backend/memory_management.py

# Cherry-picked some good parts from ComfyUI with some bad parts fixed

import sys
import time
import psutil
import torch
import platform

from enum import Enum
from backend import stream
from backend.args import args


cpu = torch.device('cpu')


class VRAMState(Enum):
    DISABLED = 0  # No vram present: no need to move models to vram
    NO_VRAM = 1  # Very low vram: enable all the options to save vram
    LOW_VRAM = 2
    NORMAL_VRAM = 3
    HIGH_VRAM = 4
    SHARED = 5  # No dedicated vram: memory shared between CPU and GPU but models still need to be moved between both.


class CPUState(Enum):
    GPU = 0
    CPU = 1
    MPS = 2


# Determine VRAM State
vram_state = VRAMState.NORMAL_VRAM
set_vram_to = VRAMState.NORMAL_VRAM
cpu_state = CPUState.GPU

total_vram = 0

lowvram_available = True
xpu_available = False

if args.pytorch_deterministic:
    print("Using deterministic algorithms for pytorch")
    torch.use_deterministic_algorithms(True, warn_only=True)

directml_enabled = False
if args.directml is not None:
    import torch_directml

    directml_enabled = True
    device_index = args.directml
    if device_index < 0:
        directml_device = torch_directml.device()
    else:
        directml_device = torch_directml.device(device_index)
    print("Using directml with device: {}".format(torch_directml.device_name(device_index)))

try:
    import intel_extension_for_pytorch as ipex

    if torch.xpu.is_available():
        xpu_available = True
except:
    pass

try:
    if torch.backends.mps.is_available():
        cpu_state = CPUState.MPS
        import torch.mps
except:
    pass

if args.always_cpu:
    cpu_state = CPUState.CPU


def is_intel_xpu():
    global cpu_state
    global xpu_available
    if cpu_state == CPUState.GPU:
        if xpu_available:
            return True
    return False


def get_torch_device():
    global directml_enabled
    global cpu_state
    if directml_enabled:
        global directml_device
        return directml_device
    if cpu_state == CPUState.MPS:
        return torch.device("mps")
    if cpu_state == CPUState.CPU:
        return torch.device("cpu")
    else:
        if is_intel_xpu():
            return torch.device("xpu", torch.xpu.current_device())
        else:
            return torch.device(torch.cuda.current_device())


def get_total_memory(dev=None, torch_total_too=False):
    global directml_enabled
    if dev is None:
        dev = get_torch_device()

    if hasattr(dev, 'type') and (dev.type == 'cpu' or dev.type == 'mps'):
        mem_total = psutil.virtual_memory().total
        mem_total_torch = mem_total
    else:
        if directml_enabled:
            mem_total = 1024 * 1024 * 1024  # TODO
            mem_total_torch = mem_total
        elif is_intel_xpu():
            stats = torch.xpu.memory_stats(dev)
            mem_reserved = stats['reserved_bytes.all.current']
            mem_total_torch = mem_reserved
            mem_total = torch.xpu.get_device_properties(dev).total_memory
        else:
            stats = torch.cuda.memory_stats(dev)
            mem_reserved = stats['reserved_bytes.all.current']
            _, mem_total_cuda = torch.cuda.mem_get_info(dev)
            mem_total_torch = mem_reserved
            mem_total = mem_total_cuda

    if torch_total_too:
        return (mem_total, mem_total_torch)
    else:
        return mem_total


total_vram = get_total_memory(get_torch_device()) / (1024 * 1024)
total_ram = psutil.virtual_memory().total / (1024 * 1024)
print("Total VRAM {:0.0f} MB, total RAM {:0.0f} MB".format(total_vram, total_ram))

try:
    print("pytorch version: {}".format(torch.version.__version__))
except:
    pass

try:
    OOM_EXCEPTION = torch.cuda.OutOfMemoryError
except:
    OOM_EXCEPTION = Exception

if directml_enabled:
    OOM_EXCEPTION = Exception

XFORMERS_VERSION = ""
XFORMERS_ENABLED_VAE = True
if args.disable_xformers:
    XFORMERS_IS_AVAILABLE = False
else:
    try:
        import xformers
        import xformers.ops

