# mypy: allow-untyped-defs # mypy: disable-error-code="method-assign" """ Debug utilities for TorchDynamo compilation and execution. This module provides various debugging tools and utilities for TorchDynamo, including: - Minification support for reducing test cases while preserving bugs - Input/output handling via InputReader and InputWriter for reproducible testing - Accuracy checking between original and compiled models - Neural network module string conversion via NNModuleToString - Profiling tools and system information collection - Buck build system integration for Meta-internal testing Key classes: - InputReader/InputWriter: Handle serialization of model inputs/outputs - NNModuleToString: Converts nn.Modules to string representations - BuckTargetWriter: Manages Buck build system integration """ import atexit import copy import cProfile import functools import getpass import inspect import itertools import logging import os import re import subprocess import sys import tempfile import textwrap from collections import Counter from importlib import import_module from typing import Any, Callable, Optional, TypeVar import torch import torch._prims_common as utils import torch._subclasses.meta_utils from torch import Tensor from torch._dynamo.testing import rand_strided from torch._prims_common import is_float_dtype from torch.multiprocessing.reductions import StorageWeakRef from torch.utils._content_store import ContentStoreReader, ContentStoreWriter from . import config from .utils import clone_inputs, get_debug_dir log = logging.getLogger(__name__) T = TypeVar("T") inductor_config = import_module("torch._inductor.config") use_buck = inductor_config.is_fbcode() if use_buck: import libfb.py.build_info extra_deps = [] extra_imports = "" if use_buck: extra_deps = [ "//caffe2/torch/fb/sparsenn:sparsenn_operators_gpu", "//caffe2/torch/fb/sparsenn:sparsenn_operators", "//deeplearning/fbgemm/fbgemm_gpu:sparse_ops_cpu", "//deeplearning/fbgemm/fbgemm_gpu:sparse_ops", ] cur_target = libfb.py.build_info.BuildInfo.get_build_rule().replace("fbcode:", "//") # type: ignore[possibly-undefined] extra_imports = "\n".join([f'torch.ops.load_library("{x}")' for x in extra_deps]) BUCK_CMD_PREFIX = ["buck2", "run", "@mode/dev-nosan"] class BuckTargetWriter: def __init__(self, filename): self.subdir, self.py_file = os.path.split(os.path.abspath(filename)) self.target = self.py_file.replace(".py", "") # Get main_module path from fbcode self.path = f"{self.subdir.replace('/', '.')}.{self.target}" self.path = self.path[self.path.find("fbcode.") :] self.path = self.path[7:] # Get cmd line path tmp = self.subdir tmp = tmp[tmp.find("fbcode/") :][7:] self.cmd_line_path = f"//{tmp}:{self.target}" def build(self): extra_cpp_deps = "\n".join([f' "{x}",' for x in extra_deps]) return textwrap.dedent( f""" load("@fbcode_macros//build_defs:python_binary.bzl", "python_binary") python_binary( name="{self.target}", srcs = ["{self.py_file}"], compile = False, deps = [ "//caffe2:torch", "//caffe2:libtorch", "//caffe2/functorch:functorch", "//triton:triton", "{cur_target}", ], cpp_deps = [ {extra_cpp_deps} ], main_module = "{self.path}", par_style = "xar", ) """ ) def write(self, print_msg=True): target_file = os.path.join(self.subdir, "TARGETS") with open(target_file, "w") as fd: fd.write(self.build()) # log.warning("Wrote isolation TARGETS file at %s", target_file) cmd_split = BUCK_CMD_PREFIX + [self.cmd_line_path] if print_msg: log.warning( "Found an example that reproduces the error. Run this cmd to repro - %s", " ".join(cmd_split), ) return cmd_split def minifier_dir(): path = os.path.join(get_debug_dir(), "minifier") if path is None: path = f"{tempfile.gettempdir()}/minifier_{getpass.getuser()}" if not os.path.exists(path): os.makedirs(path, exist_ok=True) return path MAX_CONSTANT_NUMEL_INLINE = 4 class NNModuleToString: safe_reprs = [ torch.nn.Linear, torch.nn.Conv1d, torch.nn.Conv2d, torch.nn.Conv3d, torch.nn.BatchNorm1d, torch.nn.BatchNorm2d, torch.nn.BatchNorm3d, torch.nn.LayerNorm, torch.nn.Dropout, torch.nn.Softmax, torch.nn.ReLU, torch.nn.GELU, torch.nn.Identity, torch.nn.MaxPool2d, torch.nn.Embedding, torch.nn.Tanh, torch.nn.ConvTranspose1d, torch.nn.GLU, torch.nn.LSTM, torch.nn.Flatten, torch.nn.AdaptiveAvgPool2d, ] @staticmethod