Improve hook duration timing

pre_commit/commands/run.py

@@ -187,7 +187,7 @@ def _run_single_hook(
 
         if not hook.pass_filenames:
             filenames = ()
-        time_before = time.time()
+        time_before = time.monotonic()
         language = languages[hook.language]
         with language.in_env(hook.prefix, hook.language_version):
             retcode, out = language.run_hook(
@@ -199,7 +199,7 @@ def _run_single_hook(
                 require_serial=hook.require_serial,
                 color=use_color,
             )
-        duration = round(time.time() - time_before, 2) or 0
+        duration = round(time.monotonic() - time_before, 2)
         diff_after = _get_diff()
 
         # if the hook makes changes, fail the commit
@@ -218,7 +218,7 @@ def _run_single_hook(
         _subtle_line(f'- hook id: {hook.id}', use_color)
 
         if (verbose or hook.verbose) and duration is not None:
-            _subtle_line(f'- duration: {duration}s', use_color)
+            _subtle_line(f'- duration: {duration:.2f}s', use_color)
 
         if retcode:
             _subtle_line(f'- exit code: {retcode}', use_color)

tests/commands/run_test.py

@@ -286,14 +286,14 @@ def test_global_files(cap_out, store, in_git_dir):
     ('t1', 't2', 'expected'),
     (
         (1.234, 2., b'\n- duration: 0.77s\n'),
-        (1., 1., b'\n- duration: 0s\n'),
+        (1., 1., b'\n- duration: 0.00s\n'),
     ),
 )
 def test_verbose_duration(cap_out, store, in_git_dir, t1, t2, expected):
     write_config('.', {'repo': 'meta', 'hooks': [{'id': 'identity'}]})
     cmd_output('git', 'add', '.')
     opts = run_opts(verbose=True)
-    with mock.patch.object(time, 'time', side_effect=(t1, t2)):
+    with mock.patch.object(time, 'monotonic', side_effect=(t1, t2)):
         ret, printed = _do_run(cap_out, store, str(in_git_dir), opts)
     assert ret == 0
     assert expected in printed

tests/commands/try_repo_test.py

@@ -43,7 +43,7 @@ def _run_try_repo(tempdir_factory, **kwargs):
 
 
 def test_try_repo_repo_only(cap_out, tempdir_factory):
-    with mock.patch.object(time, 'time', return_value=0.0):
+    with mock.patch.object(time, 'monotonic', return_value=0.0):
         _run_try_repo(tempdir_factory, verbose=True)
     start, config, rest = _get_out(cap_out)
     assert start == ''
@@ -62,7 +62,7 @@ def test_try_repo_repo_only(cap_out, tempdir_factory):
 - hook id: bash_hook
 Bash hook................................................................Passed
 - hook id: bash_hook2
-- duration: 0s
+- duration: 0.00s
 
 test-file