docs/env_vars.md
This is a list of environment variable that control the runtime behavior of tinygrad and its examples. Most of these are self-explanatory, and are usually used to set an option at runtime.
Example: CL=1 DEBUG=4 python3 -m pytest
However you can also decorate a function to set a value only inside that function.
# in tensor.py (probably only useful if you are a tinygrad developer)
@Context(DEBUG=4)
def numpy(self) -> ...
Or use contextmanager to temporarily set a value inside some scope:
with Context(DEBUG=0):
a = Tensor.ones(10, 10)
a *= 2
The columns of this list are are: Variable, Possible Value(s) and Description.
# means that the variable can take any integer value.These control the behavior of core tinygrad even when used as a library.
| Variable | Possible Value(s) | Description |
|---|---|---|
| DEBUG | [1-7] | enable debugging output (operations, timings, speed, generated code and more) |
| CL | [1] | enable OpenCL backend |
| CUDA | [1] | enable CUDA backend |
| AMD | [1] | enable AMD backend |
| NV | [1] | enable NV backend |
| METAL | [1] | enable Metal backend (for Mac M1 and after) |
| CPU | [1] | enable CPU backend |
| BEAM | [#] | number of beams in kernel beam search |
| DEFAULT_FLOAT | [HALF, ...] | specify the default float dtype (FLOAT32, HALF, BFLOAT16, FLOAT64, ...), default to FLOAT32 |
| IMAGE | [1-2] | enable 2d specific optimizations |
| FLOAT16 | [1] | use float16 for images instead of float32 |
| HCQ_VISIBLE_DEVICES | [list[int]] | restricts the HCQ devices that are available. The format is a comma-separated list of identifiers (indexing starts with 0). |
| JIT | [0-2] | 0=disabled, 1=jit enabled (default), 2=jit enabled, but graphs are disabled |
| VIZ | [1] | 0=disabled, 1=viz enabled |
| ALLOW_TF32 | [1] | enable TensorFloat-32 tensor cores on Ampere or newer GPUs. |
| WEBGPU_BACKEND | [WGPUBackendType_Metal, ...] | Force select a backend for WebGPU (Metal, DirectX, OpenGL, Vulkan...) |
| CUDA_PATH | str | Use CUDA_PATH/include for CUDA headers for CUDA and NV backends. If not set, TinyGrad will use /usr/local/cuda/include, /usr/include and /opt/cuda/include. |
| Variable | Value | Description |
|---|---|---|
| DEBUG | >= 1 | Enables debugging and lists devices being used |
| DEBUG | >= 2 | Provides performance metrics for operations, including timing, memory usage, bandwidth for each kernel execution |
| DEBUG | >= 3 | Outputs buffers used for each kernel (shape, dtype and strides) and the applied optimizations at a kernel level |
| DEBUG | >= 4 | Outputs the generated kernel code |
| DEBUG | >= 5 | Displays the intermediate representation of the computation UOps (AST) |
| DEBUG | >= 6 | Displays the intermediate representation of the computation UOps in a linearized manner, detailing the operation sequence |
| DEBUG | >= 7 | Outputs the assembly code generated for the target hardware |