        XFORMERS_IS_AVAILABLE = True
        try:
            XFORMERS_IS_AVAILABLE = xformers._has_cpp_library
        except:
            pass
        try:
            XFORMERS_VERSION = xformers.version.__version__
            print("xformers version: {}".format(XFORMERS_VERSION))
            if XFORMERS_VERSION.startswith("0.0.18"):
                print("\nWARNING: This version of xformers has a major bug where you will get black images when generating high resolution images.")
                print("Please downgrade or upgrade xformers to a different version.\n")
                XFORMERS_ENABLED_VAE = False
        except:
            pass
    except:
        XFORMERS_IS_AVAILABLE = False


def is_nvidia():
    global cpu_state
    if cpu_state == CPUState.GPU:
        if torch.version.cuda:
            return True
    return False


ENABLE_PYTORCH_ATTENTION = False
if args.attention_pytorch:
    ENABLE_PYTORCH_ATTENTION = True
    XFORMERS_IS_AVAILABLE = False

VAE_DTYPES = [torch.float32]

try:
    if is_nvidia():
        torch_version = torch.version.__version__
        if int(torch_version[0]) >= 2:
            if ENABLE_PYTORCH_ATTENTION == False and args.attention_split == False and args.attention_quad == False:
                ENABLE_PYTORCH_ATTENTION = True
            if torch.cuda.is_bf16_supported() and torch.cuda.get_device_properties(torch.cuda.current_device()).major >= 8:
                VAE_DTYPES = [torch.bfloat16] + VAE_DTYPES
    if is_intel_xpu():
        if args.attention_split == False and args.attention_quad == False:
            ENABLE_PYTORCH_ATTENTION = True
except:
    pass

if is_intel_xpu():
    VAE_DTYPES = [torch.bfloat16] + VAE_DTYPES

if args.vae_in_cpu:
    VAE_DTYPES = [torch.float32]

VAE_ALWAYS_TILED = False

if ENABLE_PYTORCH_ATTENTION:
    torch.backends.cuda.enable_math_sdp(True)
    torch.backends.cuda.enable_flash_sdp(True)
    torch.backends.cuda.enable_mem_efficient_sdp(True)

if args.always_low_vram:
    set_vram_to = VRAMState.LOW_VRAM
    lowvram_available = True
elif args.always_no_vram:
    set_vram_to = VRAMState.NO_VRAM
elif args.always_high_vram or args.always_gpu:
    vram_state = VRAMState.HIGH_VRAM

FORCE_FP32 = False
FORCE_FP16 = False
if args.all_in_fp32:
    print("Forcing FP32, if this improves things please report it.")
    FORCE_FP32 = True

if args.all_in_fp16:
    print("Forcing FP16.")
    FORCE_FP16 = True

if lowvram_available:
    if set_vram_to in (VRAMState.LOW_VRAM, VRAMState.NO_VRAM):
        vram_state = set_vram_to

if cpu_state != CPUState.GPU:
    vram_state = VRAMState.DISABLED

if cpu_state == CPUState.MPS:
    vram_state = VRAMState.SHARED

print(f"Set vram state to: {vram_state.name}")

ALWAYS_VRAM_OFFLOAD = args.always_offload_from_vram

if ALWAYS_VRAM_OFFLOAD:
    print("Always offload VRAM")

PIN_SHARED_MEMORY = args.pin_shared_memory

if PIN_SHARED_MEMORY:
    print("Always pin shared GPU memory")


def get_torch_device_name(device):
    if hasattr(device, 'type'):
        if device.type == "cuda":
            try:
                allocator_backend = torch.cuda.get_allocator_backend()
            except:
                allocator_backend = ""
            return "{} {} : {}".format(device, torch.cuda.get_device_name(device), allocator_backend)
        else:
            return "{}".format(device.type)
    elif is_intel_xpu():
        return "{} {}".format(device, torch.xpu.get_device_name(device))
    else:
        return "CUDA {}: {}".format(device, torch.cuda.get_device_name(device))


try:
    torch_device_name = get_torch_device_name(get_torch_device())
    print("Device: {}".format(torch_device_name))
except:
    torch_device_name = ''
    print("Could not pick default device.")

if 'rtx' in torch_device_name.lower():
    if not args.cuda_malloc:
        print('Hint: your device supports --cuda-malloc for potential speed improvements.')


