chore: remove lazy loading to demonstrate regression - #17690
Closed
hebaalazzeh wants to merge 3 commits into
Closed
Conversation
Contributor
|
Note Gemini is unable to generate a review for this pull request due to the file types involved not being currently supported. |
hebaalazzeh
added a commit
that referenced
this pull request
Jul 14, 2026
## Overview This PR integrates the import profiler script (introduced in #17467) into our automated CI pipeline. Why this matters: Import times significantly impact CLI responsiveness and cold starts for Serverless products like Cloud Run and Cloud Functions. Ideally, library imports should stay under 500ms, and anything taking over 1 second is a target for optimization. This CI check helps us proactively track metrics like import latency, memory footprint, and code volume to prevent performance regressions on critical libraries. The primary goal of this check is to track and enforce performance standards for package import times across the repository, especially following our recent work on lazy loading and cold-start optimizations. By running this benchmark as a CI check with a defined dynamic differential failure threshold, we can programmatically prevent latency regressions in module initialization times before they are merged, ensuring downstream consumers aren't impacted by unexpectedly slow startup times. ## Changes Included * **GitHub Actions Workflow**: Created a new workflow (`.github/workflows/import-profiler.yml`) that triggers on PRs and merge groups. The workflow is pinned specifically to Python 3.15. * **Native CI Integration (No template bloat)**: Rather than polluting the central gapic-generator template (`noxfile.py.j2`) and forcing updates across 150+ packages, the CI script (`ci/run_single_test.sh`) natively handles the profiler. It automatically spins up a lightweight virtual environment, installs the target package, and runs the profiler. * **Dynamic Differential Checks**: Enhanced `ci/run_single_test.sh` to checkout `HEAD^1` (the main branch), generate a baseline CSV profile, and then diff it against the PR branch. If the Median (P50) import time of the PR degrades by >100ms compared to the baseline, the CI check will fail. *(Note: Using Median instead of P99 ensures stability against intermittent CPU spikes on GitHub Action runners).* * **Safety Backstop**: The script still enforces an absolute hard-failure backstop of 5000ms for extreme regressions. * **Conditional Execution & Graceful Skips**: The pipeline verifies if a valid `setup.py` exists before attempting to profile, gracefully skipping directories that are not valid Python packages. ## Developer Interactions If a developer fails this CI check due to an import latency regression, they can reproduce and debug it locally by running the profiler script with the `--cprofile` flag (`python scripts/import_profiler/profiler.py --package <their-package> --cprofile`). This will generate a cProfile stack trace breakdown of the import time, allowing them to pinpoint exactly which new dependency or module initialization is causing the latency spike. Related PRs * Builds upon the import profiler tool added in #17467 * Regression test proving the CI catches regressions: #17690 --------- Co-authored-by: Chalmer Lowe <chalmerlowe@google.com> Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>
Contributor
|
Closing as #17657 was merged |
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
This PR is a demonstration to verify that the CI import-profiler correctly catches performance regressions.
It was opened against the test-lazy-modules-base branch, which simulates a package with fast, lazy-loaded imports (0ms). In this PR, I have restored the 4,300 lines of heavy static imports to google-cloud-compute/init.py.
This effectively simulates the scenario where a PR "removes" lazy loading from a package, causing a massive latency regression. The CI import-profiler check should flag this regression and fail the presubmit, as requested by reviewers.