[PJRT C API] Add a helper method to check whether the backend is cloud TPU built after certain date.

Skip tests that are not intended to work with older version libtpu.

PiperOrigin-RevId: 610892754

Author: Jieying Luo

jax/_src/test_util.py

@@ -15,6 +15,7 @@
 
 from collections.abc import Generator, Iterable, Sequence
 from contextlib import contextmanager, ExitStack
+import datetime
 import inspect
 import io
 import functools
@@ -366,6 +367,24 @@ def is_device_cuda():
 def is_cloud_tpu():
   return running_in_cloud_tpu_vm
 
+# Returns True if it is not cloud TPU. If it is cloud TPU, returns True if it is
+# built at least `date``.
+# TODO(b/327203806): after libtpu adds a XLA version and the oldest support
+# libtpu contains the XLA version, remove using built time to skip tests.
+def if_cloud_tpu_at_least(date: datetime.date):
+  if not is_cloud_tpu():
+    return True
+  # The format of Cloud TPU platform_version is like:
+  # PJRT C API
+  # TFRT TPU v2
+  # Built on Oct 30 2023 03:04:42 (1698660263) cl/577737722
+  platform_version = xla_bridge.get_backend().platform_version.split('\n')[-1]
+  results = re.findall(r'\(.*?\)', platform_version)
+  if len(results) != 1:
+    return True
+  build_date = date.fromtimestamp(int(results[0][1:-1]))
+  return build_date >= date
+
 def pjrt_c_api_version_at_least(major_version: int, minor_version: int):
   pjrt_c_api_versions = xla_bridge.backend_pjrt_c_api_version()
   if pjrt_c_api_versions is None:

tests/memories_test.py

@@ -12,6 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import datetime
 import functools
 import math
 from absl.testing import absltest
@@ -1079,6 +1080,8 @@ class ActivationOffloadingTest(jtu.JaxTestCase):
   def setUp(self):
     if not jtu.test_device_matches(["tpu"]):
       self.skipTest("Memories do not work on CPU and GPU backends yet.")
+    if not jtu.if_cloud_tpu_at_least(datetime.date(2024, 2, 23)):
+      self.skipTest("Memories do not work on Cloud TPU older than 2024/02/23.")
     super().setUp()
 
   def test_remat_jaxpr_offloadable(self):

tests/pallas/pallas_call_tpu_test.py

@@ -14,6 +14,7 @@
 
 """Test TPU-specific extensions to pallas_call."""
 
+import datetime
 import functools
 from absl.testing import absltest
 from absl.testing import parameterized
@@ -48,6 +49,8 @@ def setUp(self):
     super().setUp()
     if not self.interpret and jtu.device_under_test() != 'tpu':
       self.skipTest('Only interpret mode supported on non-TPU')
+    if not jtu.if_cloud_tpu_at_least(datetime.date(2024, 2, 10)):
+      self.skipTest('Does not work on Cloud TPU older than 2024/02/10.')
 
   def pallas_call(self, *args, **kwargs):
     return pl.pallas_call(*args, **kwargs, interpret=self.interpret)
@@ -343,6 +346,8 @@ def dynamic_kernel(steps):
 
   # TODO(apaszke): Add tests for scalar_prefetch too
   def test_dynamic_grid_scalar_input(self):
+    if not jtu.if_cloud_tpu_at_least(datetime.date(2024, 2, 14)):
+      self.skipTest('Does not work on Cloud TPU older than 2024/02/14.')
     shape = (8, 128)
     result_ty = jax.ShapeDtypeStruct(shape, jnp.float32)
 
@@ -436,6 +441,9 @@ def dynamic_kernel(x, steps):
     )
 
   def test_num_programs(self):
+    if not jtu.if_cloud_tpu_at_least(datetime.date(2024, 2, 27)):
+      self.skipTest('Does not work on Cloud TPU older than 2024/02/27.')
+
     def kernel(y_ref):
       y_ref[0, 0] = pl.num_programs(0)
 
@@ -451,6 +459,9 @@ def dynamic_kernel(steps):
     self.assertEqual(dynamic_kernel(4), 8)
 
   def test_num_programs_block_spec(self):
+    if not jtu.if_cloud_tpu_at_least(datetime.date(2024, 2, 27)):
+      self.skipTest('Does not work on Cloud TPU older than 2024/02/27.')
+
     def kernel(x_ref, y_ref):
       y_ref[...] = x_ref[...]
 

tests/shard_alike_test.py

@@ -12,6 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import datetime
 import os
 
 import jax
@@ -66,6 +67,8 @@ def setUp(self):
     super().setUp()
     if xla_extension_version < 227:
       self.skipTest('Requires xla_extension_version >= 227')
+    if not jtu.if_cloud_tpu_at_least(datetime.date(2024, 2, 23)):
+      self.skipTest("Requires Cloud TPU older than 2024/02/23.")
 
   def test_basic(self):
     mesh = jtu.create_global_mesh((2, 2), ('x', 'y'))