Bandwidth
為什麼頻寬不是~10G？
我最初發佈在“網路工程”上，但我被告知在這裡問。
我有 2 台伺服器直接通過 10G 電纜連接。我需要知道連接是否良好，並且確實具有 10G 吞吐量。如果不是，我該如何檢查問題所在？我使用 IPERF 檢查頻寬。
更新 我配置了巨型數據包、極端中斷率、接收/發送緩衝區的最大值。對於 IPERF，我只對伺服器使用“iperf3.exe -s”，對客戶端使用“iperf3.exe -c IP”。
根據測試，頻寬為 1.5-1.7 Gbits/sec。這是否意味著連接是10G？可能是什麼問題呢？
伺服器 A 是 Windows 8.1 Pro 64bit
伺服器 B 是 Windows 7 Enterprise 64bit
這是 ServerA (192.168.10.100) 是伺服器且 ServerB (192.168.10.200) 是客戶端時的輸出：
----------------------------------------------------------- Server listening on 5201 ----------------------------------------------------------- Accepted connection from 192.168.10.200, port 63772 [ 5] local 192.168.10.100 port 5201 connected to 192.168.10.200 port 63773 [ ID] Interval Transfer Bandwidth [ 5] 0.00-1.00 sec 170 MBytes 1.42 Gbits/sec [ 5] 1.00-2.00 sec 217 MBytes 1.82 Gbits/sec [ 5] 2.00-3.00 sec 217 MBytes 1.82 Gbits/sec [ 5] 3.00-4.00 sec 214 MBytes 1.80 Gbits/sec [ 5] 4.00-5.00 sec 217 MBytes 1.82 Gbits/sec [ 5] 5.00-6.00 sec 207 MBytes 1.74 Gbits/sec [ 5] 6.00-7.00 sec 199 MBytes 1.67 Gbits/sec [ 5] 7.00-8.00 sec 206 MBytes 1.73 Gbits/sec [ 5] 8.00-9.00 sec 192 MBytes 1.61 Gbits/sec [ 5] 9.00-10.00 sec 209 MBytes 1.75 Gbits/sec [ 5] 10.00-10.16 sec 30.3 MBytes 1.63 Gbits/sec - - - - - - - - - - - - - - - - - - - - - - - - - [ ID] Interval Transfer Bandwidth [ 5] 0.00-10.16 sec 0.00 Bytes 0.00 bits/sec sender [ 5] 0.00-10.16 sec 2.03 GBytes 1.72 Gbits/sec receiver這是當 B (192.168.10.200) 是伺服器並且 A (192.168.10.100) 是客戶端時的輸出：
----------------------------------------------------------- Server listening on 5201 ----------------------------------------------------------- Accepted connection from 192.168.10.100, port 55565 [ 5] local 192.168.10.200 port 5201 connected to 192.168.10.100 port 55566 [ ID] Interval Transfer Bandwidth [ 5] 0.00-1.00 sec 170 MBytes 1.43 Gbits/sec [ 5] 1.00-2.00 sec 175 MBytes 1.47 Gbits/sec [ 5] 2.00-3.00 sec 175 MBytes 1.47 Gbits/sec [ 5] 3.00-4.00 sec 179 MBytes 1.50 Gbits/sec [ 5] 4.00-5.00 sec 181 MBytes 1.52 Gbits/sec [ 5] 5.00-6.00 sec 200 MBytes 1.68 Gbits/sec [ 5] 6.00-7.00 sec 176 MBytes 1.47 Gbits/sec [ 5] 7.00-8.00 sec 177 MBytes 1.48 Gbits/sec [ 5] 8.00-9.00 sec 186 MBytes 1.56 Gbits/sec [ 5] 9.00-10.00 sec 179 MBytes 1.50 Gbits/sec [ 5] 10.00-10.04 sec 6.42 MBytes 1.46 Gbits/sec - - - - - - - - - - - - - - - - - - - - - - - - - [ ID] Interval Transfer Bandwidth [ 5] 0.00-10.04 sec 0.00 Bytes 0.00 bits/sec sender [ 5] 0.00-10.04 sec 1.76 GBytes 1.51 Gbits/sec receiver更新2-UDP
當 192.168.10.100 為伺服器時
iperf3.exe -c 192.168.10.100 -u -V iperf 3.1.3 CYGWIN_NT-6.1 ServerB 2.5.1(0.297/5/3) 2016-04-21 22:14 x86_64 Time: Tue, 09 Aug 2016 19:58:03 GMT Connecting to host 192.168.10.100, port 5201 Cookie: ServerB.1470772683.561800.7c902a3e559 [ 4] local 192.168.10.200 port 63675 connected to 192.168.10.100 port 5201 Starting Test: protocol: UDP, 1 streams, 8192 byte blocks, omitting 0 seconds, 1 0 second test [ ID] Interval Transfer Bandwidth Total Datagrams [ 4] 0.00-1.00 sec 128 KBytes 1.05 Mbits/sec 16 [ 4] 1.00-2.00 sec 128 KBytes 1.05 Mbits/sec 16 [ 4] 2.00-3.00 sec 128 KBytes 1.05 Mbits/sec 16 [ 4] 3.00-4.00 sec 128 KBytes 1.05 Mbits/sec 16 [ 4] 4.00-5.00 sec 128 KBytes 1.05 Mbits/sec 16 [ 4] 5.00-6.00 sec 128 KBytes 1.05 Mbits/sec 