# npu-probe

Smallest-possible userspace binary that:
1. Opens the NPU device (path TBD per Phase-1 audit)
2. Allocates two INT8 input tensors (64×64) + one output (64×64)
3. Submits a matmul via the uAPI in use (Tomeu's accel ioctl OR our own
   shim around vendor MMIO if accel-mainline isn't ready)
4. Waits for completion (DMA fence or polled completion register)
5. Reads back the output
6. Compares to a CPU INT8 matmul reference; reports pass/fail

**Phase-1 deliverable.** Until this works, nothing else in this repo
can be exercised against real silicon.

## Build

_(filled when Phase-1 audit picks the uAPI shape — `meson` or `cmake`,
no autotools)_

## Run

```
./npu-probe                      # default 64×64 INT8 matmul
./npu-probe --shape 128,128,128  # M,N,K override
./npu-probe --device /dev/accel/accel0    # override device path
./npu-probe --golden golden_64x64.bin     # provide expected output for diff
```

## Why C, not Python

Direct ioctl + dmabuf + mmap. Python wrapper layer would obscure the
exact syscall sequence we need to understand. Once npu-probe works,
a Python binding for benchmark scripts is fine.