fix commavq benchmark (#4712)

* fix _slice and assert explicit device

* with _slice

test/external/external_model_benchmark.py

@@ -1,5 +1,6 @@
 import csv, pathlib, time, numpy as np
 from os import getenv
+from tinygrad.device import CompileError
 import torch
 torch.set_num_threads(1)
 import onnx
@@ -60,8 +61,8 @@ def benchmark_model(m, devices, validate_outs=False):
 
   # print input names
   if DEBUG >= 2: print([inp.name for inp in onnx_model.graph.input if inp.name not in excluded])
-  try:
-    for device in devices:
+  for device in devices:
+    try:
       Device.DEFAULT = device
       inputs = {k:Tensor(inp) for k,inp in np_inputs.items()}
       tinygrad_model = get_run_onnx(onnx_model)
@@ -72,10 +73,10 @@ def benchmark_model(m, devices, validate_outs=False):
       for _ in range(3): {k:v.numpy() for k,v in tinygrad_jitted_model(**inputs).items()}
       benchmark(m, f"tinygrad_{device.lower()}_jit", lambda: {k:v.numpy() for k,v in tinygrad_jitted_model(**inputs).items()}) # noqa: F821
       del inputs, tinygrad_model, tinygrad_jitted_model
-  except Exception as e:
-    # model crashed
-    print(f"{m} crashed on {device} with: {e}")
-    return
+    except CompileError as e:
+      # METAL fails with buffer count limit
+      if m == "dm" and device == "METAL": return
+      raise e
 
   # convert model to torch
   try: