send weights to target device instead of CPU memory
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@ -155,10 +155,16 @@ class LoadStateDictOnMeta(ReplaceHelper):
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```
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"""
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def __init__(self, state_dict, device):
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def __init__(self, state_dict, device, weight_dtype_conversion=None):
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super().__init__()
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self.state_dict = state_dict
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self.device = device
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self.weight_dtype_conversion = weight_dtype_conversion or {}
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self.default_dtype = self.weight_dtype_conversion.get('')
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def get_weight_dtype(self, key):
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key_first_term, _ = key.split('.', 1)
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return self.weight_dtype_conversion.get(key_first_term, self.default_dtype)
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def __enter__(self):
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if shared.cmd_opts.disable_model_loading_ram_optimization:
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@ -167,24 +173,24 @@ class LoadStateDictOnMeta(ReplaceHelper):
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sd = self.state_dict
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device = self.device
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def load_from_state_dict(original, self, state_dict, prefix, *args, **kwargs):
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def load_from_state_dict(original, module, state_dict, prefix, *args, **kwargs):
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used_param_keys = []
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for name, param in self._parameters.items():
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for name, param in module._parameters.items():
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if param is None:
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continue
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key = prefix + name
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sd_param = sd.pop(key, None)
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if sd_param is not None:
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state_dict[key] = sd_param
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state_dict[key] = sd_param.to(dtype=self.get_weight_dtype(key))
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used_param_keys.append(key)
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if param.is_meta:
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dtype = sd_param.dtype if sd_param is not None else param.dtype
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self._parameters[name] = torch.nn.parameter.Parameter(torch.zeros_like(param, device=device, dtype=dtype), requires_grad=param.requires_grad)
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module._parameters[name] = torch.nn.parameter.Parameter(torch.zeros_like(param, device=device, dtype=dtype), requires_grad=param.requires_grad)
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for name in self._buffers:
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for name in module._buffers:
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key = prefix + name
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sd_param = sd.pop(key, None)
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@ -192,12 +198,12 @@ class LoadStateDictOnMeta(ReplaceHelper):
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state_dict[key] = sd_param
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used_param_keys.append(key)
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original(self, state_dict, prefix, *args, **kwargs)
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original(module, state_dict, prefix, *args, **kwargs)
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for key in used_param_keys:
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state_dict.pop(key, None)
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def load_state_dict(original, self, state_dict, strict=True):
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def load_state_dict(original, module, state_dict, strict=True):
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"""torch makes a lot of copies of the dictionary with weights, so just deleting entries from state_dict does not help
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because the same values are stored in multiple copies of the dict. The trick used here is to give torch a dict with
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all weights on meta device, i.e. deleted, and then it doesn't matter how many copies torch makes.
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@ -212,7 +218,7 @@ class LoadStateDictOnMeta(ReplaceHelper):
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if state_dict == sd:
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state_dict = {k: v.to(device="meta", dtype=v.dtype) for k, v in state_dict.items()}
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original(self, state_dict, strict=strict)
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original(module, state_dict, strict=strict)
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module_load_state_dict = self.replace(torch.nn.Module, 'load_state_dict', lambda *args, **kwargs: load_state_dict(module_load_state_dict, *args, **kwargs))
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module_load_from_state_dict = self.replace(torch.nn.Module, '_load_from_state_dict', lambda *args, **kwargs: load_from_state_dict(module_load_from_state_dict, *args, **kwargs))
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@ -518,6 +518,13 @@ def send_model_to_cpu(m):
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devices.torch_gc()
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def model_target_device():
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if shared.cmd_opts.lowvram or shared.cmd_opts.medvram:
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return devices.cpu
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else:
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return devices.device
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def send_model_to_device(m):
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if shared.cmd_opts.lowvram or shared.cmd_opts.medvram:
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lowvram.setup_for_low_vram(m, shared.cmd_opts.medvram)
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@ -579,7 +586,15 @@ def load_model(checkpoint_info=None, already_loaded_state_dict=None):
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timer.record("create model")
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with sd_disable_initialization.LoadStateDictOnMeta(state_dict, devices.cpu):
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if shared.cmd_opts.no_half:
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weight_dtype_conversion = None
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else:
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weight_dtype_conversion = {
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'first_stage_model': None,
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'': torch.float16,
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}
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with sd_disable_initialization.LoadStateDictOnMeta(state_dict, device=model_target_device(), weight_dtype_conversion=weight_dtype_conversion):
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load_model_weights(sd_model, checkpoint_info, state_dict, timer)
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timer.record("load weights from state dict")
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