current_loaded_models = []


def state_dict_size(sd, exclude_device=None):
    module_mem = 0
    for k in sd:
        t = sd[k]

        if exclude_device is not None:
            if t.device == exclude_device:
                continue

        module_mem += t.nelement() * t.element_size()
    return module_mem


def state_dict_dtype(state_dict):
    for k, v in state_dict.items():
        if hasattr(v, 'is_gguf'):
            return 'gguf'
        if 'bitsandbytes__nf4' in k:
            return 'nf4'
        if 'bitsandbytes__fp4' in k:
            return 'fp4'

    dtype_counts = {}

    for tensor in state_dict.values():
        dtype = tensor.dtype
        if dtype in dtype_counts:
            dtype_counts[dtype] += 1
        else:
            dtype_counts[dtype] = 1

    major_dtype = None
    max_count = 0

    for dtype, count in dtype_counts.items():
        if count > max_count:
            max_count = count
            major_dtype = dtype

    return major_dtype


def module_size(module, exclude_device=None):
    module_mem = 0
    for p in module.parameters():
        t = p.data

        if exclude_device is not None:
            if t.device == exclude_device:
                continue

        element_size = t.element_size()

        if getattr(p, 'quant_type', None) in ['fp4', 'nf4']:
            if element_size > 1:
                # not quanted yet
                element_size = 0.55  # a bit more than 0.5 because of quant state parameters
            else:
                # quanted
                element_size = 1.1  # a bit more than 0.5 because of quant state parameters

        module_mem += t.nelement() * element_size
    return module_mem


class LoadedModel:
    def __init__(self, model, memory_required):
        self.model = model
        self.memory_required = memory_required
        self.model_accelerated = False
        self.device = model.load_device

    def model_memory(self):
        return self.model.model_size()

    def model_memory_required(self, device=None):
        return module_size(self.model.model, exclude_device=device)

    def model_load(self, model_gpu_memory_when_using_cpu_swap=-1):
        patch_model_to = None
        do_not_need_cpu_swap = model_gpu_memory_when_using_cpu_swap < 0

        if do_not_need_cpu_swap:
            patch_model_to = self.device

        self.model.model_patches_to(self.device)
        self.model.model_patches_to(self.model.model_dtype())

        try:
            self.real_model = self.model.forge_patch_model(patch_model_to)
            self.model.current_device = self.model.load_device
        except Exception as e:
            self.model.forge_unpatch_model(self.model.offload_device)
            self.model_unload()
            raise e

        if not do_not_need_cpu_swap:
            memory_in_swap = 0
            mem_counter = 0
            mem_cannot_cast = 0
            for m in self.real_model.modules():
                if hasattr(m, "parameters_manual_cast"):
                    m.prev_parameters_manual_cast = m.parameters_manual_cast
                    m.parameters_manual_cast = True
                    module_mem = module_size(m)
                    if mem_counter + module_mem < model_gpu_memory_when_using_cpu_swap:
                        m.to(self.device)
                        mem_counter += module_mem
                    else:
                        memory_in_swap += module_mem
                        m.to(self.model.offload_device)
                        if PIN_SHARED_MEMORY and is_device_cpu(self.model.offload_device):
                            m._apply(lambda x: x.pin_memory())
                elif hasattr(m, "weight"):
                    m.to(self.device)
                    module_mem = module_size(m)
                    mem_counter += module_mem
                    mem_cannot_cast += module_mem

            if mem_cannot_cast > 0:
                print(f"[Memory Management] Loaded to GPU for backward capability: {mem_cannot_cast / (1024 * 1024):.2f} MB")

            swap_flag = 'Shared' if PIN_SHARED_MEMORY else 'CPU'
            method_flag = 'asynchronous' if stream.should_use_stream() else 'blocked'
            print(f"[Memory Management] Loaded to {swap_flag} Swap: {memory_in_swap / (1024 * 1024):.2f} MB ({method_flag} method)")
            print(f"[Memory Management] Loaded to GPU: {mem_counter / (1024 * 1024):.2f} MB")

            self.model_accelerated = True

        if is_intel_xpu() and not args.disable_ipex_hijack:
            self.real_model = torch.xpu.optimize(self.real_model.eval(), inplace=True, auto_kernel_selection=True, graph_mode=True)

        return self.real_model

    def model_unload(self, avoid_model_moving=False):
        if self.model_accelerated:
            for m in self.real_model.modules():
                if hasattr(m, "prev_parameters_manual_cast"):
                    m.parameters_manual_cast = m.prev_parameters_manual_cast
                    del m.prev_parameters_manual_cast

            self.model_accelerated = False

        if avoid_model_moving:
            self.model.forge_unpatch_model()
        else:
            self.model.forge_unpatch_model(self.model.offload_device)
            self.model.model_patches_to(self.model.offload_device)

    def __eq__(self, other):
        return self.model is other.model  # and self.memory_required == other.memory_required


current_inference_memory = 1024 * 1024 * 1024


def minimum_inference_memory():
    global current_inference_memory
    return current_inference_memory


def unload_model_clones(model):
    to_unload = []
    for i in range(len(current_loaded_models)):
        if model.is_clone(current_loaded_models[i].model):
            to_unload = [i] + to_unload

    if len(to_unload) > 0:
        print(f"Reuse {len(to_unload)} loaded models")

    for i in to_unload:
        current_loaded_models.pop(i).model_unload(avoid_model_moving=True)


def free_memory(memory_required, device, keep_loaded=[]):
    print(f"[Unload] Trying to free {memory_required / (1024 * 1024):.2f} MB for {device} with {len(keep_loaded)} models keep loaded ...")

    offload_everything = ALWAYS_VRAM_OFFLOAD or vram_state == VRAMState.NO_VRAM
    unloaded_model = False
    for i in range(len(current_loaded_models) - 1, -1, -1):
        if not offload_everything:
            free_memory = get_free_memory(device)
            print(f"[Unload] Current free memory is {free_memory / (1024 * 1024):.2f} MB ... ")
            if free_memory > memory_required:
                break
        shift_model = current_loaded_models[i]
        if shift_model.device == device:
            if shift_model not in keep_loaded:
                m = current_loaded_models.pop(i)
                print(f"[Unload] Unload model {m.model.model.__class__.__name__}")
                m.model_unload()
                del m
                unloaded_model = True

    if unloaded_model:
        soft_empty_cache()
    else:
        if vram_state != VRAMState.HIGH_VRAM:
            mem_free_total, mem_free_torch = get_free_memory(device, torch_free_too=True)
            if mem_free_torch > mem_free_total * 0.25:
                soft_empty_cache()


def compute_model_gpu_memory_when_using_cpu_swap(current_free_mem, inference_memory):
    maximum_memory_available = current_free_mem - inference_memory

    suggestion = max(
        maximum_memory_available / 1.3,
        maximum_memory_available - 1024 * 1024 * 1024 * 1.25
    )

    return int(max(0, suggestion))


def load_models_gpu(models, memory_required=0):
    global vram_state

    execution_start_time = time.perf_counter()
    extra_mem = max(minimum_inference_memory(), memory_required)

    models_to_load = []
    models_already_loaded = []
    for x in models:
        loaded_model = LoadedModel(x, memory_required=memory_required)

        if loaded_model in current_loaded_models:
            index = current_loaded_models.index(loaded_model)
            current_loaded_models.insert(0, current_loaded_models.pop(index))
            models_already_loaded.append(loaded_model)
        else:
            if hasattr(x, "model"):
                print(f"To load target model {x.model.__class__.__name__}")
            models_to_load.append(loaded_model)

    if len(models_to_load) == 0:
        devs = set(map(lambda a: a.device, models_already_loaded))
        for d in devs:
            if d != torch.device("cpu"):
                free_memory(extra_mem, d, models_already_loaded)

        moving_time = time.perf_counter() - execution_start_time
        if moving_time > 0.1:
            print(f'Memory cleanup has taken {moving_time:.2f} seconds')

        return

    print(f"Begin to load {len(models_to_load)} model{'s' if len(models_to_load) > 1 else ''}")

    total_memory_required = {}
    for loaded_model in models_to_load:
        unload_model_clones(loaded_model.model)
        total_memory_required[loaded_model.device] = total_memory_required.get(loaded_model.device, 0) + loaded_model.model_memory_required()

