[mypyc] Add script to compile mypy with trace logging and run mypy (#19475)

Trace logging helps when analyzing low-level performance issues in mypy.

Author: JukkaL

misc/log_trace_check.py

@@ -0,0 +1,85 @@
+"""Compile mypy using mypyc with trace logging enabled, and collect a trace.
+
+The trace log can be used to analyze low-level performance bottlenecks.
+
+By default does a self check as the workload.
+
+This works on all supported platforms, unlike some of our other performance tools.
+"""
+
+from __future__ import annotations
+
+import argparse
+import glob
+import os
+import shutil
+import subprocess
+import sys
+import time
+
+from perf_compare import build_mypy, clone
+
+# Generated files, including binaries, go under this directory to avoid overwriting user state.
+TARGET_DIR = "mypy.log_trace.tmpdir"
+
+
+def perform_type_check(target_dir: str, code: str | None) -> None:
+    cache_dir = os.path.join(target_dir, ".mypy_cache")
+    if os.path.exists(cache_dir):
+        shutil.rmtree(cache_dir)
+    args = []
+    if code is None:
+        args.extend(["--config-file", "mypy_self_check.ini"])
+        for pat in "mypy/*.py", "mypy/*/*.py", "mypyc/*.py", "mypyc/test/*.py":
+            args.extend(glob.glob(pat))
+    else:
+        args.extend(["-c", code])
+    check_cmd = ["python", "-m", "mypy"] + args
+    t0 = time.time()
+    subprocess.run(check_cmd, cwd=target_dir, check=True)
+    elapsed = time.time() - t0
+    print(f"{elapsed:.2f}s elapsed")
+
+
+def main() -> None:
+    parser = argparse.ArgumentParser(
+        description="Compile mypy and collect a trace log while type checking (by default, self check)."
+    )
+    parser.add_argument(
+        "--multi-file",
+        action="store_true",
+        help="compile mypy into one C file per module (to reduce RAM use during compilation)",
+    )
+    parser.add_argument(
+        "--skip-compile", action="store_true", help="use compiled mypy from previous run"
+    )
+    parser.add_argument(
+        "-c",
+        metavar="CODE",
+        default=None,
+        type=str,
+        help="type check Python code fragment instead of mypy self-check",
+    )
+    args = parser.parse_args()
+    multi_file: bool = args.multi_file
+    skip_compile: bool = args.skip_compile
+    code: str | None = args.c
+
+    target_dir = TARGET_DIR
+
+    if not skip_compile:
+        clone(target_dir, "HEAD")
+
+        print(f"Building mypy in {target_dir} with trace logging enabled...")
+        build_mypy(target_dir, multi_file, log_trace=True, opt_level="0")
+    elif not os.path.isdir(target_dir):
+        sys.exit("error: Can't find compile mypy from previous run -- can't use --skip-compile")
+
+    perform_type_check(target_dir, code)
+
+    trace_fnam = os.path.join(target_dir, "mypyc_trace.txt")
+    print(f"Generated event trace log in {trace_fnam}")
+
+
+if __name__ == "__main__":
+    main()

misc/perf_compare.py

@@ -37,13 +37,22 @@ def heading(s: str) -> None:
     print()
 
 
-def build_mypy(target_dir: str, multi_file: bool, *, cflags: str | None = None) -> None:
+def build_mypy(
+    target_dir: str,
+    multi_file: bool,
+    *,
+    cflags: str | None = None,
+    log_trace: bool = False,
+    opt_level: str = "2",
+) -> None:
     env = os.environ.copy()
     env["CC"] = "clang"
-    env["MYPYC_OPT_LEVEL"] = "2"
+    env["MYPYC_OPT_LEVEL"] = opt_level
     env["PYTHONHASHSEED"] = "1"
     if multi_file:
         env["MYPYC_MULTI_FILE"] = "1"
+    if log_trace:
+        env["MYPYC_LOG_TRACE"] = "1"
     if cflags is not None:
         env["CFLAGS"] = cflags
     cmd = [sys.executable, "setup.py", "--use-mypyc", "build_ext", "--inplace"]

setup.py

@@ -145,13 +145,15 @@ def run(self) -> None:
     opt_level = os.getenv("MYPYC_OPT_LEVEL", "3")
     debug_level = os.getenv("MYPYC_DEBUG_LEVEL", "1")
     force_multifile = os.getenv("MYPYC_MULTI_FILE", "") == "1"
+    log_trace = bool(int(os.getenv("MYPYC_LOG_TRACE", "0")))
     ext_modules = mypycify(
         mypyc_targets + ["--config-file=mypy_bootstrap.ini"],
         opt_level=opt_level,
         debug_level=debug_level,
         # Use multi-file compilation mode on windows because without it
         # our Appveyor builds run out of memory sometimes.
         multi_file=sys.platform == "win32" or force_multifile,
+        log_trace=log_trace,
     )
 
 else: