Recommended Configuration of UCX Environment Variables

Item	Description	Default Value
UCX_TCP_TX_SEG_SIZE	Size of a buffer in the buffer pool on the TX side.	8KB
UCX_TCP_TX_MAX_BUFS	Maximum number of buffers in the buffer pool on the TX side.	-1
UCX_TCP_TX_BUFS_GROW	Number of buffers that are added every time the buffer pool grows on the TX side.	8
UCX_TCP_RX_SEG_SIZE	Size of a buffer in the buffer pool on the RX side.	64KB
UCX_TCP_RX_MAX_BUFS	Maximum number of buffers in the buffer pool on the RX side.	-1
UCX_TCP_RX_BUFS_GROW	Number of buffers that are added every time the buffer pool grows on the RX side.	8
UCX_TCP_MAX_NUM_EPS	Maximum number of EPs (sockets) that can be created.	256
UCX_TCP_SNDBUF	Size of the TX buffer of the kernel socket.	auto
UCX_TCP_RCVBUF	Size of the RX buffer of the kernel socket.	auto

Item	Description	Default Value
UCX_RC_VERBS_MAX_NUM_EPS	Maximum number of RC EPs that can be created.	256
UCX_RC_VERBS_TX_QUEUE_LEN	Length of the TX queue in a QP.	256
UCX_RC_VERBS_SEG_SIZE	Size of a buffer in the buffer pool.	8256
UCX_RC_VERBS_TX_MAX_BUFS	Maximum number of buffers in the buffer pool on the TX side.	-1
UCX_RC_VERBS_TX_BUFS_GROW	Number of buffers that are added every time the buffer pool grows on the TX side.	1024
UCX_RC_VERBS_TX_CQ_LEN	Maximum length of a CQ in a QP on the TX side, which limits the total number of sent requests.	4096
UCX_RC_VERBS_RX_QUEUE_LEN	Length of the RX queue in a QP.	4095
UCX_RC_VERBS_RX_MAX_BUFS	Maximum number of buffers in the buffer pool on the RX side.	-1
UCX_RC_VERBS_RX_BUFS_GROW	Number of buffers that are added every time the buffer pool grows on the RX side.	0 (automatically selected by UCX)

Item	Description	Default Value
UCX_RC_MLX5_TX_QUEUE_LEN	Length of the TX queue in a QP.	256
UCX_RC_MLX5_SEG_SIZE	Size of a buffer in the buffer pool.	8256
UCX_RC_MLX5_TX_MAX_BUFS	Maximum number of buffers in the buffer pool on the TX side.	-1
UCX_RC_MLX5_TX_BUFS_GROW	Number of buffers that are added every time the buffer pool grows on the TX side.	1024
UCX_RC_MLX5_TX_CQ_LEN	Maximum length of a CQ in a QP on the TX side, which limits the total number of sent requests.	4096
UCX_RC_MLX5_RX_QUEUE_LEN	Length of the RX queue in a QP.	4095
UCX_RC_MLX5_RX_MAX_BUFS	Maximum number of buffers in the buffer pool on the RX side.	-1
UCX_RC_MLX5_RX_BUFS_GROW	Number of buffers that are added every time the buffer pool grows on the RX side.	0 (automatically selected by UCX)

Parent topic: References