Slower to run some hooks (debug-statements, ruff) than pre-commit

### Summary

I’ve just taken prek for a spin and while the hook installation was faster (maybe 3-4x!), meaning overall run the first time (after wiping the cache dirs for level playing field) was faster, subsequent runs were slower (by about 0.5s - 1s) because somehow prek is slower to execute the hooks than pre-commit.

I presume this is worth a bug report given speed is prek’s primary goal, and hooks are likely going to be executed more often than they are installed (at least locally)

### Platform

Linux 5.15.0-125-generic x86_64 GNU/Linux

### Version

prek 0.2.5

### .pre-commit-config.yaml

<details><summary>Click to show</summary>

```
ci:
  autofix_commit_msg: "chore(pre-commit): autofix run"
  autoupdate_commit_msg: "chore(pre-commit): autoupdate hooks"

default_install_hook_types:
  - pre-commit
  - commit-msg

repos:
  - repo: https://github.com/compilerla/conventional-pre-commit
    rev: v4.2.0
    hooks:
      - id: conventional-pre-commit
        stages: [commit-msg]
        # args: [build, chore, ci, docs, feat, fix, perf, refactor, revert, style, test]
  - repo: https://github.com/pre-commit/pre-commit-hooks
    rev: v6.0.0
    hooks:
      - id: check-toml
      - id: check-yaml
        exclude: ^mkdocs.yml
      - id: debug-statements
      - id: end-of-file-fixer
      - id: name-tests-test
      - id: trailing-whitespace
  - repo: https://github.com/pappasam/toml-sort
    rev: v0.24.3
    hooks:
      - id: toml-sort-fix
  - repo: https://github.com/asottile/add-trailing-comma
    rev: v3.2.0
    hooks:
      - id: add-trailing-comma
  - repo: https://github.com/asottile/pyupgrade
    rev: v3.20.0
    hooks:
      - id: pyupgrade
        args: [--py310-plus]
  - repo: https://github.com/astral-sh/ruff-pre-commit
    rev: v0.13.3
    hooks:
      # Run the linter
      - id: ruff
        args: [--fix]
      # Run the formatter
      - id: ruff-format
```

