RHOAIENG-3771 - Reduce execution time of E2E tests

Author: jiripetrlik

Diff for: tests/e2e/mnist.py

@@ -19,7 +19,7 @@
 from pytorch_lightning.callbacks.progress import TQDMProgressBar
 from torch import nn
 from torch.nn import functional as F
-from torch.utils.data import DataLoader, random_split
+from torch.utils.data import DataLoader, random_split, RandomSampler
 from torchmetrics import Accuracy
 from torchvision import transforms
 from torchvision.datasets import MNIST
@@ -127,7 +127,11 @@ def setup(self, stage=None):
             )
 
     def train_dataloader(self):
-        return DataLoader(self.mnist_train, batch_size=BATCH_SIZE)
+        return DataLoader(
+            self.mnist_train,
+            batch_size=BATCH_SIZE,
+            sampler=RandomSampler(self.mnist_train, num_samples=1000),
+        )
 
     def val_dataloader(self):
         return DataLoader(self.mnist_val, batch_size=BATCH_SIZE)
@@ -147,10 +151,11 @@ def test_dataloader(self):
 trainer = Trainer(
     accelerator="auto",
     # devices=1 if torch.cuda.is_available() else None,  # limiting got iPython runs
-    max_epochs=5,
+    max_epochs=3,
     callbacks=[TQDMProgressBar(refresh_rate=20)],
     num_nodes=int(os.environ.get("GROUP_WORLD_SIZE", 1)),
     devices=int(os.environ.get("LOCAL_WORLD_SIZE", 1)),
+    replace_sampler_ddp=False,
     strategy="ddp",
 )