[GitHub] szha closed pull request #11370: fix recordfile dataset with multi worker

[GitBox <gi...@apache.org>]

szha closed pull request #11370: fix recordfile dataset with multi worker
URL: https://github.com/apache/incubator-mxnet/pull/11370
 
 
   

This is a PR merged from a forked repository.
As GitHub hides the original diff on merge, it is displayed below for
the sake of provenance:

As this is a foreign pull request (from a fork), the diff is supplied
below (as it won't show otherwise due to GitHub magic):

diff --git a/python/mxnet/gluon/data/dataloader.py b/python/mxnet/gluon/data/dataloader.py
index 29b9b81aca0..eb1eb419cd0 100644
--- a/python/mxnet/gluon/data/dataloader.py
+++ b/python/mxnet/gluon/data/dataloader.py
@@ -151,6 +151,7 @@ def default_mp_batchify_fn(data):
 
 def worker_loop(dataset, key_queue, data_queue, batchify_fn):
     """Worker loop for multiprocessing DataLoader."""
+    dataset._fork()
     while True:
         idx, samples = key_queue.get()
         if idx is None:
diff --git a/python/mxnet/gluon/data/dataset.py b/python/mxnet/gluon/data/dataset.py
index bf5fa0a6d1e..13e2b57a8c5 100644
--- a/python/mxnet/gluon/data/dataset.py
+++ b/python/mxnet/gluon/data/dataset.py
@@ -94,6 +94,11 @@ def base_fn(x, *args):
             return fn(x)
         return self.transform(base_fn, lazy)
 
+    def _fork(self):
+        """Protective operations required when launching multiprocess workers."""
+        # for non file descriptor related datasets, just skip
+        pass
+
 
 class SimpleDataset(Dataset):
     """Simple Dataset wrapper for lists and arrays.
@@ -173,8 +178,12 @@ class RecordFileDataset(Dataset):
         Path to rec file.
     """
     def __init__(self, filename):
-        idx_file = os.path.splitext(filename)[0] + '.idx'
-        self._record = recordio.MXIndexedRecordIO(idx_file, filename, 'r')
+        self.idx_file = os.path.splitext(filename)[0] + '.idx'
+        self.filename = filename
+        self._fork()
+
+    def _fork(self):
+        self._record = recordio.MXIndexedRecordIO(self.idx_file, self.filename, 'r')
 
     def __getitem__(self, idx):
         return self._record.read_idx(self._record.keys[idx])
diff --git a/tests/python/unittest/test_gluon_data.py b/tests/python/unittest/test_gluon_data.py
index ef2ba2ab9b2..043804487b5 100644
--- a/tests/python/unittest/test_gluon_data.py
+++ b/tests/python/unittest/test_gluon_data.py
@@ -72,6 +72,18 @@ def test_recordimage_dataset():
         assert x.shape[0] == 1 and x.shape[3] == 3
         assert y.asscalar() == i
 
+@with_seed()
+def test_recordimage_dataset_with_data_loader_multiworker():
+    # This test is pointless on Windows because Windows doesn't fork
+    if platform.system() != 'Windows':
+        recfile = prepare_record()
+        dataset = gluon.data.vision.ImageRecordDataset(recfile)
+        loader = gluon.data.DataLoader(dataset, 1, num_workers=5)
+
+        for i, (x, y) in enumerate(loader):
+            assert x.shape[0] == 1 and x.shape[3] == 3
+            assert y.asscalar() == i
+
 @with_seed()
 def test_sampler():
     seq_sampler = gluon.data.SequentialSampler(10)
diff --git a/tests/python/unittest/test_io.py b/tests/python/unittest/test_io.py
index f0928a6b61a..dbd327d429f 100644
--- a/tests/python/unittest/test_io.py
+++ b/tests/python/unittest/test_io.py
@@ -407,7 +407,8 @@ def test_ImageRecordIter_seed_augmentation():
         mean_img="data/cifar/cifar10_mean.bin",
         shuffle=False,
         data_shape=(3, 28, 28),
-        batch_size=3)
+        batch_size=3,
+        seed_aug=seed_aug)
     batch = dataiter.next()
     data = batch.data[0].asnumpy().astype(np.uint8)
 


 

----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on GitHub and use the
URL above to go to the specific comment.
 
For queries about this service, please contact Infrastructure at:
users@infra.apache.org


With regards,
Apache Git Services