</details>

### Log file

<details><summary>Click to show</summary>

```
2025-10-13T09:32:47.825851Z DEBUG prek: 0.2.5 (/home/louis/.local/bin/prek)
2025-10-13T09:32:48.062549Z DEBUG Git root: /home/louis/tmp/polars-permute-plugin
2025-10-13T09:32:48.062881Z DEBUG Found workspace root at `/home/louis/tmp/polars-permute-plugin`
2025-10-13T09:32:48.063043Z TRACE Include selectors: 
2025-10-13T09:32:48.063131Z TRACE Skip selectors: 
2025-10-13T09:32:48.102301Z DEBUG discover{store=Store { path: "/home/louis/.cache/prek" }
root="/home/louis/tmp/polars-permute-plugin" config=None refresh=false}: Loaded workspace from cache
2025-10-13T09:32:48.103186Z DEBUG discover{store=Store { path: "/home/louis/.cache/prek" }
root="/home/louis/tmp/polars-permute-plugin" config=None refresh=false}: Loading project
configuration path=.pre-commit-config.yaml
2025-10-13T09:32:48.107267Z TRACE discover{store=Store { path: "/home/louis/.cache/prek" }
root="/home/louis/tmp/polars-permute-plugin" config=None refresh=false}: close time.busy=43.7ms
time.idle=178µs
2025-10-13T09:32:48.108815Z TRACE Checking lock resource="store" path=/home/louis/.cache/prek/.lock
2025-10-13T09:32:48.108979Z DEBUG Acquired lock resource="store"
2025-10-13T09:32:48.124538Z DEBUG Hooks going to run: ["check-toml", "check-yaml",
"debug-statements", "end-of-file-fixer", "name-tests-test", "trailing-whitespace", "toml-sort-fix",
"add-trailing-comma", "pyupgrade", "ruff", "ruff-format"]
2025-10-13T09:32:48.125403Z DEBUG Checking health of installed hooks
2025-10-13T09:32:48.128111Z TRACE Executing
`/home/louis/.cache/prek/hooks/python-vtizewRRafdh8DCZpy67/bin/python -I -c import sys
print(f"{sys.version_info.major}.{sys.version_info.minor}.{sys.version_info.micro}")
print(sys.base_exec_prefix)
 [...]`
2025-10-13T09:32:48.154296Z TRACE Executing
`/home/louis/.cache/prek/hooks/python-pnR5Fl7LBdVfGJ6wApBn/bin/python -I -c import sys
print(f"{sys.version_info.major}.{sys.version_info.minor}.{sys.version_info.micro}")
print(sys.base_exec_prefix)
 [...]`
2025-10-13T09:32:48.154920Z TRACE Executing
`/home/louis/.cache/prek/hooks/python-lcxTSDMCHRxaiQJWjWsF/bin/python -I -c import sys
print(f"{sys.version_info.major}.{sys.version_info.minor}.{sys.version_info.micro}")
print(sys.base_exec_prefix)
 [...]`
2025-10-13T09:32:48.155404Z TRACE Executing
`/home/louis/.cache/prek/hooks/python-sNi6mT5pdthxSLXBnboE/bin/python -I -c import sys
print(f"{sys.version_info.major}.{sys.version_info.minor}.{sys.version_info.micro}")
print(sys.base_exec_prefix)
 [...]`
2025-10-13T09:32:48.232883Z TRACE Executing
`/home/louis/.cache/prek/hooks/python-mkiKwZtEtSB2XIgOma4s/bin/python -I -c import sys
print(f"{sys.version_info.major}.{sys.version_info.minor}.{sys.version_info.micro}")
print(sys.base_exec_prefix)
 [...]`
2025-10-13T09:32:48.256576Z DEBUG Found installed environment for hook `check-toml` at
