Add debug logging for threading and parallelization dec… #3
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…isions Adds debug logging across Rust and Python components to help diagnose threading behavior and parallelization decisions. Includes logging for: - Rust threading decisions in getenv_use_multiple_threads() - PassManager parallel execution choices and process counts - SABRE layout trial count configuration - parallel_map execution paths and results Co-Authored with the help of: Claude
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Pull Request Overview
Adds debug logging across Python and Rust components to help diagnose threading and parallelization decisions.
- Python: Injected
logger.debugstatements inshould_run_in_parallel,parallel_map, SABRE trial count, and PassManager execution paths. - Rust: Emits threading decision to stderr when
QISKIT_DEBUG_THREADINGis set.
Reviewed Changes
Copilot reviewed 4 out of 4 changed files in this pull request and generated 4 comments.
| File | Description |
|---|---|
| qiskit/utils/parallel.py | Added logging import, logger setup, and debug statements around parallel decisions and execution. |
| qiskit/transpiler/preset_passmanagers/builtin_plugins.py | Added debug logging in _get_trial_count for SABRE threading trials. |
| qiskit/passmanager/passmanager.py | Added debug logs in callback_func for serial vs parallel PassManager runs. |
| crates/accelerate/src/lib.rs | Added Rust debug printing under QISKIT_DEBUG_THREADING environment variable. |
Comments suppressed due to low confidence (1)
qiskit/utils/parallel.py:197
- The environment variable QISKIT_IN_PARALLEL is only reset in the KeyboardInterrupt branch, so other exceptions leave it set to TRUE. Consider moving the reset into a finally block to ensure it's always restored.
os.environ["QISKIT_IN_PARALLEL"] = "FALSE"
| @@ -239,6 +244,9 @@ def callback_func(**kwargs): | |||
| del callback | |||
| del kwargs | |||
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| logger.debug("PassManager running %d programs in parallel with %d processes", | |||
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The serial execution branch assigns to out but lacks a return, so execution always falls through to the parallel path. Add a return statement inside the if-block to avoid unintended parallel runs.
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| // Log threading decision if debug logging is enabled | ||
| if env::var("QISKIT_DEBUG_THREADING").is_ok() { | ||
| eprintln!( |
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[nitpick] Using eprintln! for debug output is inconsistent with typical Rust logging practices. Consider using the log crate to emit debug-level messages and integrate with existing logging infrastructure.
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Co-authored-by: Copilot <[email protected]>
…isions
Adds debug logging across Rust and Python components to help diagnose threading behavior and parallelization decisions. Includes logging for:
Co-Authored with the help of: Claude
Summary
Details and comments