def can_convert_to_string(gm): cant_convert = set() for _, module in gm.named_children(): if type(module) not in NNModuleToString.safe_reprs: cant_convert.add(module) if len(cant_convert) > 0: log.warning("We have not tested reprs of some modules - %s", cant_convert) # TODO - Assuming that all modules can be safely repr'd. Check if that assumption is correct. return True @staticmethod def convert(gm): from torch.nn.modules.module import _addindent tab = " " * 4 model_str = textwrap.dedent( """ from torch.nn import * class Repro(torch.nn.Module): def __init__(self) -> None: super().__init__() """ ) for module_name, module in gm.named_children(): module_str = f"{module.__repr__()}" # module should be a core torch.nn.Module, so all parameters # should be on the same device. example_param = next(module.parameters(), None) if example_param is not None and example_param.is_cuda: module_str = f"{module_str}.cuda()" model_str += f"{tab * 2}self.{module_name} = {module_str}\n" for buffer_name, buffer in gm._buffers.items(): if buffer is None: continue # Serialize full data for small buffers if buffer.numel() <= MAX_CONSTANT_NUMEL_INLINE: from torch._tensor_str import PRINT_OPTS assert PRINT_OPTS.threshold >= MAX_CONSTANT_NUMEL_INLINE tensor_str = repr(buffer) elif torch.is_floating_point(buffer): tensor_str = f"torch.randn({list(buffer.shape)}, dtype={buffer.dtype})" else: tensor_str = ( f"torch.randint(1, size={list(buffer.shape)}, dtype={buffer.dtype})" ) if buffer.is_cuda: tensor_str = f"{tensor_str}.cuda()" model_str += ( f"{tab * 2}self.register_buffer('{buffer_name}', {tensor_str})\n" ) for param_name, param in gm._parameters.items(): if param is None: continue maybe_device = "" if param.is_cuda: maybe_device = ', device="cuda"' tensor_str = f"torch.nn.Parameter(torch.randn({list(param.shape)}, dtype={param.dtype}{maybe_device}))" model_str += f"{tab * 2}self.{param_name} = {tensor_str}\n" # TODO - Keep this code for now. But, I don't think we will need this. # attrs = dir(gm) # for attr in attrs: # if "_tensor_constant" in attr: # val = getattr(gm, attr) # model_str += f" {attr} = {val!r}\n" model_str += f"{_addindent(gm.code, 4)}\n" return model_str @functools.lru_cache(None) # subprocess is expensive def _cuda_system_info_comment(): if not torch.cuda.is_available(): return "# torch.cuda.is_available()==False, no GPU info collected\n" model_str = "# CUDA Info: \n" try: cuda_version_out = subprocess.check_output(["nvcc", "--version"]) cuda_version_lines = cuda_version_out.decode().split("\n") comment = "".join([f"# {s} \n" for s in cuda_version_lines if s not in [""]]) model_str += f"{comment}\n" except (FileNotFoundError, subprocess.CalledProcessError): model_str += "# nvcc not found\n" gpu_names = Counter( torch.cuda.get_device_name(i) for i in range(torch.cuda.device_count()) ) model_str += "# GPU Hardware Info: \n" for name, count in gpu_names.items(): model_str += f"# {name} : {count} \n" model_str += "\n" return model_str def generate_env_vars_string(*, stable_output=False): """ Generate a string configuration for environment variables related to Dynamo, Inductor, and Triton. """ if stable_output: return "# env var omitted due to stable_output=True" allow_list = ["TORCH", "DYNAMO", "INDUCTOR", "TRITON"] skip_list = ["TRITON_LIBDEVICE_PATH", "TRITON_PTXAS_PATH", "TRITON_LIBCUDA_PATH"] def filter(key): return any(string in key for string in allow_list) and key not in skip_list config_lines = [ f"os.environ['{key}'] = '{value}'" for key, value in os.environ.items() if filter(key) ] config_string = "\n".join(config_lines) return f"""\ import os {config_string} """ def generate_config_string(*, stable_output=False): import torch._functorch.config import torch._inductor.config if stable_output: return "# config omitted due to stable_output=True" experimental_config = torch.fx.experimental._config.codegen_config() # type: ignore[attr-defined] return f"""\ import torch._dynamo.config import torch._inductor.config import torch._functorch.config import