`/home/louis/.cache/prek/hooks/python-sNi6mT5pdthxSLXBnboE`
2025-10-13T09:32:48.267917Z DEBUG Found installed environment for hook `check-yaml` at
`/home/louis/.cache/prek/hooks/python-sNi6mT5pdthxSLXBnboE`
2025-10-13T09:32:48.268083Z DEBUG Found installed environment for hook `debug-statements` at
`/home/louis/.cache/prek/hooks/python-sNi6mT5pdthxSLXBnboE`
2025-10-13T09:32:48.268180Z DEBUG Found installed environment for hook `end-of-file-fixer` at
`/home/louis/.cache/prek/hooks/python-sNi6mT5pdthxSLXBnboE`
2025-10-13T09:32:48.268326Z DEBUG Found installed environment for hook `name-tests-test` at
`/home/louis/.cache/prek/hooks/python-sNi6mT5pdthxSLXBnboE`
2025-10-13T09:32:48.268501Z DEBUG Found installed environment for hook `trailing-whitespace` at
`/home/louis/.cache/prek/hooks/python-sNi6mT5pdthxSLXBnboE`
2025-10-13T09:32:48.268649Z DEBUG Found installed environment for hook `toml-sort-fix` at
`/home/louis/.cache/prek/hooks/python-vtizewRRafdh8DCZpy67`
2025-10-13T09:32:48.268762Z DEBUG Found installed environment for hook `add-trailing-comma` at
`/home/louis/.cache/prek/hooks/python-pnR5Fl7LBdVfGJ6wApBn`
2025-10-13T09:32:48.269042Z DEBUG Found installed environment for hook `pyupgrade` at
`/home/louis/.cache/prek/hooks/python-mkiKwZtEtSB2XIgOma4s`
2025-10-13T09:32:48.269396Z DEBUG Found installed environment for hook `ruff` at
`/home/louis/.cache/prek/hooks/python-lcxTSDMCHRxaiQJWjWsF`
2025-10-13T09:32:48.269682Z DEBUG Found installed environment for hook `ruff-format` at
`/home/louis/.cache/prek/hooks/python-lcxTSDMCHRxaiQJWjWsF`
2025-10-13T09:32:48.269916Z TRACE Released lock path=/home/louis/.cache/prek/.lock
2025-10-13T09:32:48.270180Z TRACE Executing `cd /home/louis/tmp/polars-permute-plugin &&
/usr/bin/git ls-files -z -- /home/louis/tmp/polars-permute-plugin`
2025-10-13T09:32:48.273014Z DEBUG All files in the workspace: 18
2025-10-13T09:32:48.273416Z TRACE Executing `/usr/bin/git diff --
/home/louis/tmp/polars-permute-plugin`
2025-10-13T09:32:48.276875Z TRACE Files for project `.` after filtered: 18
2025-10-13T09:32:48.277116Z TRACE Files for hook `check-toml` after filtered: 1
2025-10-13T09:32:48.277224Z DEBUG Running builtin hook: check-toml
2025-10-13T09:32:48.277392Z TRACE Executing `/usr/bin/git diff --
/home/louis/tmp/polars-permute-plugin`
2025-10-13T09:32:48.281031Z TRACE Files for hook `check-yaml` after filtered: 1
2025-10-13T09:32:48.281122Z DEBUG Running builtin hook: check-yaml
2025-10-13T09:32:48.281155Z TRACE Resolved command: check-yaml
2025-10-13T09:32:48.281604Z TRACE Executing `/usr/bin/git diff --
/home/louis/tmp/polars-permute-plugin`
2025-10-13T09:32:48.284745Z TRACE Files for hook `debug-statements` after filtered: 11
2025-10-13T09:32:48.284910Z TRACE Resolved command:
/home/louis/.cache/prek/hooks/python-sNi6mT5pdthxSLXBnboE/bin/debug-statement-hook
