all inference code

music_dcae/distrib.py

@@ -0,0 +1,124 @@
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+# All rights reserved.
+#
+# This source code is licensed under the license found in the
+# LICENSE file in the root directory of this source tree.
+
+"""Torch distributed utilities."""
+
+import typing as tp
+
+import torch
+
+
+def rank():
+    if torch.distributed.is_initialized():
+        return torch.distributed.get_rank()
+    else:
+        return 0
+
+
+def world_size():
+    if torch.distributed.is_initialized():
+        return torch.distributed.get_world_size()
+    else:
+        return 1
+
+
+def is_distributed():
+    return world_size() > 1
+
+
+def all_reduce(tensor: torch.Tensor, op=torch.distributed.ReduceOp.SUM):
+    if is_distributed():
+        return torch.distributed.all_reduce(tensor, op)
+
+
+def _is_complex_or_float(tensor):
+    return torch.is_floating_point(tensor) or torch.is_complex(tensor)
+
+
+def _check_number_of_params(params: tp.List[torch.Tensor]):
+    # utility function to check that the number of params in all workers is the same,
+    # and thus avoid a deadlock with distributed all reduce.
+    if not is_distributed() or not params:
+        return
+    tensor = torch.tensor([len(params)], device=params[0].device, dtype=torch.long)
+    all_reduce(tensor)
+    if tensor.item() != len(params) * world_size():
+        # If not all the workers have the same number, for at least one of them,
+        # this inequality will be verified.
+        raise RuntimeError(f"Mismatch in number of params: ours is {len(params)}, "
+                           "at least one worker has a different one.")
+
+
+def broadcast_tensors(tensors: tp.Iterable[torch.Tensor], src: int = 0):
+    """Broadcast the tensors from the given parameters to all workers.
+    This can be used to ensure that all workers have the same model to start with.
+    """
+    if not is_distributed():
+        return
+    tensors = [tensor for tensor in tensors if _is_complex_or_float(tensor)]
+    _check_number_of_params(tensors)
+    handles = []
+    for tensor in tensors:
+        handle = torch.distributed.broadcast(tensor.data, src=src, async_op=True)
+        handles.append(handle)
+    for handle in handles:
+        handle.wait()
+
+
+def sync_buffer(buffers, average=True):
+    """
+    Sync grad for buffers. If average is False, broadcast instead of averaging.
+    """
+    if not is_distributed():
+        return
+    handles = []
+    for buffer in buffers:
+        if torch.is_floating_point(buffer.data):
+            if average:
+                handle = torch.distributed.all_reduce(
+                    buffer.data, op=torch.distributed.ReduceOp.SUM, async_op=True)
+            else:
+                handle = torch.distributed.broadcast(
+                    buffer.data, src=0, async_op=True)
+            handles.append((buffer, handle))
+    for buffer, handle in handles:
+        handle.wait()
+        if average:
+            buffer.data /= world_size
+
+
+def sync_grad(params):
+    """
+    Simpler alternative to DistributedDataParallel, that doesn't rely
+    on any black magic. For simple models it can also be as fast.
+    Just call this on your model parameters after the call to backward!
+    """
+    if not is_distributed():
+        return
+    handles = []
+    for p in params:
+        if p.grad is not None:
+            handle = torch.distributed.all_reduce(
+                p.grad.data, op=torch.distributed.ReduceOp.SUM, async_op=True)
+            handles.append((p, handle))
+    for p, handle in handles:
+        handle.wait()
+        p.grad.data /= world_size()
+
+
+def average_metrics(metrics: tp.Dict[str, float], count=1.):
+    """Average a dictionary of metrics across all workers, using the optional
+    `count` as unnormalized weight.
+    """
+    if not is_distributed():
+        return metrics
+    keys, values = zip(*metrics.items())
+    device = 'cuda' if torch.cuda.is_available() else 'cpu'
+    tensor = torch.tensor(list(values) + [1], device=device, dtype=torch.float32)
+    tensor *= count
+    all_reduce(tensor)
+    averaged = (tensor[:-1] / tensor[-1]).cpu().tolist()
+    return dict(zip(keys, averaged))