    for device in total_memory_required:
        if device != torch.device("cpu"):
            free_memory(total_memory_required[device] * 1.3 + extra_mem, device, models_already_loaded)

    for loaded_model in models_to_load:
        model = loaded_model.model
        torch_dev = model.load_device
        if is_device_cpu(torch_dev):
            vram_set_state = VRAMState.DISABLED
        else:
            vram_set_state = vram_state

        model_gpu_memory_when_using_cpu_swap = -1

        if lowvram_available and (vram_set_state == VRAMState.LOW_VRAM or vram_set_state == VRAMState.NORMAL_VRAM):
            model_memory = loaded_model.model_memory_required(torch_dev)
            current_free_mem = get_free_memory(torch_dev)
            inference_memory = minimum_inference_memory()
            estimated_remaining_memory = current_free_mem - model_memory - inference_memory

            print(f"[Memory Management] Current Free GPU Memory: {current_free_mem / (1024 * 1024):.2f} MB")
            print(f"[Memory Management] Required Model Memory: {model_memory / (1024 * 1024):.2f} MB")
            print(f"[Memory Management] Required Inference Memory: {inference_memory / (1024 * 1024):.2f} MB")
            print(f"[Memory Management] Estimated Remaining GPU Memory: {estimated_remaining_memory / (1024 * 1024):.2f} MB")

            if estimated_remaining_memory < 0:
                vram_set_state = VRAMState.LOW_VRAM
                model_gpu_memory_when_using_cpu_swap = compute_model_gpu_memory_when_using_cpu_swap(current_free_mem, inference_memory)

        if vram_set_state == VRAMState.NO_VRAM:
            model_gpu_memory_when_using_cpu_swap = 0

        loaded_model.model_load(model_gpu_memory_when_using_cpu_swap)
        current_loaded_models.insert(0, loaded_model)

    moving_time = time.perf_counter() - execution_start_time
    print(f'Moving model(s) has taken {moving_time:.2f} seconds')

    return


def load_model_gpu(model):
    return load_models_gpu([model])


def cleanup_models():
    to_delete = []
    for i in range(len(current_loaded_models)):
        if sys.getrefcount(current_loaded_models[i].model) <= 2:
            to_delete = [i] + to_delete

    for i in to_delete:
        x = current_loaded_models.pop(i)
        x.model_unload()
        del x


def dtype_size(dtype):
    dtype_size = 4
    if dtype == torch.float16 or dtype == torch.bfloat16:
        dtype_size = 2
    elif dtype == torch.float32:
        dtype_size = 4
    else:
        try:
            dtype_size = dtype.itemsize
        except:  # Old pytorch doesn't have .itemsize
            pass
    return dtype_size


def unet_offload_device():
    if vram_state == VRAMState.HIGH_VRAM:
        return get_torch_device()
    else:
        return torch.device("cpu")


def unet_inital_load_device(parameters, dtype):
    torch_dev = get_torch_device()
    if vram_state == VRAMState.HIGH_VRAM:
        return torch_dev

    cpu_dev = torch.device("cpu")
    if ALWAYS_VRAM_OFFLOAD:
        return cpu_dev

    model_size = dtype_size(dtype) * parameters

    mem_dev = get_free_memory(torch_dev)
    mem_cpu = get_free_memory(cpu_dev)
    if mem_dev > mem_cpu and model_size < mem_dev:
        return torch_dev
    else:
        return cpu_dev


def unet_dtype(device=None, model_params=0, supported_dtypes=[torch.float16, torch.bfloat16, torch.float32]):
    if args.unet_in_bf16:
        return torch.bfloat16

    if args.unet_in_fp16:
        return torch.float16

    if args.unet_in_fp8_e4m3fn:
        return torch.float8_e4m3fn

    if args.unet_in_fp8_e5m2:
        return torch.float8_e5m2

    for candidate in supported_dtypes:
        if candidate == torch.float16:
            if should_use_fp16(device=device, model_params=model_params, manual_cast=True):
                return candidate
        if candidate == torch.bfloat16:
            if should_use_bf16(device, model_params=model_params, manual_cast=True):
                return candidate

