beam benchmark tests (#7638)

* beam benchmark tests

* lower AMD number somehow

* less flaky

test/external/speed_v_theoretical.py

@@ -0,0 +1,51 @@
+import unittest, time
+from tinygrad import Tensor, TinyJit, Device
+from tinygrad.helpers import Context, DEBUG
+
+class TestKernelSpeed(unittest.TestCase):
+  def _test_matmul(self, M, N=None, K=None, nv=None, amd=None):
+    # (MxK) @ (KxN)
+    @TinyJit
+    def f(a, b): return (a @ b).realize()
+
+    if N is None: N = M
+    if K is None: K = M
+    tms = []
+    with Context(BEAM=3):
+      for _ in range(10):
+        with Context(BEAM=0, DEBUG=0):
+          a = Tensor.rand(M, K, dtype="half").realize()
+          b = Tensor.rand(K, N, dtype="half").realize()
+        Device.default.synchronize()
+        st = time.perf_counter()
+        _c = f(a, b)
+        Device.default.synchronize()
+        tms.append(time.perf_counter() - st)
+
+    ops = 2 * M * N * K
+    tm = min(tms)
+    tflops = ops / tm / 1e12
+
+    if DEBUG >= 1:
+      print(f"{tm=}")
+      print(f"{tflops=}")
+
+    if Device.DEFAULT == "NV":
+      if DEBUG >=1: print(f"target: {nv}")
+      self.assertGreater(tflops, nv)
+    if Device.DEFAULT == "AMD":
+      if DEBUG >=1: print(f'target: {amd}')
+      self.assertGreater(tflops, amd)
+
+  # TODO: smaller ones has other overhead in synchronize
+  # TODO: AMD number can be better (perf level?)
+  def test_gemm_1024(self): self._test_matmul(1024, nv=9, amd=5)
+  def test_gemm_2048(self): self._test_matmul(2048, nv=50, amd=20)
+  def test_gemm_4096(self): self._test_matmul(4096, nv=95, amd=30)
+  def test_gemm_8192(self): self._test_matmul(8192, nv=130, amd=50)
+
+  # TODO: add gemv, which is memory bounded
+
+
+if __name__ == '__main__':
+  unittest.main()