Add more environment variables for NCCL

Author: msimberg

docs/software/communication/nccl.md

@@ -18,11 +18,20 @@ While the container engine sets these automatically when using the NCCL hook, th
 
 ```bash
 export NCCL_NET="AWS Libfabric" # (1)!
+export NCCL_CROSS_NIC="1"
+export NCCL_NET_FORCE_FLUSH="1"
 export NCCL_NET_GDR_LEVEL=PHB # (2)!
 export FI_CXI_DEFAULT_CQ_SIZE=131072 # (3)!
 export FI_CXI_DEFAULT_TX_SIZE=32768
 export FI_CXI_DISABLE_HOST_REGISTER=1
+export FI_CXI_RDZV_EAGER_SIZE="0"
+export FI_CXI_RDZV_GET_MIN="0"
+export FI_CXI_RDZV_THRESHOLD="0"
+export FI_CXI_RX_MATCH_MODE="hardware"
 export FI_CXI_RX_MATCH_MODE=software
+export FI_CXI_SAFE_DEVMEM_COPY_THRESHOLD="16777216"
+export FI_MR_CACHE_MAX_COUNT="524288"
+export FI_MR_CACHE_MAX_SIZE="-1"
 export FI_MR_CACHE_MONITOR=userfaultfd
 export MPICH_GPU_SUPPORT_ENABLED=0 # (4)!
 ```