calculate overhead based number of gpu devices (#1875)

gpu/gpu_test.go

@@ -18,6 +18,7 @@ func TestBasicGetGPUInfo(t *testing.T) {
 	case "linux", "windows":
 		assert.Greater(t, info.TotalMemory, uint64(0))
 		assert.Greater(t, info.FreeMemory, uint64(0))
+		assert.Greater(t, info.DeviceCount, uint64(0))
 	default:
 		return
 	}
@@ -35,7 +36,6 @@ func TestCPUMemInfo(t *testing.T) {
 	default:
 		return
 	}
-
 }
 
 // TODO - add some logic to figure out card type through other means and actually verify we got back what we expected