torch.fx.experimental._config {torch._dynamo.config.codegen_config()} {torch._inductor.config.codegen_config()} {torch._functorch.config.codegen_config()} {experimental_config} """ def get_minifier_repro_path(): return os.path.join(minifier_dir(), "minifier_launcher.py") def helper_for_dump_minify(contents): minified_repro_path = get_minifier_repro_path() log.warning("Writing minified repro to:\n%s", minified_repro_path) if use_buck: BuckTargetWriter(minified_repro_path).write() try: with open(minified_repro_path, "w") as fd: fd.write(contents) except OSError as e: log.exception("") raise NotImplementedError("Could not write to {minified_repro_path}") from e class AccuracyError(Exception): pass def clone_inputs_retaining_gradness(example_inputs): """ This clone inputs is different from utils clone_input. In case of minifier, all the tensors are leaf tensors while creating a new graph. So, we set the requires_grad field w/o checking the leafness of the tensor. """ cloned_inputs = clone_inputs(example_inputs) for idx in range(len(example_inputs)): if isinstance(cloned_inputs[idx], torch.Tensor): cloned_inputs[idx].requires_grad_(example_inputs[idx].requires_grad) return cloned_inputs def run_fwd_maybe_bwd(gm, args, only_fwd=False, disable_clone=False): """ Runs a forward and possibly backward iteration for a given mod and args. When disable_clone is True, we will use args as-is without cloning. This is higher fidelity but we may destroy the args in the process. """ from .testing import collect_results, reduce_to_scalar_loss, requires_bwd_pass gm = copy.deepcopy(gm) if not disable_clone: args = clone_inputs_retaining_gradness(args) if hasattr(gm, "zero_grad"): gm.zero_grad(True) # TorchInductor returned callable expects lists. So, may need a boxed calling convention. out = gm(args) if hasattr(gm, "_boxed_call") else gm(*args) if only_fwd: return out if requires_bwd_pass(out): loss = reduce_to_scalar_loss(out) loss.backward() return collect_results(gm, out, None, args) def same_two_models( gm, opt_gm, example_inputs, only_fwd=False, *, require_fp64=False, ignore_non_fp=False, ): """ Check two models have same accuracy. require_fp64: if True, raise an error if we unable to calculate the fp64 reference ignore_non_fp: if True, do not compare outputs which are not floating point. This is mostly useful for the minifier (which wants to avoid quantizing floating point error into integer/boolean error) """ from .utils import same ref = run_fwd_maybe_bwd(gm, example_inputs, only_fwd) fp64_ref = None if config.same_two_models_use_fp64: try: fp64_model, fp64_examples = cast_to_fp64( copy.deepcopy(gm), clone_inputs_retaining_gradness(example_inputs) ) fp64_ref = run_fwd_maybe_bwd(fp64_model, fp64_examples, only_fwd) except Exception: if require_fp64: raise RuntimeError( # noqa: B904 "Could not generate fp64 outputs, workaround with torch._dynamo.config.same_two_models_use_fp64 = False" ) log.warning("Could not generate fp64 outputs") try: res = run_fwd_maybe_bwd(opt_gm, example_inputs, only_fwd) except Exception: # This means that the minified graph is bad/exposes a different problem. # As we are checking accuracy here, lets log the exception and return True. log.exception( "While minifying the program in accuracy minification mode, " "ran into a runtime exception which is likely an unrelated issue." " Skipping this graph." ) return True passing = same( ref, res, fp64_ref, tol=config.repro_tolerance, equal_nan=True, ignore_non_fp=ignore_non_fp, ) return passing def cast_dtype_args_to_fp64(model): for node in model.graph.nodes: if ( node.op == "call_function" and node.target == torch.ops.prims.convert_element_type.default ): assert len(node.args) == 2 if is_float_dtype(node.args[1]) and node.args[1] != torch.float64: node.args = (node.args[0], torch.float64) if node.op == "call_function": dtype = node.kwargs.get("dtype") if dtype is not None and is_float_dtype(dtype): new_kwargs = dict(node.kwargs) new_kwargs["dtype"] = torch.float64 node.kwargs = new_kwargs model.graph.lint() model.recompile() return model def cast_to(dtype, model, inputs): from torch.utils._pytree import tree_map model = model.to(dtype) if dtype == torch.float64: # If casting to fp64 for accuracy comparison, we need to # replace dtype arguments embedded in the graph with fp64 model = cast_dtype_args_to_fp64(model) inputs = tree_map( lambda x: x.to(dtype) if isinstance(x, torch.Tensor) and x.is_floating_point() else x, inputs, ) return model, inputs def cast_to_fp64(model, inputs): return cast_to(torch.float64, model, inputs) def backend_accuracy_fails( gm, example_inputs, compiler_fn, only_fwd=False, *, require_fp64=False, ignore_non_fp=False, ): try: compiled_gm = compiler_fn( copy.deepcopy(gm), clone_inputs_retaining_gradness(example_inputs) ) return not same_two_models( gm, compiled_gm, example_inputs, only_fwd, require_fp64=require_fp64, ignore_non_fp=ignore_non_fp, ) except Exception: # This means that the minified graph is bad/exposes a different problem. # As we are checking accuracy here, lets log the exception and return False. log.exception( "While minifying the program in accuracy minification mode, " "ran into a runtime exception which is likely an unrelated issue." " Skipping this graph" ) return False # ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ # # REPRO SUPPORT CODE # ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ # # Helper functions for computing what the default values of tensor # values should be. These all coincide with factory functions, e.g., torch.empty def _stride_or_default( stride: Optional["torch._prims_common.StrideType"], *, shape: "torch._prims_common.ShapeType", ) -> "torch._prims_common.StrideType": return stride if stride is not None else utils.make_contiguous_strides_for(shape) def _mk_defaulter(d: T) -> Callable[[Optional[T]], T]: return lambda x: x if x is not None else d _dtype_or_default = _mk_defaulter(torch.float32) _device_or_default = _mk_defaulter(torch.device("cpu")) _storage_offset_or_default = _mk_defaulter(0) _requires_grad_or_default = _mk_defaulter(False) _is_leaf_or_default = _mk_defaulter(False) class NopInputReader: def __init__(self) -> None: self.total = 0 def storage(self, storage_hash, nbytes, *, device=None, dtype_hint=None): self.total += 1 def tensor(self, *args, **kwargs): pass def symint(self, *args, **kwargs): pass # TODO: Support bundling the entire repro into a zip file for ease of # transferring around class InputReader: def __init__(self, save_dir=None, *, pbar=None): # If None, we will generate random data instead. It's important # to natively support this use case as it will allow people to # share repros without including the real data, if the problem # reproduces even on random data. if save_dir is None: log.warning("no save_dir specified, will generate random data") self.store = ContentStoreReader(save_dir) if save_dir is not None else None self.args = [] self.pbar = pbar def storage(self, storage_hash, nbytes, *, device=None, dtype_hint=None): if self.pbar is not None: self.pbar.update(1) device = _device_or_default(device) dtype_hint = _dtype_or_default(dtype_hint) if self.store is not None and storage_hash is not None: try: storage = self.store.read_storage(storage_hash) except FileNotFoundError: pass else: if device != storage.device: log.warning("device mismatch: %s != %s", device, storage.device) # TODO: transfer it to the right device? But failing this # way would be very mysterious! Would have been better # not to store device in the serialized format... return storage log.warning("could not load %s, generating random data instead", storage_hash) shape = (nbytes // dtype_hint.itemsize,) stride = _stride_or_default(None, shape=shape) return rand_strided(shape, stride, dtype_hint, device).untyped_storage() def tensor( self, storage, shape, stride=None, *, storage_offset=None, dtype=None, requires_grad=None, is_leaf=None, **metadata, ): stride = _stride_or_default(stride, shape=shape) storage_offset = _storage_offset_or_default(storage_offset) dtype = _dtype_or_default(dtype) is_leaf = _is_leaf_or_default(is_leaf) requires_grad = _requires_grad_or_default(requires_grad) t = torch.tensor( [], dtype=dtype, device=storage.device, requires_grad=requires_grad ) with torch.no_grad(): t.set_(storage, storage_offset, shape, stride) if