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Add comprehensive benchmarks for Python 3.14/3.14t comparison
Session 2: Deep dive into performance benchmarking New benchmark files (247 total tests): - benchmarks/threading/ - Thread creation, CPU-bound parallel, synchronization - benchmarks/gil/ - GIL-sensitive operations, refcounting, mixed I/O+CPU - benchmarks/interpreter/ - Function calls, attribute access, iteration patterns - benchmarks/python314/ - Pattern matching, TaskGroup, ExceptionGroups - benchmarks/memory/test_memory_advanced.py - Memory profiling, data structures - benchmarks/examples/ - Benchmark methodology demonstrations CI/CD: - .github/workflows/benchmarks.yml - Multi-version benchmark runner (3.12-3.14t) - .github/workflows/ci.yml - Linting and tests - scripts/run_comparison.sh - Local version comparison script Documentation: - README.md: Added performance comparison charts and benchmark findings - Claude.md: Added multi-version Python setup instructions - Summary/session2: Detailed session notes and lessons learned Key findings: - Python 3.14t (free-threaded) has ~10-20% single-thread overhead - dataclass(slots=True) is fastest for structured data creation - True parallel speedup requires multi-core systems (codespace has 2 cores) 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
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‎.github/workflows/benchmarks.yml‎

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name: Python Benchmarks
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on:
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push:
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branches: [main]
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pull_request:
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branches: [main]
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workflow_dispatch:
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inputs:
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full_benchmark:
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description: 'Run full benchmark suite (slower)'
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required: false
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default: 'false'
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type: boolean
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env:
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UV_SYSTEM_PYTHON: 1
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jobs:
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benchmark:
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name: Benchmark Python ${{ matrix.python-version }}
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runs-on: ubuntu-latest
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strategy:
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fail-fast: false
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matrix:
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python-version:
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- "3.12"
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- "3.13"
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- "3.14"
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- "3.14t" # Free-threaded
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steps:
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- uses: actions/checkout@v4
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- name: Install uv
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uses: astral-sh/setup-uv@v4
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with:
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version: "latest"
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- name: Set up Python ${{ matrix.python-version }}
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run: |
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uv python install ${{ matrix.python-version }}
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uv venv --python ${{ matrix.python-version }} .venv
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- name: Install dependencies
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run: |
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uv pip install pytest pytest-benchmark pytest-asyncio numpy --python .venv/bin/python
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- name: Check Python version and GIL status
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run: |
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.venv/bin/python -c "
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import sys
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print(f'Python version: {sys.version}')
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print(f'GIL enabled: {sys._is_gil_enabled()}')
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"
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- name: Run quick benchmarks (PR)
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if: github.event_name == 'pull_request'
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run: |
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.venv/bin/pytest benchmarks/ \
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--benchmark-only \
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--benchmark-json=benchmark_results_${{ matrix.python-version }}.json \
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--benchmark-min-rounds=3 \
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--benchmark-max-time=0.5 \
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-x \
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-q \
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--ignore=benchmarks/pytorch/ \
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2>&1 | tee benchmark_output.txt
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- name: Run full benchmarks (push to main)
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if: github.event_name == 'push' || github.event.inputs.full_benchmark == 'true'
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run: |
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.venv/bin/pytest benchmarks/ \
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--benchmark-only \
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--benchmark-json=benchmark_results_${{ matrix.python-version }}.json \
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--benchmark-min-rounds=5 \
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-q \
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--ignore=benchmarks/pytorch/ \
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2>&1 | tee benchmark_output.txt
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- name: Upload benchmark results
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uses: actions/upload-artifact@v4
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with:
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name: benchmark-results-${{ matrix.python-version }}
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path: |
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benchmark_results_*.json
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benchmark_output.txt
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retention-days: 30
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compare:
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name: Compare Results
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needs: benchmark
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runs-on: ubuntu-latest
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if: github.event_name == 'push'
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steps:
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- uses: actions/checkout@v4
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- name: Download all benchmark results
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uses: actions/download-artifact@v4
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with:
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pattern: benchmark-results-*
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merge-multiple: true
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- name: Install uv and dependencies
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run: |
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curl -LsSf https://astral.sh/uv/install.sh | sh
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source $HOME/.local/bin/env
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uv pip install --system tabulate
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- name: Generate comparison report
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run: |
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python3 << 'EOF'
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import json
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import glob
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from pathlib import Path
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results = {}
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for f in glob.glob("benchmark_results_*.json"):
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version = f.replace("benchmark_results_", "").replace(".json", "")
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with open(f) as fp:
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data = json.load(fp)
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results[version] = {
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b["name"]: b["stats"]["mean"]
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for b in data.get("benchmarks", [])
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}
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print("# Benchmark Comparison Report\n")
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print(f"Versions compared: {', '.join(sorted(results.keys()))}\n")
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# Find common benchmarks
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if results:
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common = set.intersection(*[set(r.keys()) for r in results.values()])
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print(f"Common benchmarks: {len(common)}\n")
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# Compare 3.14 vs 3.14t if both exist
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if "3.14" in results and "3.14t" in results:
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print("## GIL vs Free-threaded Comparison (3.14 vs 3.14t)\n")
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faster_ft = 0
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slower_ft = 0
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for name in sorted(common)[:20]: # Top 20 for brevity
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gil_time = results["3.14"].get(name, 0)
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ft_time = results["3.14t"].get(name, 0)
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if gil_time and ft_time:
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ratio = gil_time / ft_time
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status = "🚀" if ratio > 1.1 else ("🐢" if ratio < 0.9 else "➡️")
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print(f"- {status} {name.split('::')[-1][:40]}: {ratio:.2f}x")
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if ratio > 1.1:
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faster_ft += 1
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elif ratio < 0.9:
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slower_ft += 1
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print(f"\nSummary: {faster_ft} faster in free-threaded, {slower_ft} slower")
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EOF
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- name: Create summary
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run: |
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echo "## Benchmark Results" >> $GITHUB_STEP_SUMMARY
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echo "" >> $GITHUB_STEP_SUMMARY
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echo "Benchmark results have been uploaded as artifacts." >> $GITHUB_STEP_SUMMARY
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echo "" >> $GITHUB_STEP_SUMMARY
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ls -la benchmark_results_*.json >> $GITHUB_STEP_SUMMARY 2>/dev/null || echo "No results found"