    return torch.float32


# None means no manual cast
def unet_manual_cast(weight_dtype, inference_device, supported_dtypes=[torch.float16, torch.bfloat16, torch.float32]):
    if weight_dtype == torch.float32:
        return None

    fp16_supported = should_use_fp16(inference_device, prioritize_performance=False)
    if fp16_supported and weight_dtype == torch.float16:
        return None

    bf16_supported = should_use_bf16(inference_device)
    if bf16_supported and weight_dtype == torch.bfloat16:
        return None

    if fp16_supported and torch.float16 in supported_dtypes:
        return torch.float16

    elif bf16_supported and torch.bfloat16 in supported_dtypes:
        return torch.bfloat16
    else:
        return torch.float32


def get_computation_dtype(inference_device, supported_dtypes=[torch.float16, torch.bfloat16, torch.float32]):
    for candidate in supported_dtypes:
        if candidate == torch.float16:
            if should_use_fp16(inference_device, prioritize_performance=False):
                return candidate
        if candidate == torch.bfloat16:
            if should_use_bf16(inference_device):
                return candidate

    return torch.float32


def text_encoder_offload_device():
    if args.always_gpu:
        return get_torch_device()
    else:
        return torch.device("cpu")


def text_encoder_device():
    if args.always_gpu:
        return get_torch_device()
    elif vram_state == VRAMState.HIGH_VRAM or vram_state == VRAMState.NORMAL_VRAM:
        if should_use_fp16(prioritize_performance=False):
            return get_torch_device()
        else:
            return torch.device("cpu")
    else:
        return torch.device("cpu")


def text_encoder_dtype(device=None):
    if args.clip_in_fp8_e4m3fn:
        return torch.float8_e4m3fn
    elif args.clip_in_fp8_e5m2:
        return torch.float8_e5m2
    elif args.clip_in_fp16:
        return torch.float16
    elif args.clip_in_fp32:
        return torch.float32

    if is_device_cpu(device):
        return torch.float16

    return torch.float16


def intermediate_device():
    if args.always_gpu:
        return get_torch_device()
    else:
        return torch.device("cpu")


def vae_device():
    if args.vae_in_cpu:
        return torch.device("cpu")
    return get_torch_device()


def vae_offload_device():
    if args.always_gpu:
        return get_torch_device()
    else:
        return torch.device("cpu")


def vae_dtype(device=None, allowed_dtypes=[]):
    global VAE_DTYPES
    if args.vae_in_fp16:
        return torch.float16
    elif args.vae_in_bf16:
        return torch.bfloat16
    elif args.vae_in_fp32:
        return torch.float32

    for d in allowed_dtypes:
        if d == torch.float16 and should_use_fp16(device, prioritize_performance=False):
            return d
        if d in VAE_DTYPES:
            return d

    return VAE_DTYPES[0]


print(f"VAE dtype preferences: {VAE_DTYPES} -> {vae_dtype()}")


def get_autocast_device(dev):
    if hasattr(dev, 'type'):
        return dev.type
    return "cuda"


def supports_dtype(device, dtype):  # TODO
    if dtype == torch.float32:
        return True
    if is_device_cpu(device):
        return False
    if dtype == torch.float16:
        return True
    if dtype == torch.bfloat16:
        return True
    return False


def supports_cast(device, dtype):  # TODO
    if dtype == torch.float32:
        return True
    if dtype == torch.float16:
        return True
    if directml_enabled:  # TODO: test this
        return False
    if dtype == torch.bfloat16:
        return True
    if is_device_mps(device):
        return False
    if dtype == torch.float8_e4m3fn:
        return True
    if dtype == torch.float8_e5m2:
        return True
    return False


def pick_weight_dtype(dtype, fallback_dtype, device=None):
    if dtype is None:
        dtype = fallback_dtype
    elif dtype_size(dtype) > dtype_size(fallback_dtype):
        dtype = fallback_dtype

    if not supports_cast(device, dtype):
        dtype = fallback_dtype

    return dtype


def device_supports_non_blocking(device):
    if is_device_mps(device):
        return False  # pytorch bug? mps doesn't support non blocking
    if is_intel_xpu():
        return False
    if args.pytorch_deterministic:  # TODO: figure out why deterministic breaks non blocking from gpu to cpu (previews)
        return False
    if directml_enabled:
        return False
    return True


