qperf一種測試兩個節點之間的帶寬和延遲的一款工具。它可以工作在TCP/IP或者是RDMA之上。通常，一臺作爲服務器端只要開啓qperf就可以，另一臺作爲客戶端，在客戶端進行帶寬、延遲、CPU利用率等信息的測試。
通過命令我們可以看到除了tcp、udp外，還可以測試rdma, udp, sctp等網絡協議的帶寬和延遲
# qperf --help tests Miscellaneous conf Show configuration quit Cause the server to quit Socket Based rds_bw RDS streaming one way bandwidth rds_lat RDS one way latency sctp_bw SCTP streaming one way bandwidth sctp_lat SCTP one way latency sdp_bw SDP streaming one way bandwidth sdp_lat SDP one way latency tcp_bw TCP streaming one way bandwidth tcp_lat TCP one way latency udp_bw UDP streaming one way bandwidth udp_lat UDP one way latency RDMA Send/Receive rc_bi_bw RC streaming two way bandwidth rc_bw RC streaming one way bandwidth rc_lat RC one way latency uc_bi_bw UC streaming two way bandwidth uc_bw UC streaming one way bandwidth uc_lat UC one way latency ud_bi_bw UD streaming two way bandwidth ud_bw UD streaming one way bandwidth ud_lat UD one way latency xrc_bi_bw XRC streaming two way bandwidth xrc_bw XRC streaming one way bandwidth xrc_lat XRC one way latency RDMA rc_rdma_read_bw RC RDMA read streaming one way bandwidth rc_rdma_read_lat RC RDMA read one way latency rc_rdma_write_bw RC RDMA write streaming one way bandwidth rc_rdma_write_lat RC RDMA write one way latency rc_rdma_write_poll_lat RC RDMA write one way polling latency uc_rdma_write_bw UC RDMA write streaming one way bandwidth uc_rdma_write_lat UC RDMA write one way latency uc_rdma_write_poll_lat UC RDMA write one way polling latency InfiniBand Atomics rc_compare_swap_mr RC compare and swap messaging rate rc_fetch_add_mr RC fetch and add messaging rate Verification ver_rc_compare_swap Verify RC compare and swap ver_rc_fetch_add Verify RC fetch and add
接下來我們看一下qperf提供的一些例子，myserver就只作爲服務器端節點的IP
# qperf --help examples In these examples, we first run qperf on a node called myserver in server mode by invoking it with no arguments. In all the subsequent examples, we run qperf on another node and connect to the server which we assume has a hostname of myserver. * To run a TCP bandwidth and latency test: qperf myserver tcp_bw tcp_lat * To run a SDP bandwidth test for 10 seconds: qperf myserver -t 10 sdp_bw * To run a UDP latency test and then cause the server to terminate: qperf myserver udp_lat quit * To measure the RDMA UD latency and bandwidth: qperf myserver ud_lat ud_bw * To measure RDMA UC bi-directional bandwidth: qperf myserver rc_bi_bw * To get a range of TCP latencies with a message size from 1 to 64K qperf myserver -oo msg_size:1:64K:*2 -vu tcp_lat
通過上面的例子我們要熟悉一些參數：
-t 這個參數指定測試維持的時間長度
-oo 通過man查看它的用法是"-oo Var:Init:Last:Incr" Var就是參數，Init就是初始值，Last就只最大值，Incr就是增長數，*2意思是兩倍增長，2則是每次加上2字節。