignition/v2@v2.26.0: is explicitly required in go.mod, but not marked as explicit in vendor/modules.txt\n\tgithub.com/docker/go-units@v0.5.0: is explicitly required in go.mod, but not marked as explicit in vendor/modules.txt\n\tgithub.com/go-logr/stdr@v1.2.2: is explicitly required in go.mod, but not marked as explicit in vendor/modules.txt\n\tgithub.com/google/go-cmp@v0.7.0

... [truncated 19340 characters] ...

is replaced in go.mod, but not marked as replaced in vendor/modules.txt\n\tk8s.io/legacy-cloud-providers: is replaced in go.mod, but not marked as replaced in vendor/modules.txt\n\tk8s.io/metrics: is replaced in go.mod, but not marked as replaced in vendor/modules.txt\n\tk8s.io/mount-utils: is replaced in go.mod, but not marked as replaced in vendor/modules.txt\n\tk8s.io/pod-security-admission: is replaced in go.mod, but not marked as replaced in vendor/modules.txt\n\tk8s.io/sample-apiserver: is replaced in go.mod, but not marked as replaced in vendor/modules.txt\n\tgithub.com/onsi/ginkgo/v2: is replaced in go.mod, but not marked as replaced in vendor/modules.txt\n\n\tTo ignore the vendor directory, use -mod=readonly or -mod=mod.\n\tTo sync the vendor directory, run:\n\t\tgo mod vendor\n"

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openshift-ci · 2026-05-13T20:04:11Z

@openshift-ci-robot: GitHub didn't allow me to request PR reviews from the following users: dgonyier.

Note that only openshift members and repo collaborators can review this PR, and authors cannot review their own PRs.

Details

In response to this:

@bartwensley: This pull request references Jira Issue OCPBUGS-83865, which is valid.

3 validation(s) were run on this bug

bug is open, matching expected state (open)

bug target version (5.0.0) matches configured target version for branch (5.0.0)

bug is in the state POST, which is one of the valid states (NEW, ASSIGNED, POST)

Requesting review from QA contact:
/cc @dgonyier

The bug has been updated to refer to the pull request using the external bug tracker.

In response to this:

Updating the MC to revert the stalld backend to sched_debug. This is necessary because the new default queue_task backend causes an unacceptable latency penalty (see RHEL-175242).

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the openshift-eng/jira-lifecycle-plugin repository.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

openshift-ci · 2026-05-13T20:04:22Z

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: bartwensley
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bartwensley · 2026-05-13T20:08:26Z

/cc @MarSik

bartwensley · 2026-05-13T20:22:57Z

Looks like I need to update some e2e tests...

Updating the MC to revert the stalld backend to sched_debug. This is necessary because the new default queue_task backend causes an unacceptable latency penalty (see RHEL-175242). Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com> Signed-off-by: Bart Wensley <bwensley@redhat.com>

bartwensley · 2026-05-14T04:06:57Z

/retest

openshift-ci · 2026-05-14T05:15:49Z

@bartwensley: all tests passed!

Full PR test history. Your PR dashboard.

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bartwensley · 2026-05-14T11:47:04Z

/cc @browsell

MarSik · 2026-05-14T14:16:35Z

 	})

+	Context("stalld backend configuration", func() {
+		It("should include stalld sysconfig and systemd dropin files", func() {


This is checking the files, but not whether systemd consumed them. You should probably add an e2e test too that makes sure systemd noticed the files. See https://github.com/openshift/cluster-node-tuning-operator/blob/main/test/e2e/performanceprofile/functests/utils/systemd/systemd.go#L17 for helper functions. And probably place the test somewhere here https://github.com/openshift/cluster-node-tuning-operator/blob/main/test/e2e/performanceprofile/functests/1_performance/performance.go

openshift-ci Bot requested review from ffromani and jmencak May 13, 2026 20:04

bartwensley mentioned this pull request May 13, 2026

OCPBUGS-83865: Add MC to change stalld backend openshift-kni/telco-reference#757

Open

openshift-ci Bot requested a review from MarSik May 13, 2026 20:08

bartwensley marked this pull request as draft May 13, 2026 20:22

openshift-ci Bot added the do-not-merge/work-in-progress Indicates that a PR should not merge because it is a work in progress. label May 13, 2026

bartwensley force-pushed the stalld-backend branch from ad02c11 to 4f402e3 Compare May 13, 2026 20:41

bartwensley marked this pull request as ready for review May 13, 2026 22:19

openshift-ci Bot removed the do-not-merge/work-in-progress Indicates that a PR should not merge because it is a work in progress. label May 13, 2026

openshift-ci Bot requested a review from browsell May 14, 2026 11:47

MarSik reviewed May 14, 2026

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OCPBUGS-83865: Revert stalld backend to sched_debug#1515

OCPBUGS-83865: Revert stalld backend to sched_debug#1515
bartwensley wants to merge 1 commit into
openshift:mainfrom
bartwensley:stalld-backend

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