Add benchmarking utility

This will be useful for when wanting to run small benchmarks. It will
also allow us to remove a small snippet of code we previously had in the
tests.

Signed-off-by: Rodrigo Tobar <rtobar@icrar.org>

CHANGELOG.md

@@ -8,6 +8,7 @@
   declaring that our C extension doesn't need the GIL.
   In free-threaded builds the `gil_release_mode` parameter doesn't have any effect.
 * Added `CRC32CHash.checksum` auxiliary property.
+* Added new ``crc32c.benchmark`` utility for simple benchmarking.
 * The ``crc32c`` module doesn't fail to import when ``CRC32C_SW_MODE`` is ``none``
   and no hardware acceleration is found,
   making the act of importing the module less ackward.

README.rst

@@ -87,6 +87,10 @@ the following module-level values:
    is software- or hardware-based.
  * ``big_endian`` indicates whether the platform is big endian or not.
 
+A benchmarking utility can be found
+when executing the ``crc32c.benchmark`` module.
+Consult its help with the ``-h`` flag for options.
+
 Implementation details
 ----------------------
 

src/crc32c/benchmark.py

@@ -0,0 +1,44 @@
+import argparse
+import time
+
+from ._crc32c import crc32c
+
+DEFAULT_SIZE = 100 * 1024 * 1024
+DEFAULT_ITERATIONS = 10
+
+
+def run(size: int, iterations: int) -> float:
+    data = b" " * size
+    start = time.monotonic()
+    [crc32c(data) for _ in range(iterations)]
+    end = time.monotonic()
+    return end - start
+
+
+def main() -> None:
+
+    parser = argparse.ArgumentParser()
+    parser.add_argument(
+        "-s",
+        "--size",
+        type=int,
+        help=f"Amount of bytes to checksum, defaults to {DEFAULT_SIZE}",
+        default=DEFAULT_SIZE,
+    )
+    parser.add_argument(
+        "-i",
+        "--iterations",
+        type=int,
+        help=f"Number of times the checksum should we run over the data, defaults to {DEFAULT_ITERATIONS}",
+        default=DEFAULT_ITERATIONS,
+    )
+
+    options = parser.parse_args()
+    duration = run(options.size, options.iterations)
+    print(
+        f"crc32c ran at {options.size * options.iterations / duration / 1024 / 1024 / 1024:.3f} [GB/s]"
+    )
+
+
+if __name__ == "__main__":
+    main()

test/test_benchmark.py

@@ -0,0 +1,10 @@
+import subprocess
+import sys
+
+import pytest
+
+
+@pytest.mark.calculates_crc32c
+def test_benchmark() -> None:
+    out = subprocess.check_output([sys.executable, "-m", "crc32c.benchmark"])
+    assert b"crc32c ran at" in out