2025-10-13T09:32:48.285013Z TRACE Found shebang:
["/home/louis/.cache/prek/hooks/python-sNi6mT5pdthxSLXBnboE/bin/python3"]
2025-10-13T09:32:48.285126Z TRACE Resolved interpreter:
/home/louis/.cache/prek/hooks/python-sNi6mT5pdthxSLXBnboE/bin/python3
2025-10-13T09:32:48.285182Z TRACE Running debug-statements total_files=11 concurrency=4
2025-10-13T09:32:48.285396Z TRACE Executing `cd /home/louis/tmp/polars-permute-plugin &&
/home/louis/.cache/prek/hooks/python-sNi6mT5pdthxSLXBnboE/bin/python3
/home/louis/.cache/prek/hooks/python-sNi6mT5pdthxSLXBnboE/bin/debug-statement-hook
tests/basic_permutations_test.py [...]`
2025-10-13T09:32:48.286780Z TRACE Executing `cd /home/louis/tmp/polars-permute-plugin &&
/home/louis/.cache/prek/hooks/python-sNi6mT5pdthxSLXBnboE/bin/python3
/home/louis/.cache/prek/hooks/python-sNi6mT5pdthxSLXBnboE/bin/debug-statement-hook
tests/expressions_test.py [...]`
2025-10-13T09:32:48.290000Z TRACE Executing `cd /home/louis/tmp/polars-permute-plugin &&
/home/louis/.cache/prek/hooks/python-sNi6mT5pdthxSLXBnboE/bin/python3
/home/louis/.cache/prek/hooks/python-sNi6mT5pdthxSLXBnboE/bin/debug-statement-hook
tests/data_integrity_test.py [...]`
2025-10-13T09:32:48.800182Z TRACE Executing `/usr/bin/git diff --
/home/louis/tmp/polars-permute-plugin`
2025-10-13T09:32:48.803527Z TRACE Files for hook `end-of-file-fixer` after filtered: 18
2025-10-13T09:32:48.803605Z DEBUG Running builtin hook: end-of-file-fixer
2025-10-13T09:32:48.805570Z TRACE Executing `/usr/bin/git diff --
/home/louis/tmp/polars-permute-plugin`
2025-10-13T09:32:48.816701Z TRACE Files for hook `name-tests-test` after filtered: 10
2025-10-13T09:32:48.816835Z TRACE Resolved command:
/home/louis/.cache/prek/hooks/python-sNi6mT5pdthxSLXBnboE/bin/name-tests-test
2025-10-13T09:32:48.816888Z TRACE Found shebang:
["/home/louis/.cache/prek/hooks/python-sNi6mT5pdthxSLXBnboE/bin/python3"]
2025-10-13T09:32:48.816965Z TRACE Resolved interpreter:
/home/louis/.cache/prek/hooks/python-sNi6mT5pdthxSLXBnboE/bin/python3
2025-10-13T09:32:48.816997Z TRACE Running name-tests-test total_files=10 concurrency=4
2025-10-13T09:32:48.817142Z TRACE Executing `cd /home/louis/tmp/polars-permute-plugin &&
/home/louis/.cache/prek/hooks/python-sNi6mT5pdthxSLXBnboE/bin/python3
/home/louis/.cache/prek/hooks/python-sNi6mT5pdthxSLXBnboE/bin/name-tests-test
tests/before_after_test.py [...]`
2025-10-13T09:32:48.819924Z TRACE Executing `cd /home/louis/tmp/polars-permute-plugin &&
/home/louis/.cache/prek/hooks/python-sNi6mT5pdthxSLXBnboE/bin/python3
/home/louis/.cache/prek/hooks/python-sNi6mT5pdthxSLXBnboE/bin/name-tests-test
tests/multiple_columns_test.py [...]`
2025-10-13T09:32:48.821127Z TRACE Executing `cd /home/louis/tmp/polars-permute-plugin &&
/home/louis/.cache/prek/hooks/python-sNi6mT5pdthxSLXBnboE/bin/python3
/home/louis/.cache/prek/hooks/python-sNi6mT5pdthxSLXBnboE/bin/name-tests-test