not is_leaf: # Fake up some autograd history in a very naughty way with torch.enable_grad(): t = t.clone(memory_format=torch.preserve_format) with torch.no_grad(): t.set_(storage, storage_offset, shape, stride) assert torch._subclasses.meta_utils.safe_is_leaf(t) == is_leaf torch._utils.set_tensor_metadata(t, metadata) self.args.append(t) return t # for BC def symint(self, val): self.args.append(val) return val # for BC # Here is our writer strategy: # 1. We will stream all of the inputs to disk # 2. You can now deterministically randomize the inputs, or reload # the inputs from disk # 3. You can YOLO run the script without the inputs, in which case # we'll fill the inputs with random data and pray. This is the # legacy behavior, but it's also useful if you want to find out # if we're so broken even random inputs trigger it # 4. We could offer an in process "check if the randomized thing # works too" but this is delicate so we don't do it class InputWriter: def __init__(self, save_dir, *, stable_hash=False): self._lines = [] # TODO: consider ensuring tensor and storage counters line up? self.storage_counter = itertools.count() self.save_dir = save_dir self.store = ( ContentStoreWriter(save_dir, stable_hash=stable_hash) if save_dir is not None else None ) self.seen_storages = {} def lines(self): r = [ "def load_args(reader):", ] r.extend(f" {l}" for l in self._lines) # In case we need to change the internal format of load_args # in an FC-breaking way r.append("load_args._version = 0") return r # Storages are untyped, but we need to initialize them with data if # we don't have the real data, so we give a hint saying what kind # of initialization may be appropriate # # If we had a FakeTensor, device_hint tells us what device should be def storage(self, untyped_storage, *, dtype_hint=None, device_hint=None) -> str: ws = StorageWeakRef(untyped_storage) v = self.seen_storages.get(ws) if v is not None: return v v = f"buf{next(self.storage_counter)}" maybe_dtype_hint = "" if _dtype_or_default(None) != _dtype_or_default(dtype_hint): maybe_dtype_hint = f", dtype_hint={dtype_hint!r}" # TODO: being optional on device is kind of pointless as the default # is CPU but most repros we care about are CUDA maybe_device = "" device = untyped_storage.device if device.type == "meta": assert device_hint is not None device = device_hint if _device_or_default(None) != device: maybe_device = f", device={device!r}" nbytes = untyped_storage.nbytes() storage_hash = None if self.store is not None and untyped_storage.device.type != "meta": storage_hash = self.store.write_storage(untyped_storage) self._lines.append( f"{v} = reader.storage({storage_hash!r}, {nbytes!r}{maybe_device}{maybe_dtype_hint})" ) self.seen_storages[ws] = v return v def tensor(self, name, t) -> None: from torch.fx.experimental.symbolic_shapes import statically_known_true, sym_eq storage = self.storage( t.untyped_storage(), dtype_hint=t.dtype, device_hint=t.device ) args = [] # NB: this is positional, must come first if not statically_known_true( sym_eq(_stride_or_default(None, shape=t.shape), t.stride()) ): args.append(str(tuple(t.stride()))) if _dtype_or_default(None) != t.dtype: args.append(f"dtype={t.dtype!r}") if not statically_known_true( _storage_offset_or_default(None) == t.storage_offset() ): args.append(f"storage_offset={t.storage_offset()!r}") tensor_metadata = torch._utils.get_tensor_metadata(t) if tensor_metadata: args.extend(f"{k}={v!r}" for k, v in tensor_metadata.items()) if _requires_grad_or_default(None) != t.requires_grad: args.append(f"requires_grad={t.requires_grad!r}") is_leaf = torch._subclasses.meta_utils.safe_is_leaf(t) if _is_leaf_or_default(None) != is_leaf: args.append(f"is_leaf={is_leaf!r}") self._lines.append( "reader.tensor(" + ", ".join([storage, str(tuple(t.shape)), *args]) + f") # {name}" ) def unsupported(self, name, arg): # NB: Try hard not to /print/ a tensor, that will be very slow self._lines.append(f"# {name} was unsupported type for dumping: {type(arg)}") # Best effort dump as much useful stuff we can lol, in case you want # to repair the repro if