def device_should_use_non_blocking(device):
    if not device_supports_non_blocking(device):
        return False
    return False
    # return True #TODO: figure out why this causes memory issues on Nvidia and possibly others


def force_channels_last():
    if args.force_channels_last:
        return True

    # TODO
    return False


def cast_to_device(tensor, device, dtype, copy=False):
    device_supports_cast = False
    if tensor.dtype == torch.float32 or tensor.dtype == torch.float16:
        device_supports_cast = True
    elif tensor.dtype == torch.bfloat16:
        if hasattr(device, 'type') and device.type.startswith("cuda"):
            device_supports_cast = True
        elif is_intel_xpu():
            device_supports_cast = True

    non_blocking = device_should_use_non_blocking(device)

    if device_supports_cast:
        if copy:
            if tensor.device == device:
                return tensor.to(dtype, copy=copy, non_blocking=non_blocking)
            return tensor.to(device, copy=copy, non_blocking=non_blocking).to(dtype, non_blocking=non_blocking)
        else:
            return tensor.to(device, non_blocking=non_blocking).to(dtype, non_blocking=non_blocking)
    else:
        return tensor.to(device, dtype, copy=copy, non_blocking=non_blocking)


def xformers_enabled():
    global directml_enabled
    global cpu_state
    if cpu_state != CPUState.GPU:
        return False
    if is_intel_xpu():
        return False
    if directml_enabled:
        return False
    return XFORMERS_IS_AVAILABLE


def xformers_enabled_vae():
    enabled = xformers_enabled()
    if not enabled:
        return False

    return XFORMERS_ENABLED_VAE


def pytorch_attention_enabled():
    global ENABLE_PYTORCH_ATTENTION
    return ENABLE_PYTORCH_ATTENTION


def pytorch_attention_flash_attention():
    global ENABLE_PYTORCH_ATTENTION
    if ENABLE_PYTORCH_ATTENTION:
        # TODO: more reliable way of checking for flash attention?
        if is_nvidia():  # pytorch flash attention only works on Nvidia
            return True
        if is_intel_xpu():
            return True
    return False


def force_upcast_attention_dtype():
    upcast = args.force_upcast_attention
    try:
        if platform.mac_ver()[0] in ['14.5']:  # black image bug on OSX Sonoma 14.5
            upcast = True
    except:
        pass
    if upcast:
        return torch.float32
    else:
        return None


def get_free_memory(dev=None, torch_free_too=False):
    global directml_enabled
    if dev is None:
        dev = get_torch_device()

    if hasattr(dev, 'type') and (dev.type == 'cpu' or dev.type == 'mps'):
        mem_free_total = psutil.virtual_memory().available
        mem_free_torch = mem_free_total
    else:
        if directml_enabled:
            mem_free_total = 1024 * 1024 * 1024
            mem_free_torch = mem_free_total
        elif is_intel_xpu():
            stats = torch.xpu.memory_stats(dev)
            mem_active = stats['active_bytes.all.current']
            mem_reserved = stats['reserved_bytes.all.current']
            mem_free_torch = mem_reserved - mem_active
            mem_free_xpu = torch.xpu.get_device_properties(dev).total_memory - mem_reserved
            mem_free_total = mem_free_xpu + mem_free_torch
        else:
            stats = torch.cuda.memory_stats(dev)
            mem_active = stats['active_bytes.all.current']
            mem_reserved = stats['reserved_bytes.all.current']
            mem_free_cuda, _ = torch.cuda.mem_get_info(dev)
            mem_free_torch = mem_reserved - mem_active
            mem_free_total = mem_free_cuda + mem_free_torch

    if torch_free_too:
        return (mem_free_total, mem_free_torch)
    else:
        return mem_free_total


def cpu_mode():
    global cpu_state
    return cpu_state == CPUState.CPU


def mps_mode():
    global cpu_state
    return cpu_state == CPUState.MPS


def is_device_type(device, type):
    if hasattr(device, 'type'):
        if (device.type == type):
            return True
    return False


def is_device_cpu(device):
    return is_device_type(device, 'cpu')


def is_device_mps(device):
    return is_device_type(device, 'mps')