tests/edge_cases_test.py [...]`
2025-10-13T09:32:49.261008Z TRACE Executing `/usr/bin/git diff --
/home/louis/tmp/polars-permute-plugin`
2025-10-13T09:32:49.264338Z TRACE Files for hook `trailing-whitespace` after filtered: 18
2025-10-13T09:32:49.264404Z DEBUG Running builtin hook: trailing-whitespace
2025-10-13T09:32:49.264442Z TRACE Resolved command: trailing-whitespace-fixer
2025-10-13T09:32:49.266841Z TRACE Executing `/usr/bin/git diff --
/home/louis/tmp/polars-permute-plugin`
2025-10-13T09:32:49.270750Z TRACE Files for hook `toml-sort-fix` after filtered: 1
2025-10-13T09:32:49.271250Z TRACE Resolved command:
/home/louis/.cache/prek/hooks/python-vtizewRRafdh8DCZpy67/bin/toml-sort
2025-10-13T09:32:49.271451Z TRACE Found shebang:
["/home/louis/.cache/prek/hooks/python-vtizewRRafdh8DCZpy67/bin/python3"]
2025-10-13T09:32:49.271779Z TRACE Resolved interpreter:
/home/louis/.cache/prek/hooks/python-vtizewRRafdh8DCZpy67/bin/python3
2025-10-13T09:32:49.271899Z TRACE Running toml-sort-fix total_files=1 concurrency=4
2025-10-13T09:32:49.272432Z TRACE Executing `cd /home/louis/tmp/polars-permute-plugin &&
/home/louis/.cache/prek/hooks/python-vtizewRRafdh8DCZpy67/bin/python3
/home/louis/.cache/prek/hooks/python-vtizewRRafdh8DCZpy67/bin/toml-sort --in-place pyproject.toml`
2025-10-13T09:32:49.520589Z TRACE Executing `/usr/bin/git diff --
/home/louis/tmp/polars-permute-plugin`
2025-10-13T09:32:49.523985Z TRACE Files for hook `add-trailing-comma` after filtered: 11
2025-10-13T09:32:49.524119Z TRACE Resolved command:
/home/louis/.cache/prek/hooks/python-pnR5Fl7LBdVfGJ6wApBn/bin/add-trailing-comma
2025-10-13T09:32:49.524174Z TRACE Found shebang:
["/home/louis/.cache/prek/hooks/python-pnR5Fl7LBdVfGJ6wApBn/bin/python3"]
2025-10-13T09:32:49.524253Z TRACE Resolved interpreter:
/home/louis/.cache/prek/hooks/python-pnR5Fl7LBdVfGJ6wApBn/bin/python3
2025-10-13T09:32:49.524286Z TRACE Running add-trailing-comma total_files=11 concurrency=4
2025-10-13T09:32:49.524437Z TRACE Executing `cd /home/louis/tmp/polars-permute-plugin &&
/home/louis/.cache/prek/hooks/python-pnR5Fl7LBdVfGJ6wApBn/bin/python3
/home/louis/.cache/prek/hooks/python-pnR5Fl7LBdVfGJ6wApBn/bin/add-trailing-comma
tests/basic_permutations_test.py [...]`
2025-10-13T09:32:49.525769Z TRACE Executing `cd /home/louis/tmp/polars-permute-plugin &&
/home/louis/.cache/prek/hooks/python-pnR5Fl7LBdVfGJ6wApBn/bin/python3
/home/louis/.cache/prek/hooks/python-pnR5Fl7LBdVfGJ6wApBn/bin/add-trailing-comma
tests/expressions_test.py [...]`
2025-10-13T09:32:49.527143Z TRACE Executing `cd /home/louis/tmp/polars-permute-plugin &&
/home/louis/.cache/prek/hooks/python-pnR5Fl7LBdVfGJ6wApBn/bin/python3
/home/louis/.cache/prek/hooks/python-pnR5Fl7LBdVfGJ6wApBn/bin/add-trailing-comma
tests/data_integrity_test.py [...]`
2025-10-13T09:32:50.122101Z TRACE Executing `/usr/bin/git diff --
