# CUDA Python 11.6.0 Release notes

Released on Januray 12, 2022

## Highlights
- Support CUDA Toolkit 11.6
- Support Profiler APIs
- Support Graphic APIs (EGL, GL, VDPAU)
- Support changing default stream
- Relaxed primitive interoperability

### Default stream

Changing default stream to Per-Thread-Default-Stream (PTDS) is done through environment variable before execution:

```{code-block} shell
export CUDA_PYTHON_CUDA_PER_THREAD_DEFAULT_STREAM=1
```

When set to 1, the default stream is the per-thread default stream. When set to 0, the default stream is the legacy default stream. This defaults to 0, for the legacy default stream. See [Stream Synchronization Behavior](https://docs.nvidia.com/cuda/cuda-runtime-api/stream-sync-behavior.html) for an explanation of the legacy and per-thread default streams.

### Primitive interoperability

APIs accepting classes that wrap a primitive value are now interoperable with the underlining value.

Example 1: Structure member handles interoperability.

```{code-block} python
>>> waitParams = cuda.CUstreamMemOpWaitValueParams_st()
>>> waitParams.value64 = 1
>>> waitParams.value64
<cuuint64_t 1>
>>> waitParams.value64 = cuda.cuuint64_t(2)
>>> waitParams.value64
<cuuint64_t 2>
```

Example 2: Function signature handles interoperability.

```{code-block} python
>>> cudart.cudaStreamQuery(cudart.cudaStreamNonBlocking)
(<cudaError_t.cudaSuccess: 0>,)
>>> cudart.cudaStreamQuery(cudart.cudaStream_t(cudart.cudaStreamNonBlocking))
(<cudaError_t.cudaSuccess: 0>,)
```

## Limitations

### CUDA Functions Not Supported in this Release

- Symbol APIs
    - cudaGraphExecMemcpyNodeSetParamsFromSymbol
    - cudaGraphExecMemcpyNodeSetParamsToSymbol
    - cudaGraphAddMemcpyNodeToSymbol
    - cudaGraphAddMemcpyNodeFromSymbol
    - cudaGraphMemcpyNodeSetParamsToSymbol
    - cudaGraphMemcpyNodeSetParamsFromSymbol
    - cudaMemcpyToSymbol
    - cudaMemcpyFromSymbol
    - cudaMemcpyToSymbolAsync
    - cudaMemcpyFromSymbolAsync
    - cudaGetSymbolAddress
    - cudaGetSymbolSize
    - cudaGetFuncBySymbol
- Launch Options
    - cudaLaunchKernel
    - cudaLaunchCooperativeKernel
    - cudaLaunchCooperativeKernelMultiDevice
- cudaSetValidDevices
- cudaVDPAUSetVDPAUDevice

```{note} Deprecated APIs are removed from tracking
```