diff --git a/swh/loader/mercurial/hgutil.py b/swh/loader/mercurial/hgutil.py
--- a/swh/loader/mercurial/hgutil.py
+++ b/swh/loader/mercurial/hgutil.py
@@ -2,6 +2,7 @@
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
+
 from collections import defaultdict
 from dataclasses import dataclass
 import io
@@ -154,12 +155,13 @@
 
     if process.is_alive():
         process.terminate()
-        # Give it a second (literally), then kill it
+        # Give it literally a second (in successive steps of 0.1 second), then kill it.
         # Can't use `process.join(1)` here, billiard appears to be bugged
         # https://github.com/celery/billiard/issues/270
         killed = False
+        step = 0.1
         for _ in range(10):
-            time.sleep(0.1)
+            time.sleep(step)
             if not process.is_alive():
                 break
         else:
diff --git a/swh/loader/mercurial/tests/test_hgutil.py b/swh/loader/mercurial/tests/test_hgutil.py
--- a/swh/loader/mercurial/tests/test_hgutil.py
+++ b/swh/loader/mercurial/tests/test_hgutil.py
@@ -16,11 +16,13 @@
     src = "https://www.mercurial-scm.org/repo/hello"
     dest = "/dev/null"
     timeout = 0.1
+    sleepy_time = 100 * timeout
+    assert sleepy_time > timeout
 
-    def clone(*args, **kwargs):
+    def clone(*args, sleepy_time=sleepy_time, **kwargs):
         # ignore SIGTERM to force sigkill
         signal.signal(signal.SIGTERM, lambda signum, frame: None)
-        time.sleep(2)
+        time.sleep(sleepy_time)  # we make sure we exceed the timeout
 
     monkeypatch.setattr(hg, "clone", clone)