/home/louis/tmp/polars-permute-plugin`
2025-10-13T09:32:50.125387Z TRACE Files for hook `pyupgrade` after filtered: 11
2025-10-13T09:32:50.125532Z TRACE Resolved command:
/home/louis/.cache/prek/hooks/python-mkiKwZtEtSB2XIgOma4s/bin/pyupgrade
2025-10-13T09:32:50.125594Z TRACE Found shebang:
["/home/louis/.cache/prek/hooks/python-mkiKwZtEtSB2XIgOma4s/bin/python3"]
2025-10-13T09:32:50.125671Z TRACE Resolved interpreter:
/home/louis/.cache/prek/hooks/python-mkiKwZtEtSB2XIgOma4s/bin/python3
2025-10-13T09:32:50.125703Z TRACE Running pyupgrade total_files=11 concurrency=4
2025-10-13T09:32:50.125849Z TRACE Executing `cd /home/louis/tmp/polars-permute-plugin &&
/home/louis/.cache/prek/hooks/python-mkiKwZtEtSB2XIgOma4s/bin/python3
/home/louis/.cache/prek/hooks/python-mkiKwZtEtSB2XIgOma4s/bin/pyupgrade --py310-plus
tests/basic_permutations_test.py [...]`
2025-10-13T09:32:50.127313Z TRACE Executing `cd /home/louis/tmp/polars-permute-plugin &&
/home/louis/.cache/prek/hooks/python-mkiKwZtEtSB2XIgOma4s/bin/python3
/home/louis/.cache/prek/hooks/python-mkiKwZtEtSB2XIgOma4s/bin/pyupgrade --py310-plus
tests/expressions_test.py [...]`
2025-10-13T09:32:50.128777Z TRACE Executing `cd /home/louis/tmp/polars-permute-plugin &&
/home/louis/.cache/prek/hooks/python-mkiKwZtEtSB2XIgOma4s/bin/python3
/home/louis/.cache/prek/hooks/python-mkiKwZtEtSB2XIgOma4s/bin/pyupgrade --py310-plus
tests/data_integrity_test.py [...]`
2025-10-13T09:32:51.004579Z TRACE Executing `/usr/bin/git diff --
/home/louis/tmp/polars-permute-plugin`
2025-10-13T09:32:51.007888Z TRACE Files for hook `ruff` after filtered: 11
2025-10-13T09:32:51.008015Z TRACE Resolved command:
/home/louis/.cache/prek/hooks/python-lcxTSDMCHRxaiQJWjWsF/bin/ruff
2025-10-13T09:32:51.008081Z TRACE Running ruff total_files=11 concurrency=1
2025-10-13T09:32:51.008218Z TRACE Executing `cd /home/louis/tmp/polars-permute-plugin &&
/home/louis/.cache/prek/hooks/python-lcxTSDMCHRxaiQJWjWsF/bin/ruff check --force-exclude --fix
tests/basic_permutations_test.py tests/shift_operations_test.py tests/conftest.py [...]`
2025-10-13T09:32:51.369452Z TRACE Executing `/usr/bin/git diff --
/home/louis/tmp/polars-permute-plugin`
2025-10-13T09:32:51.373068Z TRACE Files for hook `ruff-format` after filtered: 11
2025-10-13T09:32:51.373201Z TRACE Resolved command:
/home/louis/.cache/prek/hooks/python-lcxTSDMCHRxaiQJWjWsF/bin/ruff
2025-10-13T09:32:51.373275Z TRACE Running ruff-format total_files=11 concurrency=1
2025-10-13T09:32:51.373420Z TRACE Executing `cd /home/louis/tmp/polars-permute-plugin &&
/home/louis/.cache/prek/hooks/python-lcxTSDMCHRxaiQJWjWsF/bin/ruff format --force-exclude
tests/basic_permutations_test.py tests/shift_operations_test.py tests/conftest.py [...]`
2025-10-13T09:32:51.386119Z TRACE Executing `/usr/bin/git diff --
/home/louis/tmp/polars-permute-plugin`
```