def is_device_cuda(device):
    return is_device_type(device, 'cuda')


def should_use_fp16(device=None, model_params=0, prioritize_performance=True, manual_cast=False):
    global directml_enabled

    if device is not None:
        if is_device_cpu(device):
            return False

    if FORCE_FP16:
        return True

    if device is not None:
        if is_device_mps(device):
            return True

    if FORCE_FP32:
        return False

    if directml_enabled:
        return False

    if mps_mode():
        return True

    if cpu_mode():
        return False

    if is_intel_xpu():
        return True

    if torch.version.hip:
        return True

    props = torch.cuda.get_device_properties("cuda")
    if props.major >= 8:
        return True

    if props.major < 6:
        return False

    fp16_works = False
    # FP16 is confirmed working on a 1080 (GP104) but it's a bit slower than FP32 so it should only be enabled
    # when the model doesn't actually fit on the card
    # TODO: actually test if GP106 and others have the same type of behavior
    nvidia_10_series = ["1080", "1070", "titan x", "p3000", "p3200", "p4000", "p4200", "p5000", "p5200", "p6000", "1060", "1050", "p40", "p100", "p6", "p4"]
    for x in nvidia_10_series:
        if x in props.name.lower():
            fp16_works = True

    if fp16_works or manual_cast:
        free_model_memory = (get_free_memory() * 0.9 - minimum_inference_memory())
        if (not prioritize_performance) or model_params * 4 > free_model_memory:
            return True

    if props.major < 7:
        return False

    # FP16 is just broken on these cards
    nvidia_16_series = ["1660", "1650", "1630", "T500", "T550", "T600", "MX550", "MX450", "CMP 30HX", "T2000", "T1000", "T1200"]
    for x in nvidia_16_series:
        if x in props.name:
            return False

    return True


def should_use_bf16(device=None, model_params=0, prioritize_performance=True, manual_cast=False):
    if device is not None:
        if is_device_cpu(device):  # TODO ? bf16 works on CPU but is extremely slow
            return False

    if device is not None:
        if is_device_mps(device):
            return True

    if FORCE_FP32:
        return False

    if directml_enabled:
        return False

    if mps_mode():
        return True

    if cpu_mode():
        return False

    if is_intel_xpu():
        return True

    if device is None:
        device = torch.device("cuda")

    props = torch.cuda.get_device_properties(device)
    if props.major >= 8:
        return True

    bf16_works = torch.cuda.is_bf16_supported()

    if bf16_works or manual_cast:
        free_model_memory = (get_free_memory() * 0.9 - minimum_inference_memory())
        if (not prioritize_performance) or model_params * 4 > free_model_memory:
            return True

    return False


def can_install_bnb():
    try:
        if not torch.cuda.is_available():
            return False

        cuda_version = tuple(int(x) for x in torch.version.cuda.split('.'))

        if cuda_version >= (11, 7):
            return True

        return False
    except:
        return False


def soft_empty_cache(force=False):
    global cpu_state
    if cpu_state == CPUState.MPS:
        torch.mps.empty_cache()
    elif is_intel_xpu():
        torch.xpu.empty_cache()
    elif torch.cuda.is_available():
        if force or is_nvidia():  # This seems to make things worse on ROCm so I only do it for cuda
            torch.cuda.empty_cache()
            torch.cuda.ipc_collect()


def unload_all_models():
    free_memory(1e30, get_torch_device())


def resolve_lowvram_weight(weight, model, key):  # TODO: remove
    return weight


# TODO: might be cleaner to put this somewhere else
import threading


class InterruptProcessingException(Exception):
    pass


interrupt_processing_mutex = threading.RLock()

interrupt_processing = False


def interrupt_current_processing(value=True):
    global interrupt_processing
    global interrupt_processing_mutex
    with interrupt_processing_mutex:
        interrupt_processing = value


def processing_interrupted():
    global interrupt_processing
    global interrupt_processing_mutex
    with interrupt_processing_mutex:
        return interrupt_processing


def throw_exception_if_processing_interrupted():
    global interrupt_processing
    global interrupt_processing_mutex
    with interrupt_processing_mutex:
        if interrupt_processing:
            interrupt_processing = False
            raise InterruptProcessingException()