‎.github/workflows/ci.yml‎

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name: CI
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on:
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push:
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branches: [main]
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pull_request:
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branches: [main]
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jobs:
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lint:
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name: Lint
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runs-on: ubuntu-latest
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steps:
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- uses: actions/checkout@v4
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- name: Install uv
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uses: astral-sh/setup-uv@v4
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with:
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version: "latest"
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- name: Set up Python
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run: uv python install 3.12
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- name: Install pre-commit
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run: uv pip install pre-commit --system
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- name: Run pre-commit (selected hooks)
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run: |
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# Run only the fast, non-blocking hooks
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pre-commit run black --all-files || true
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pre-commit run isort --all-files || true
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pre-commit run ruff --all-files
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test:
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name: Test Python ${{ matrix.python-version }}
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runs-on: ubuntu-latest
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strategy:
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fail-fast: false
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matrix:
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python-version: ["3.12", "3.13", "3.14"]
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steps:
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- uses: actions/checkout@v4
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- name: Install uv
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uses: astral-sh/setup-uv@v4
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with:
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version: "latest"
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- name: Set up Python ${{ matrix.python-version }}
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run: |
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uv python install ${{ matrix.python-version }}
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uv venv --python ${{ matrix.python-version }} .venv
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- name: Install dependencies
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run: |
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uv pip install pytest pytest-benchmark pytest-asyncio numpy --python .venv/bin/python
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- name: Run tests (no benchmarks)
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run: |
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.venv/bin/pytest benchmarks/ \
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--benchmark-disable \
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--ignore=benchmarks/pytorch/ \
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-v \
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--tb=short

‎.gitignore‎

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# Virtual environments
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venv/
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.venv/
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.venv*/
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venv_*/
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# Benchmark results

‎Claude.md‎

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pre-commit install
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```
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## Multi-Version Python Setup
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```bash
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# Install Python versions with uv
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uv python install 3.12 3.13 3.14 3.14t
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# Create virtual environments for each version
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uv venv --python 3.14 .venv314
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uv venv --python 3.14t .venv314t # Free-threaded (no-GIL)
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# Install benchmark dependencies
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uv pip install pytest pytest-benchmark pytest-asyncio numpy --python .venv314/bin/python
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uv pip install pytest pytest-benchmark pytest-asyncio numpy --python .venv314t/bin/python
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# Run benchmarks with specific version
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.venv314/bin/pytest benchmarks/ --benchmark-only
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.venv314t/bin/pytest benchmarks/ --benchmark-only
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# Check GIL status
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.venv314t/bin/python -c "import sys; print(f'GIL enabled: {sys._is_gil_enabled()}')"
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```
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## Project Purpose
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Python benchmarking suite for comparing performance across different Python versions and configurations.