isinstance(arg, (list, tuple)): self._lines.append('"""') for i, a in enumerate(arg): name_i = f"{name}[{i}]" if isinstance(a, torch.Tensor): self.tensor(name_i, a) elif isinstance(a, (int, torch.SymInt)): self.symint(name_i, a) else: self.unsupported(name_i, a) self._lines.append('"""') # write out that the arg was filtered out as it is constant def const(self, name) -> None: self._lines.append( f"reader.const({name!r}) # {name}, filtered out during compilation" ) # TODO: this doesn't actually symint atm def symint(self, name, val) -> None: if isinstance(val, torch.SymInt): val = val.node.hint self._lines.append(f"reader.symint({val!r}) # {name}") def aot_graph_input_parser( func: Callable[[list[Tensor]], list[Tensor]], device: str = "cuda", sym_shapes: Optional[dict[str, int]] = None, default_sym_shape: Optional[int] = None, ) -> dict[str, Any]: """ Takes in a function which has been printed with print_readable() and constructs kwargs to run it. Handles Tensor inputs, Symints, and a graph module which might have tensor constants. Consider a function `forward` defined as follows: def forward(self, primals_1: "f32[1001, 6]", primals_2: "f32[s0]", primals_3: "Sym(s0)",): _tensor_constant0: "i64[4190]" = self._tensor_constant0 # Further implementation kwargs = aot_graph_input_parser(forward) forward(**kwargs) """ from torch.fx.graph import dtype_abbrs dtype_map = {value: key for key, value in dtype_abbrs.items()} dtype_pattern = "|".join(dtype_abbrs.values()) # Extracting the source code from the function source = inspect.getsource(func) # Regular expressions tensor_assignment_regex = rf"(_tensor_constant\d+): \"({dtype_pattern})\[\s*(.*?)\s*\]\" = self\.(_tensor_constant\d+)" tensor_regex = rf"({dtype_pattern})\[\s*(.*?)\s*\]" sym_shape_regex = r"Sym\((s\d+)\)" class TensorContainer: "Container for tensors as attributes" # Dictionary for tensors from annotations kwargs: dict[str, Any] = {} sym_shapes = sym_shapes or {} def get_sym_int(symint): torch._check( symint in sym_shapes or default_sym_shape is not None, lambda: f"{symint} not in symbolic_shapes and default sym shape not passed in", ) return sym_shapes.get(symint, default_sym_shape) def gen_tensor(shape, dtype) -> Tensor: # Resolve symbolic shapes to concrete values resolved_shape = [] dynamic_dims = [] for i, dim in enumerate(shape): dim = dim.strip() if "s" in dim: s = get_sym_int(dim) resolved_shape.append(s) dynamic_dims.append(i) else: if dim: resolved_shape.append(int(dim)) constructor = torch.randn if dtype.is_floating_point else torch.zeros out = constructor(resolved_shape, dtype=dtype, device=device) # type: ignore[call-arg] for d in dynamic_dims: torch._dynamo.mark_dynamic(out, d) return out # Parse function annotations for tensor generation annotations = func.__annotations__ for param, annotation in annotations.items(): # Skip 'return' annotation if param == "return": continue match = re.search(tensor_regex, annotation) if match: data_type, shape_str = match.groups() shape = tuple(shape_str.split(",")) dtype = dtype_map[data_type] kwargs[param] = gen_tensor(shape, dtype) match = re.search(sym_shape_regex, annotation) if match: kwargs[param] = get_sym_int(match.group(1)) if "self" in inspect.signature(func).parameters: container = TensorContainer() kwargs["self"] = container for match in re.finditer(tensor_assignment_regex, source): attr_name, data_type, shape_str, _ = match.groups() shape = tuple(shape_str.split(",")) dtype = dtype_map[data_type] setattr(container, attr_name, gen_tensor(shape, dtype)) return kwargs def profile_to_file(filename: str) -> Callable[[T], T]: """ Decorator to cProfile a given function and save the result to disk on process exit. Args: filename: filename to save profile to """ prof = cProfile.Profile() filename = os.path.abspath(os.path.expanduser(filename)) def decorator(fn): @functools.wraps(fn) def wrapper(*args, **kwargs): prof.enable() try: return fn(*args, **kwargs) finally: prof.disable() return wrapper def save_it(): prof.dump_stats(filename) sys.stderr.write( textwrap.dedent( f"""\ Wrote profile to {filename}, view with: snakeviz {filename} """ ) ) atexit.register(save_it) return decorator