diff --git a/google/api_core/retry.py b/google/api_core/retry.py
index ce496937b..961279a06 100644
--- a/google/api_core/retry.py
+++ b/google/api_core/retry.py
@@ -61,6 +61,7 @@ def check_if_exists():
 import logging
 import random
 import time
+import threading
 
 import requests.exceptions
 
@@ -69,9 +70,12 @@ def check_if_exists():
 from google.auth import exceptions as auth_exceptions
 
 _LOGGER = logging.getLogger(__name__)
-_DEFAULT_INITIAL_DELAY = 1.0  # seconds
-_DEFAULT_MAXIMUM_DELAY = 60.0  # seconds
-_DEFAULT_DELAY_MULTIPLIER = 2.0
+# _DEFAULT_INITIAL_DELAY = 1.0  # seconds
+# _DEFAULT_MAXIMUM_DELAY = 60.0  # seconds
+# _DEFAULT_DELAY_MULTIPLIER = 2.0
+_DEFAULT_INITIAL_DELAY = 2.0  # seconds
+_DEFAULT_MAXIMUM_DELAY = 2.0  # seconds
+_DEFAULT_DELAY_MULTIPLIER = 1.0
 _DEFAULT_DEADLINE = 60.0 * 2.0  # seconds
 
 
@@ -143,7 +147,11 @@ def exponential_sleep_generator(initial, maximum, multiplier=_DEFAULT_DELAY_MULT
     while True:
         # Introduce jitter by yielding a delay that is uniformly distributed
         # to average out to the delay time.
-        yield min(random.uniform(0.0, delay * 2.0), maximum)
+        res = min(random.uniform(0.0, delay * 2.0), maximum)
+        _LOGGER.debug(
+            f"xxxxx: {threading.current_thread().name} exponential_sleep_generator initial: {initial}s, maximum: {maximum}s, multipier: {multiplier}s, res:{res}s"
+        )
+        yield res
         delay = delay * multiplier
 
 
@@ -187,7 +195,10 @@ def retry_target(target, predicate, sleep_generator, deadline, on_error=None):
 
     for sleep in sleep_generator:
         try:
-            return target()
+            _LOGGER.debug(f"xxxxx: {threading.current_thread().name} before target sleep: {sleep}")
+            res = target()
+            _LOGGER.debug(f"xxxxx: {threading.current_thread().name} res: {res}")
+            return res
 
         # pylint: disable=broad-except
         # This function explicitly must deal with broad exceptions.
diff --git a/google/api_core/retry_async.py b/google/api_core/retry_async.py
index 68a255973..ac930f9bc 100644
--- a/google/api_core/retry_async.py
+++ b/google/api_core/retry_async.py
@@ -142,7 +142,7 @@ async def retry_target(target, predicate, sleep_generator, deadline, on_error=No
                 sleep = min(time_to_deadline, sleep)
 
         _LOGGER.debug(
-            "Retrying due to {}, sleeping {:.1f}s ...".format(last_exc, sleep)
+            "(Async) Retrying due to {}, sleeping {:.1f}s ...".format(last_exc, sleep)
         )
         await asyncio.sleep(sleep)