Piecewise Cuda Graph Docs (#19738)

Signed-off-by: yuweia <ayw.sirius19@gmail.com>
Co-authored-by: Wenyao Gao <wgao11@u.rochester.edu>

docs/advanced_features/server_arguments.md

@@ -436,7 +436,8 @@ Please consult the documentation below and [server_args.py](https://github.com/s
 | `--tbo-token-distribution-threshold` | The threshold of token distribution between two batches in micro-batch-overlap, determines whether to two-batch-overlap or two-chunk-overlap. Set to 0 denote disable two-chunk-overlap. | `0.48` | Type: float |
 | `--enable-torch-compile` | Optimize the model with torch.compile. Experimental feature. | `False` | bool flag (set to enable) |
 | `--enable-torch-compile-debug-mode` | Enable debug mode for torch compile. | `False` | bool flag (set to enable) |
-| `--enable-piecewise-cuda-graph` | Optimize the model with piecewise cuda graph for extend/prefill only. Experimental feature. | `False` | bool flag (set to enable) |
+| `--disable-piecewise-cuda-graph` | Disable piecewise cuda graph for extend/prefill. PCG is enabled by default. | `False` | bool flag (set to disable) |
+| `--enforce-piecewise-cuda-graph` | Enforce piecewise cuda graph, skipping all auto-disable conditions. For testing only. | `False` | bool flag (set to enable) |
 | `--piecewise-cuda-graph-tokens` | Set the list of tokens when using piecewise cuda graph. | `None` | Type: JSON list |
 | `--piecewise-cuda-graph-compiler` | Set the compiler for piecewise cuda graph. Choices are: eager, inductor. | `eager` | `eager`, `inductor` |
 | `--torch-compile-max-bs` | Set the maximum batch size when using torch compile. | `32` | Type: int |