Add Ascend NPU accelerator support (#3595)

* add Ascend NPU accelerator support

* clean code

---------
Co-authored-by: Njializheng <jializheng@huawei.com>
Co-authored-by: NOlatunji Ruwase <olruwase@microsoft.com>

accelerator/npu_accelerator.py

+# Copyright (c) Microsoft Corporation.
+# SPDX-License-Identifier: Apache-2.0
+
+# DeepSpeed Team
+
+from .abstract_accelerator import DeepSpeedAccelerator
+# During setup stage torch may not be installed, pass on no torch will
+# allow op builder related API to be executed.
+try:
+    import torch.npu
+except ImportError:
+    pass
+
+
+class NPU_Accelerator(DeepSpeedAccelerator):
+
+    def __init__(self):
+        self._name = 'npu'
+        self._communication_backend_name = 'hccl'
+
+    def is_synchronized_device(self):
+        return False
+
+    # Device APIs
+    def device_name(self, device_index=None):
+        if device_index == None:
+            return 'npu'
+        return 'npu:{}'.format(device_index)
+
+    def device(self, device_index=None):
+        return torch.npu.device(device_index)
+
+    def set_device(self, device_index):
+        torch.npu.set_device(device_index)
+
+    def current_device(self):
+        return torch.npu.current_device()
+
+    def current_device_name(self):
+        return 'npu:{}'.format(torch.npu.current_device())
+
+    def device_count(self):
+        return torch.npu.device_count()
+
+    def synchronize(self, device_index=None):
+        return torch.npu.synchronize(device_index)
+
+    # RNG APIs
+    def random(self):
+        return torch.random
+
+    def set_rng_state(self, new_state, device_index=None):
+        if device_index is None:
+            return torch.npu.set_rng_state(new_state)
+
+        return torch.npu.set_rng_state(new_state, device_index)
+
+    def get_rng_state(self, device_index=None):
+        if device_index is None:
+            return torch.npu.get_rng_state()
+
+        return torch.npu.get_rng_state(device_index)
+
+    def manual_seed(self, seed):
+        return torch.npu.manual_seed(seed)
+
+    def manual_seed_all(self, seed):
+        return torch.npu.manual_seed_all(seed)
+
+    def initial_seed(self, seed):
+        return torch.npu.initial_seed(seed)
+
+    def default_generator(self, device_index):
+        return torch.npu.default_generators[device_index]
+
+    # Streams/Events
+    @property
+    def Stream(self):
+        return torch.npu.Stream
+
+    def stream(self, stream):
+        return torch.npu.stream(stream)
+
+    def current_stream(self, device_index=None):
+        return torch.npu.current_stream(device_index)
+
+    def default_stream(self, device_index=None):
+        return torch.npu.default_stream(device_index)
+
+    @property
+    def Event(self):
+        return torch.npu.Event
+
+    # Memory management
+    def empty_cache(self):
+        return torch.npu.empty_cache()
+
+    def memory_allocated(self, device_index=None):
+        return torch.npu.memory_allocated(device_index)
+
+    def max_memory_allocated(self, device_index=None):
+        return torch.npu.max_memory_allocated(device_index)
+
+    def reset_max_memory_allocated(self, device_index=None):
+        return torch.npu.reset_max_memory_allocated(device_index)
+
+    def memory_cached(self, device_index=None):
+        return torch.npu.memory_cached(device_index)
+
+    def max_memory_cached(self, device_index=None):
+        return torch.npu.max_memory_cached(device_index)
+
+    def reset_max_memory_cached(self, device_index=None):
+        return torch.npu.reset_max_memory_cached(device_index)
+
+    def memory_stats(self, device_index=None):
+        if hasattr(torch.npu, 'memory_stats'):
+            return torch.npu.memory_stats(device_index)
+
+    def reset_peak_memory_stats(self, device_index=None):
+        if hasattr(torch.npu, 'reset_peak_memory_stats'):
+            return torch.npu.reset_peak_memory_stats(device_index)
+
+    def memory_reserved(self, device_index=None):
+        if hasattr(torch.npu, 'memory_reserved'):
+            return torch.npu.memory_reserved(device_index)
+
+    def max_memory_reserved(self, device_index=None):
+        if hasattr(torch.npu, 'max_memory_reserved'):
+            return torch.npu.max_memory_reserved(device_index)
+
+    def total_memory(self, device_index=None):
+        return torch.npu.get_device_properties(device_index).total_memory
+
+    # Data types
+    def is_bf16_supported(self):
+        return torch.npu.is_bf16_supported()
+
+    def is_fp16_supported(self):
+        return True
+
+    # Misc
+    def amp(self):
+        if hasattr(torch.npu, 'amp'):
+            return torch.npu.amp
+        return None
+
+    def is_available(self):
+        return torch.npu.is_available()
+
+    def range_push(self, msg):
+        return
+
+    def range_pop(self):
+        return
+
+    def lazy_call(self, callback):
+        return torch.npu._lazy_call(callback)
+
+    def communication_backend_name(self):
+        return self._communication_backend_name
+
+    # Tensor operations
+
+    @property
+    def BFloat16Tensor(self):
+        return torch.npu.BFloat16Tensor
+
+    @property
+    def ByteTensor(self):
+        return torch.npu.ByteTensor
+
+    @property
+    def DoubleTensor(self):
+        return torch.npu.DoubleTensor
+
+    @property
+    def FloatTensor(self):
+        return torch.npu.FloatTensor
+
+    @property
+    def HalfTensor(self):
+        return torch.npu.HalfTensor
+
+    @property
+    def IntTensor(self):
+        return torch.npu.IntTensor
+
+    @property
+    def LongTensor(self):
+        return torch.npu.LongTensor
+
+    def pin_memory(self, tensor):
+        return tensor.pin_memory()
+
+    def on_accelerator(self, tensor):
+        device_str = str(tensor.device)
+        if device_str.startswith('npu:'):
+            return True
+        else:
+            return False
+
+    def op_builder_dir(self):
+        try:
+            # is op_builder from deepspeed or a 3p version? this should only succeed if it's deepspeed
+            # if successful this also means we're doing a local install and not JIT compile path
+            from op_builder import __deepspeed__  # noqa: F401
+            return "op_builder.npu"
+        except ImportError:
+            return "deepspeed.ops.op_builder.npu"
+
+    # dict that holds class name <--> class type mapping i.e.
+    # 'AsyncIOBuilder': <class 'op_builder.async_io.AsyncIOBuilder'>
+    # this dict will be filled at init stage
+    class_dict = None
+
+    def _lazy_init_class_dict(self):
+        if self.class_dict != None:
+            return
+        else:
+            self.class_dict = {}
+
+    # create an instance of op builder and return, name specified by class_name
+    def create_op_builder(self, class_name):
+        self._lazy_init_class_dict()
+        if class_name in self.class_dict:
+            return self.class_dict[class_name]()
+        else:
+            return None
+
+    # return an op builder class, name specified by class_name
+    def get_op_builder(self, class_name):
+        self._lazy_init_class_dict()
+        if class_name in self.class_dict:
+            return self.class_dict[class_name]
+        else:
+            return None
+
+    def build_extension(self):
+        from torch.utils.cpp_extension import BuildExtension
+        return BuildExtension