288 lines
11 KiB
Python
288 lines
11 KiB
Python
# Copyright (c) Microsoft Corporation.
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# SPDX-License-Identifier: Apache-2.0
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# DeepSpeed Team
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import torch
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from deepspeed import comm as dist
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def print_rank_0(message):
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if dist.get_rank() == 0:
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print(message)
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class ContiguousMemoryAllocator(object):
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def __init__(self, size, dtype, device):
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self.buffer = torch.zeros(size, dtype=dtype, device=device)
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#address to contiguous size available
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self.contiguous_sizes = {}
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self.contiguous_sizes[0] = size
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#tensor id to its address
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self.tensor_addresses = {}
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#tensor address to its size
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self.tensor_sizes = {}
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#tensor address to ids
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self.tensor_ids = {}
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#id to tensors
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self.tensor_map = {}
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#id to params. Maps each tensor buffer to list of parameters that uses it
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self.id_to_params = {}
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self.total_size = size
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self.total_free = size
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self.largest_contiguous = size
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self.max_allocated = 0
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self.count = 0
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#create a tensor of size from the pre-allocated buffer
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#if not enough free space will fail
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#if not enough contiguous space, will defragment and allocate
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def allocate_tensor(self, size):
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free_before = self.total_free
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assert size <= self.total_free, "Not enough memory in buffer. Allocation failed"
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if self.largest_contiguous < size:
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print_rank_0("Needs defragmentation to allocate. Before Defragmentation:")
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self.print_allocation(resolution=100)
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self._defragment_memory()
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#set the param data to the new tensor buffer locations
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self._reset_param_data()
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print_rank_0("After defragmentation:")
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self.print_allocation(resolution=100)
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self.total_free = self.total_free - size
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allocated = self.total_size - self.total_free
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if allocated > self.max_allocated:
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self.max_allocated = allocated
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tensor_address = self._get_new_tensor_address(size)
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ret_tensor = self._get_new_tensor(tensor_address, size)
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print_rank_0(
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f"Free before allocation {free_before}. Allocating {size}. Free after allocation {self.total_free}. Max allocated {self.max_allocated}"
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)
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assert self.total_free + size == free_before, "Allocation bookkeeping error"
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return ret_tensor
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#assigns the tensor data to the param data and keeps track of the assignment
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#any change the underlying buffer from defragmentation will cause a
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#reassignment of the param data
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def assign_to_param(self, tensor, param, numel, shape):
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tensor_id = id(tensor)
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assert tensor_id in self.tensor_map.keys(), "No such tensor allocated by the allocator."
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assert tensor.numel() >= numel, "Assert tensor buffer does is not large enough"
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assert tensor_id not in self.id_to_params.keys(), "This tensor has already been assigned to a param"
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self.id_to_params[tensor_id] = [param]
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replicated_tensor = tensor.narrow(0, 0, numel).view(shape)
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param.data = replicated_tensor.data
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param.contiguous_tensor_id = tensor_id
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#deletes the tensor and frees up the underlying buffer
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def release_tensor(self, tensor):
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free_before = self.total_free
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tensor_id = id(tensor)
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tensor_size = tensor.numel()
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self._release_tensor(tensor_id)
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self._unassign_params(tensor_id)
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self.total_free += tensor_size
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print_rank_0(
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f"Free before release {free_before}. Released {tensor.numel()}. Total free after {self.total_free}.")
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assert self.total_free - tensor_size == free_before, "Release bookkeeping error"
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def release_tensor_with_id(self, tensor_id):
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free_before = self.total_free
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assert tensor_id in self.tensor_map.keys(), "Invalid tensor id"
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tensor = self.tensor_map[tensor_id]
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tensor_size = tensor.numel()
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self._release_tensor(tensor_id)
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self._unassign_params(tensor_id)
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self.total_free += tensor_size
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print_rank_0(
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f"Free before release {free_before}. Released {tensor.numel()}. Total free after {self.total_free}.")
