fix: reduce VLLM_MOE_DP_CHUNK_SIZE to 384 (#5307)

Signed-off-by: Piotr Tarasiewicz <ptarasiewicz@nvidia.com>

recipes/deepseek-r1/vllm/disagg/README.md

@@ -92,5 +92,6 @@ curl -sS http://localhost:8000/v1/chat/completions \
 - If your cluster/network requires specific interfaces, adjust environment variables (e.g., `NCCL_SOCKET_IFNAME`) in the manifest accordingly.
 - If your storage class differs, update `storageClassName` before applying the PVC.
 - **If you want to run multinode deployments, IBGDA (InfiniBand GPU Direct Async) must be enabled on your nodes.** To enable IBGDA, you can follow this configuration script: [configure_system_drivers.sh](https://github.com/vllm-project/vllm/blob/v0.11.2/tools/ep_kernels/configure_system_drivers.sh). The script configures NVIDIA driver parameters and requires a system reboot to take effect.
+- `VLLM_MOE_DP_CHUNK_SIZE` can be tuned further. The value 384 was chosen to be largest possible that still can be deployed on 16 H200s. This value should be greater than per rank concurrency.
 
 

recipes/deepseek-r1/vllm/disagg/deploy_hopper_16gpu.yaml

@@ -58,7 +58,7 @@ spec:
             - name: VLLM_ALL2ALL_BACKEND
               value: deepep_low_latency
             - name: VLLM_MOE_DP_CHUNK_SIZE
-              value: "512"
+              value: "384"
             - name: VLLM_SKIP_P2P_CHECK
               value: "1"
             - name: VLLM_RANDOMIZE_DP_DUMMY_INPUTS
@@ -67,8 +67,6 @@ spec:
               value: enabled
             - name: VLLM_MOE_ROUTING_SIMULATION_STRATEGY
               value: "uniform_random"
-            - name: NVSHMEM_QP_DEPTH
-              value: "1512"
             - name: GLOO_SOCKET_IFNAME
               value: eth0
           command:
@@ -125,7 +123,7 @@ spec:
             - name: VLLM_ALL2ALL_BACKEND
               value: deepep_high_throughput
             - name: VLLM_MOE_DP_CHUNK_SIZE
-              value: "512"
+              value: "384"
             - name: VLLM_SKIP_P2P_CHECK
               value: "1"
             - name: VLLM_RANDOMIZE_DP_DUMMY_INPUTS
@@ -134,8 +132,6 @@ spec:
               value: enabled
             - name: VLLM_MOE_ROUTING_SIMULATION_STRATEGY
               value: "uniform_random"
-            - name: NVSHMEM_QP_DEPTH
-              value: "1512"
             - name: GLOO_SOCKET_IFNAME
               value: eth0
           command: