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perf(standalone): detect job completion by polling the process handle - #1053
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Navigate logical layers of code changes, visualize relationships, and explore their blast radius. 🧰 Additional context used📚 Code guidelines (1)No actionable comments were generated in the recent review. 🎉 ℹ️ Recent review info⚙️ Run configurationConfiguration used: Repository: NVIDIA/cloudai/.coderabbit.yaml Review profile: ASSERTIVE Plan: Enterprise Run ID: 📒 Files selected for processing (3)
Included review availability: This review used your included allowance. Your plan provides up to 12 included reviews per hour; 11 remain after this review. 📝 WalkthroughWalkthroughStandalone jobs now retain launched process handles. Running-status checks poll those handles or probe job IDs with signal 0. Tests cover both paths and avoid shell-based status checks. ChangesStandalone process tracking
Priority: ⬇️ Low Estimated code review effort: 2 (Simple) | ~10 minutes Change: Bug fix Merge Risk: ⚪ Minimal · up to Standalone job completion now polls the process handle, with a safe signal-0 fallback when no handle exists. The earlier PID 0 and permission-error concerns are fixed, and no open issues remain. 🚥 Pre-merge checks | ✅ 4✅ Passed checks (4 passed)
✨ Finishing Touches📝 Generate docstrings
🧪 Generate unit tests (beta)
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Inline comments:
In `@src/cloudai/systems/standalone/standalone_system.py`:
- Line 66: Update StandaloneSystem.is_job_running() to convert the no-handle job
ID to an integer, return False with the existing debug logging when the PID is
non-positive, and only call os.kill for positive PIDs. Extend the fallback tests
to cover IDs 0 and -1.
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src/cloudai/systems/standalone/standalone_job.pysrc/cloudai/systems/standalone/standalone_runner.pysrc/cloudai/systems/standalone/standalone_system.pytests/systems/standalone/test_system.py
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September 22, 2026 23:29
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- 🪄 Fix CodeRabbit comments on this PR
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Inline comments:
In `@src/cloudai/systems/standalone/standalone_system.py`:
- Line 67: Update the job-running status logic around os.kill in
is_job_completed so PermissionError is handled separately from
ProcessLookupError, TypeError, and ValueError; return True when PermissionError
occurs because the process exists but cannot be signaled, while preserving the
existing False behavior for the other exceptions.
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rutayan-nv
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Rebased onto main, six checks green, no open review threads. Ready for review. Two real bugs were fixed in the no-handle fallback since this was opened, both worth a look during review:
The copyright commit dropped out of the rebase because main had already bumped those files. |
podkidyshev
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Oct 1, 2026
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@rutayan-nv minor things spotted otherwise lgtm. resolve or reject and feel free to merge 👍 |
is_job_running shelled out to `ps -p <pid>` and matched the pid as a substring of the output. The runner already owns the Popen it launched and then discarded it, keeping only the pid, so the handle had to be rediscovered externally on every check. That check runs on every monitor tick. Each one spawns two processes, a shell and a ps, costing about 10 ms; measured on a proxy-model DSE run it fired roughly seven times per trial against ~25 ms of actual work. Polling the handle is a single syscall. StandaloneJob now carries the Popen for the process it represents, which is where the handle belongs: its lifetime is the job's, so there is no registry to keep in step and nothing to leak. The runner passes the object it was already creating. Two secondary defects go with it. `str(job.id) in stdout` matches the pid anywhere in ps output, including inside another column, so an unrelated process could read as the job still running. And a finished-but-unreaped child stays visible to ps as a zombie, which reads as running forever; poll() reaps it. A job with no handle -- dry run, or reconstructed from prior state -- falls back to probing with signal 0, which tests for the pid without delivering anything, and treats a non-numeric id as not running. Replaces test_is_job_running, which mocked CommandShell.execute and asserted the pid appeared in mocked ps stdout. That assertion described the implementation being removed and could not survive the change; it is substituted by tests that poll the handle, assert no subprocess is spawned, cover the fallback probe, and cover a non-numeric id. kill() still uses the shell and is left alone; routing it through the handle is a separate change.
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Summary
Checking whether a job finished no longer starts a new process.
flowchart TB subgraph Before["Before: ask by running a command"] direction LR A["is the job done?"] --> B["start a new 'ps' process"] B --> C["read its output"] end subgraph After["After: ask the handle we already hold"] direction LR D["is the job done?"] --> E["process handle"] end Before ~~~ AfterTo check whether a job had finished, cloudai ran the
pscommand, starting a whole new process just to ask about one. It now asks the process handle it already holds.is_job_runningshelled out tops -p <pid>and matched the pid as a substring of the output, while the runner already owned thePopenand threw it away. That check runs every monitor tick — two processes each, ~10 ms, roughly seven times per trial against ~25 ms of real work.StandaloneJobnow carries thePopen, so lifetime matches the job and there is no registry to leak.Two correctness bugs go with it:
str(job.id) in stdoutmatches the pid anywhere inpsoutput including another column, and an unreaped child stays visible as a zombie and reads as running forever.poll()reaps it. With no handle — dry run, or a job reconstructed from prior state — it falls back to a signal-0probe.Test Plan
Four new tests, including no subprocess spawned, asserted by patching
CommandShell.executeand requiring it uncalled. Revert to thepsshell-out → 5 fail.ruff,pyrightclean. Full suite 1980 passed, 5 skipped.Additional Notes
Replaces
test_is_job_running, whose assertion described the implementation being removed and could not survive the change.kill()still uses the shell — that one runs once, not every tick.