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assert self.total_free - tensor_size == free_before, "Release bookkeeping error"
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#shows the current memory allocation at specified resolution
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def print_allocation(self, resolution=200):
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total_size = self.buffer.numel() * 1.0
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empty = []
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for addr, size in self.contiguous_sizes.items():
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start = int(addr * resolution / total_size)
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end = int((addr + size) * resolution / total_size)
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empty.extend(range(start, end))
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s = ''
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for i in range(resolution):
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s += '.' if i in empty else '|'
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print_rank_0(s)
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def max_allocated(self):
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return self.max_allocated
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#to be called after defragmentation that moves the tensor buffers
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#this call reassigns the data of all the parameters using the tensor buffers
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def _reset_param_data(self):
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for id, tensor in self.tensor_map.items():
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for param in self.id_to_params[id]:
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param.data = tensor.narrow(0, 0, param.numel()).view(param.data.shape).data
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def _unassign_params(self, tensor_id):
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if tensor_id in self.id_to_params.keys():
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del self.id_to_params[tensor_id]
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def _release_tensor(self, tensor_id):
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assert tensor_id in self.tensor_addresses, f"Tensor id {tensor_id} not found"
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address = self.tensor_addresses[tensor_id]
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contiguous_size = self.tensor_map[tensor_id].numel()
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del self.tensor_addresses[tensor_id]
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del self.tensor_ids[address]
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del self.tensor_map[tensor_id]
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del self.tensor_sizes[address]
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self._consolidate_address(address, contiguous_size)
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self.largest_contiguous = self._largest_contiguous()
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def _consolidate_address(self, address, contiguous_size):
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#consolidate next buffer
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end_address = address + contiguous_size
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if end_address in self.contiguous_sizes:
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contiguous_size += self.contiguous_sizes[end_address]
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del self.contiguous_sizes[end_address]
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#consolidate previous buffer
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for addr, size in self.contiguous_sizes.items():
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if addr + size == address:
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del self.contiguous_sizes[addr]
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contiguous_size += size
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address = addr
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break
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self.contiguous_sizes[address] = contiguous_size
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def _defragment_memory(self):
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empty_addresses = sorted(self.contiguous_sizes.keys())
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tensor_addresses = sorted(self.tensor_addresses.values())
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tensor_index = 0
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while tensor_index < len(tensor_addresses):
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empty_addr = empty_addresses[0]
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empty_size = self.contiguous_sizes[empty_addr]
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tensor_addr = tensor_addresses[tensor_index]
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tensor_size = self.tensor_sizes[tensor_addr]
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tensor_id = self.tensor_ids[tensor_addr]
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tensor = self.tensor_map[self.tensor_ids[tensor_addr]]
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assert tensor_size == tensor.numel(), \
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f"Size mismatch. {tensor_size} is allocated at addr {tensor_addr} but tensor size is {tensor.numel()} "
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assert empty_addr != tensor_addr, \
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f"Cannot have same empty address {empty_addr} and tensor address {tensor_addr}"
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if empty_addr < tensor_addr:
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if empty_size >= tensor_size:
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dest_buffer = self.buffer.narrow(0, empty_addr, tensor_size)
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src_buffer = self.buffer.narrow(0, tensor_addr, tensor_size)
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dest_buffer.data.copy_(src_buffer.data)
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else:
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#print_rank_0(f'empty addr : {empty_addr}, empty size {empty_size} tensor addr {tensor_addr} tensor size {tensor_size}')
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src_addr = tensor_addr
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dest_addr = empty_addr
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while src_addr < (tensor_addr + tensor_size):
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copy_size = min(empty_size, tensor_addr + tensor_size - src_addr)
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dest_buffer = self.buffer.narrow(0, dest_addr, copy_size)
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src_buffer = self.buffer.narrow(0, src_addr, copy_size)
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dest_buffer.data.copy_(src_buffer.data)
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src_addr += copy_size
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dest_addr += copy_size
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self._replace_old_address_with_new(tensor_id, empty_addr)
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tensor_index += 1
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else:
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tensor_index += 1
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empty_addresses = sorted(self.contiguous_sizes.keys())
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def _replace_old_address_with_new(self, tensor_id, new_address):
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tensor = self.tensor_map[tensor_id]
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tensor_size = tensor.numel()
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tensor.data = self.buffer.narrow(0, new_address, tensor_size).data
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self._release_tensor(tensor_id)
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self._mark_as_occupied(new_address, tensor_size)
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self.tensor_ids[new_address] = tensor_id
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self.tensor_map[tensor_id] = tensor
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self.tensor_addresses[tensor_id] = new_address
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self.tensor_sizes[new_address] = tensor_size
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def _get_new_tensor_address(self, size):
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tensor_address = None
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for address, contiguous_size in self.contiguous_sizes.items():
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if contiguous_size >= size and \
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(tensor_address is None or \
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contiguous_size < self.contiguous_sizes[tensor_address]):
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tensor_address = address
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assert tensor_address is not None, "address cannot be None"
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return tensor_address
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def _get_new_tensor(self, address, size):
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available_contiguous_size = self.contiguous_sizes[address]
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assert size <= available_contiguous_size, \
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f"Tensor numel {size} is large than available contiguous size {available_contiguous_size}"
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self.count += 1
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new_tensor = self.buffer.narrow(0, address, size)
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tensor_id = id(new_tensor)
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self.tensor_addresses[tensor_id] = address
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self.tensor_sizes[address] = size
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self.tensor_ids[address] = tensor_id
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self.tensor_map[tensor_id] = new_tensor
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self._mark_as_occupied(address, size)
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return new_tensor
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def _largest_contiguous(self):
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if len(self.contiguous_sizes) > 0:
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return max([size for _, size in self.contiguous_sizes.items()])
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else:
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return 0
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def _mark_as_occupied(self, address, size):
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available_contiguous_size = self.contiguous_sizes[address]
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del self.contiguous_sizes[address]
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if available_contiguous_size != size:
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self.contiguous_sizes[address + size] = available_contiguous_size - size
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self.largest_contiguous = self._largest_contiguous()
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