Fix fp8-all-gather buck errors (#912)

Summary: Pull Request resolved: #912

Differential Revision: D63048850

Author: y-sq

test/float8/test_fsdp2/test_fsdp2.py

@@ -18,7 +18,7 @@
 from torchao.float8.config import CastConfig, Float8LinearConfig, ScalingType
 from torchao.float8.float8_linear_utils import convert_to_float8_training
 from torchao.float8.fsdp_utils import WeightWithDynamicFloat8CastTensor
-from fsdp2_common import check_parity_bf16_mp, check_parity_no_mp
+from torchao.testing.float8_fsdp2_utils import check_parity_bf16_mp, check_parity_no_mp
 from torch.distributed._composable.fsdp import fully_shard, MixedPrecisionPolicy
 from torch.distributed._tensor import DTensor
 from torch.testing._internal.common_cuda import TEST_CUDA

test/float8/test_fsdp2/fsdp2_common.py renamed to torchao/testing/float8_fsdp2_utils.py

@@ -49,9 +49,9 @@ def check_parity_no_mp(
                 precompute_float8_dynamic_scale_for_fsdp(model)
 
         if compile_transformer_block:
-            test_cls.assertEqual(losses[0], losses[1], atol=1e-4, rtol=1e-4)
+            test_cls.assertEqual(losses[0], losses[1], atol=1e-4, rtol=1e-4, msg = f"iter: {iter_idx}, loss-ref: {losses[0]}, loss-fp8: {losses[1]}")
         else:
-            test_cls.assertEqual(losses[0], losses[1])
+            test_cls.assertEqual(losses[0], losses[1], msg = f"iter: {iter_idx}, loss-ref: {losses[0]}, loss-fp8: {losses[1]}")
 
 
 def check_parity_bf16_mp(
@@ -86,4 +86,4 @@ def check_parity_bf16_mp(
                 ref_model.parameters(), ref_model_bf16.parameters()
             ):
                 param_bf16.detach().copy_(param_fp32)
-        test_cls.assertEqual(losses[0], losses[1])
+        test_cls.assertEqual(losses[0], losses[1], msg = f"iter: {iter_idx}, loss-ref: {losses[0]}, loss-fp8: {losses[1]}")