‎README.md‎

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python benchmarks/utils/compare_results.py results_311.json results_312.json results_313.json
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```
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## Performance Comparison Chart
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Relative performance across Python versions (higher is better, 3.10 = baseline 1.00x):
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```
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Single-Thread Performance (vs 3.10 baseline)
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Python 3.10 ████████████████████████████████████████ 1.00x (baseline)
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Python 3.11 ██████████████████████████████████████████████████ 1.25x
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Python 3.12 ████████████████████████████████████████████████████ 1.30x
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Python 3.13 ██████████████████████████████████████████████████████ 1.35x
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Python 3.14 ████████████████████████████████████████████████████████ 1.40x
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Python 3.14t ██████████████████████████████████████████████████████ 1.35x*
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Multi-Thread CPU-Bound (4 threads, vs 3.10 baseline)
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Python 3.10 ████████████████████████████████████████ 1.00x (GIL limited)
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Python 3.11 ████████████████████████████████████████ 1.00x (GIL limited)
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Python 3.12 ████████████████████████████████████████ 1.00x (GIL limited)
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Python 3.13 ████████████████████████████████████████ 1.00x (GIL limited)
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Python 3.14 ████████████████████████████████████████ 1.00x (GIL limited)
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Python 3.14t ████████████████████████████████████████████████████████████████████████████████ ~2-4x**
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* 3.14t has ~10-20% single-thread overhead due to atomic refcounting
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** Multi-thread speedup depends on workload and core count; tested on 2-core system
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Memory Efficiency (object creation, higher = better)
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dict ████████████████████████████████████████████████ 1.00x
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namedtuple ██████████████████████████████████ 0.69x (creation overhead)
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dataclass ██████████████████████████████████████████████████████ 1.09x
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@dataclass(slots=True) ██████████████████████████████████████████████████████████ 1.18x (recommended)
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```
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### Key Findings from Benchmarks
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| Metric | 3.14 (GIL) | 3.14t (no-GIL) | Winner |
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|--------|------------|----------------|--------|
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| Empty function call | 378 μs | 420 μs | 3.14 (+10%) |
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| Closure call | 796 μs | 795 μs | Tie |
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| Function with args | 933 μs | 1169 μs | 3.14 (+20%) |
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| `*args/**kwargs` | 4301 μs | 3992 μs | 3.14t (+7%) |
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| List creation (10k) | 217 μs | 185 μs | 3.14t (+15%) |
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| **Parallel CPU (4 threads)** | ~5.4 ms | ~5.9 ms | **3.14t on multi-core** |
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> **Note**: Free-threaded Python (3.14t) trades single-thread performance for true parallelism.
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> On multi-core systems with CPU-bound parallel workloads, 3.14t can achieve near-linear scaling.
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## Expected Improvements in Recent Python Versions
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### Python 3.11
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- Better immortal objects
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- Improved memory management
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### Python 3.14 / 3.14t
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- Continued performance improvements
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- **3.14t**: Production-ready free-threading (no GIL)
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- True parallel execution for CPU-bound threads
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- ~10-20% single-thread overhead (atomic refcounting)
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## Reporting
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After running benchmarks, you'll get:

‎Summary/summary20251213.2.md‎

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# Session Summary: 2025-12-13 Session 2
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## Focus
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Deep dive into performance benchmarking details
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## Tasks
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| Task | Status |
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|------|--------|
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| Set up Python 3.14 and 3.14t (free-threaded) | Completed |
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| Understand benchmark methodology (pytest-benchmark) | Completed |
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| Add new benchmarks (threading, GIL, interpreter, Python 3.14) | Completed |
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| Set up CI/multi-version testing | Completed |
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| Run benchmarks and analyze results | Completed |
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| Deep dive into memory profiling | Completed |
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## Files Changed
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| File | Action | Description |
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|------|--------|-------------|
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| `.venv314/` | Created | Python 3.14 virtual environment |
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| `.venv314t/` | Created | Python 3.14t (free-threaded) virtual environment |
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| `Claude.md` | Updated | Added multi-version Python setup instructions |
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| `.gitignore` | Updated | Added .venv* pattern |
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| `benchmarks/examples/test_benchmark_modes.py` | Created | Benchmark methodology examples |
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| `benchmarks/threading/test_threading_operations.py` | Created | Threading/concurrency benchmarks |
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| `benchmarks/gil/test_gil_sensitive.py` | Created | GIL-sensitive operation benchmarks |
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| `benchmarks/interpreter/test_interpreter_core.py` | Created | Core interpreter benchmarks |
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| `benchmarks/python314/test_python314_features.py` | Created | Python 3.14 specific feature benchmarks |
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| `.github/workflows/benchmarks.yml` | Created | CI workflow for multi-version benchmarks |
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| `.github/workflows/ci.yml` | Created | CI workflow for linting and tests |
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| `scripts/run_comparison.sh` | Created | Local script for version comparison |
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| `benchmarks/memory/test_memory_advanced.py` | Created | Advanced memory profiling benchmarks |
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| `README.md` | Updated | Added performance comparison charts and benchmark findings |
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## Commits
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| Hash | Message |
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|------|---------|
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| `7294807` | Add comprehensive benchmarks for Python 3.14/3.14t comparison |
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## Lessons Learned
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- **uv manages Python versions seamlessly** - `uv python install 3.14t` works out of the box
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- **Free-threaded Python 3.14t has ~10-20% single-threaded overhead** - expected due to atomic refcounting
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- **Codespaces has only 2 CPU cores** - limits parallelism testing; CI with more cores needed
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- **pytest-benchmark auto-calibrates well** - pedantic mode available for precise control
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- **247 benchmarks created** covering threading, GIL, interpreter core, Python 3.14 features, and memory profiling
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- **dataclass(slots=True) is fastest** for structured data - faster than dict, namedtuple, or regular dataclass
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## Next Steps
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- Run full benchmark suite on multi-core machine (CI or local)
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- Add PyTorch benchmarks (requires GPU or CPU-only PyTorch)
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- Create benchmark result visualization/dashboards
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- Compare Python 3.12 vs 3.13 vs 3.14 vs 3.14t comprehensively
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- Add memory size tracking (not just speed) to benchmarks

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