</details>

For what it's worth here is Claude Sonnet's asseessment of the logs' timing:

---

Looking at the debug logs, I can identify where `prek` is spending its time compared to
`pre-commit`. The main performance bottlenecks are:

## Time Distribution Analysis

From the timestamps in the logs, here's where the time is going:

1. **Health checking of installed hooks** (~108ms)
   - Lines show multiple Python version checks being executed sequentially
   - 5 separate health checks running Python with `-I -c` to verify versions
   - This happens at `09:32:48.128` to `09:32:48.256`

2. **Serial hook execution** (largest time sink)
   - **debug-statements**: ~515ms (09:32:48.285 → 09:32:48.800)
   - **name-tests-test**: ~444ms (09:32:48.817 → 09:32:49.261)
   - **toml-sort-fix**: ~249ms (09:32:49.272 → 09:32:49.520)
   - **add-trailing-comma**: ~597ms (09:32:49.524 → 09:32:50.122)
   - **pyupgrade**: ~879ms (09:32:50.125 → 09:32:51.004)
   - **ruff check**: ~361ms (09:32:51.008 → 09:32:51.369)

3. **Multiple `git diff` calls** 
   - Running `git diff` before every hook (~10 times total)
   - Each takes ~3-4ms, but adds up

## Why It's Slower

The logs show `concurrency=4` for several hooks, but you're still seeing significant serial
execution time. The likely issues are:

1. **Hook health checking overhead** - pre-commit likely caches this better or skips it
2. **Git diff being called repeatedly** - once before each hook instead of once upfront
3. **Process spawning overhead** - each hook execution involves spawning Python processes
4. **Possible inefficient parallelization** - despite `concurrency=4`, hooks may not be batching
   files optimally

## Quick Wins

To speed this up, `prek` could:
- Cache health check results more aggressively
- Run `git diff` once and reuse results
- Batch file processing more efficiently within hooks
- Consider running independent hooks in parallel (e.g., `check-toml` and `check-yaml` could run
  simultaneously)

The total runtime is ~3.5 seconds, with most time spent in Python tool execution (pyupgrade,
add-trailing-comma, etc.) rather than in prek's core logic.

---

and its comparison to pre-commit:

---

Wow, that's a significant difference! Let me compare:

## Comparison

| Hook | pre-commit | prek | Difference |
|------|-----------|------|------------|
| check-toml | 0.19s | ~instant | - |
| check-yaml | 0.38s | ~instant | - |
| debug-statements | 0.10s | 0.52s | **5.2x slower** |
| end-of-file-fixer | 0.24s | ~instant | - |
| name-tests-test | 0.11s | 0.44s | **4x slower** |
| trailing-whitespace | 0.11s | ~instant | - |
| toml-sort-fix | 0.25s | 0.25s | same |
| add-trailing-comma | 0.42s | 0.60s | 1.4x slower |
| pyupgrade | 0.49s | 0.88s | **1.8x slower** |
| ruff | 0.11s | 0.36s | **3.3x slower** |
| ruff-format | 0.01s | 0.02s | 2x slower |

## Key Findings

**prek is significantly slower on hooks that process multiple files concurrently:**
- `debug-statements`: 5.2x slower
- `name-tests-test`: 4x slower  
- `ruff check`: 3.3x slower

The pattern suggests that despite `prek` showing `concurrency=4` in the logs, it's not
batching/parallelizing files as efficiently as `pre-commit`.

Looking at the prek logs more carefully:
```
TRACE Executing `cd ... && python3 .../debug-statement-hook tests/basic_permutations_test.py [...]`
TRACE Executing `cd ... && python3 .../debug-statement-hook tests/expressions_test.py [...]`
```

It appears to be spawning **separate processes for small batches** of files, while `pre-commit`
likely passes all 11 files to a **single invocation** of each hook, letting the hook itself handle
the files efficiently.

The overhead of spawning multiple Python processes (each with startup cost) is killing performance.
That's your bottleneck!

---


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Slower to run some hooks (debug-statements, ruff) than pre-commit #872

Summary

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.pre-commit-config.yaml

Log file

Time Distribution Analysis

Why It's Slower

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Hook	pre-commit	prek	Difference
check-toml	0.19s	~instant	-
check-yaml	0.38s	~instant	-
debug-statements	0.10s	0.52s	5.2x slower
end-of-file-fixer	0.24s	~instant	-
name-tests-test	0.11s	0.44s	4x slower
trailing-whitespace	0.11s	~instant	-
toml-sort-fix	0.25s	0.25s	same
add-trailing-comma	0.42s	0.60s	1.4x slower
pyupgrade	0.49s	0.88s	1.8x slower
ruff	0.11s	0.36s	3.3x slower
ruff-format	0.01s	0.02s	2x slower

Slower to run some hooks (debug-statements, ruff) than pre-commit #872

Description

Summary

Platform

Version

.pre-commit-config.yaml

Log file

Time Distribution Analysis

Why It's Slower

Quick Wins

Comparison

Key Findings

Metadata

Metadata

Assignees

Labels

Projects

Milestone

Relationships

Development

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