[Bugfix] Add init_workspace_manager to moe kernel benchmarks (#31042)

Signed-off-by: mgoin <mgoin64@gmail.com>

benchmarks/kernels/benchmark_grouped_gemm_cutlass.py

@@ -14,6 +14,7 @@ from vllm.model_executor.layers.fused_moe.fused_moe import (
     fused_topk,
 )
 from vllm.utils.argparse_utils import FlexibleArgumentParser
+from vllm.v1.worker.workspace import init_workspace_manager
 
 DEFAULT_MODELS = [
     "mistralai/Mixtral-8x7B-Instruct-v0.1",
@@ -364,6 +365,10 @@ def bench_run(
 
 
 def main(args):
+    # Initialize workspace manager (required for CUTLASS MoE kernels)
+    device = torch.device("cuda:0")
+    init_workspace_manager(device)
+
     print("Benchmarking models:")
     for i, model in enumerate(args.models):
         print(f"[{i}]  {model}")