16 [ 4] 6.00-7.00 sec 128 KBytes 1.05 Mbits/sec 16 [ 4] 7.00-8.00 sec 128 KBytes 1.05 Mbits/sec 16 [ 4] 8.00-9.00 sec 128 KBytes 1.05 Mbits/sec 16 [ 4] 9.00-10.00 sec 128 KBytes 1.05 Mbits/sec 16 - - - - - - - - - - - - - - - - - - - - - - - - - Test Complete. Summary Results: [ ID] Interval Transfer Bandwidth Jitter Lost/Total Datag rams [ 4] 0.00-10.00 sec 1.25 MBytes 1.05 Mbits/sec 0.437 ms 0/160 (0%) [ 4] Sent 160 datagrams CPU Utilization: local/sender 1.7% (0.9%u/0.8%s), remote/receiver 0.1% (0.0%u/0. 1%s)當 192.168.10.200 為伺服器時
iperf3.exe -c 192.168.10.200 -u -V iperf 3.1.3 CYGWIN_NT-6.3 ServerA 2.5.1(0.297/5/3) 2016-04-21 22:14 x86_64 Time: Tue, 09 Aug 2016 20:37:11 GMT Connecting to host 192.168.10.200, port 5201 Cookie: ServerA.1470775031.986727.6f8e913650af9b [ 4] local 192.168.10.100 port 51834 connected to 192.168.10.200 port 5201 Starting Test: protocol: UDP, 1 streams, 8192 byte blocks, omitting 0 seconds, 1 0 second test [ ID] Interval Transfer Bandwidth Total Datagrams [ 4] 0.00-1.00 sec 152 KBytes 1.24 Mbits/sec 19 [ 4] 1.00-2.00 sec 144 KBytes 1.18 Mbits/sec 18 [ 4] 2.00-3.00 sec 160 KBytes 1.31 Mbits/sec 20 [ 4] 3.00-4.00 sec 160 KBytes 1.31 Mbits/sec 20 [ 4] 4.00-5.00 sec 152 KBytes 1.25 Mbits/sec 19 [ 4] 5.00-6.00 sec 152 KBytes 1.24 Mbits/sec 19 [ 4] 6.00-7.00 sec 152 KBytes 1.25 Mbits/sec 19 [ 4] 7.00-8.00 sec 152 KBytes 1.25 Mbits/sec 19 [ 4] 8.00-9.00 sec 152 KBytes 1.24 Mbits/sec 19 [ 4] 9.00-10.00 sec 144 KBytes 1.18 Mbits/sec 18 - - - - - - - - - - - - - - - - - - - - - - - - - Test Complete. Summary Results: [ ID] Interval Transfer Bandwidth Jitter Lost/Total Datag rams [ 4] 0.00-10.00 sec 1.48 MBytes 1.25 Mbits/sec 0.202 ms 0/189 (0%) [ 4] Sent 189 datagrams CPU Utilization: local/sender 0.1% (0.1%u/0.0%s), remote/receiver 0.0% (0.0%u/0. 0%s)UPDATE3 - NTTTCP W/O -NDL
服務
ntttcp.exe -s -m 8,*,192.168.10.200 -l 128k -a 2 -t 15 Copyright Version 5.31 Network activity progressing... Thread Time(s) Throughput(KB/s) Avg B / Compl ====== ======= ================ ============= 0 15.000 65544.533 131072.000 1 15.000 65518.933 131072.000 2 15.000 93585.067 131072.000 3 15.002 63906.146 131072.000 4 15.000 65536.000 131072.000 5 15.000 62310.400 131072.000 6 15.001 81837.744 131072.000 7 15.001 73262.316 131072.000 ##### Totals: ##### Bytes(MEG) realtime(s) Avg Frame Size Throughput(MB/s) ================ =========== ============== ================ 8371.875000 15.001 8854.867 558.088 Throughput(Buffers/s) Cycles/Byte Buffers ===================== =========== ============= 4464.702 17.198 66975.000 DPCs(count/s) Pkts(num/DPC) Intr(count/s) Pkts(num/intr) ============= ============= =============== ============== 12120.992 0.823 30450.170 0.328 Packets Sent Packets Received Retransmits Errors Avg. CPU % ============ ================ =========== ====== ========== 991381 149616 9 0 36.026伺服器B
ntttcp.exe -r -m 8,*,192.168.10.200 -rb 2M -a 16 -t 15 Copyright Version 5.31 Network activity progressing... Thread Time(s) Throughput(KB/s) Avg B / Compl ====== ======= ================ ============= 0 15.000 65546.450 60268.990 1 14.999 65523.318 60229.282 2 14.999 93582.889 60659.943 3 14.999 63900.843 61621.870 4 15.000 65536.817 60278.174 5 14.999 62316.071 61141.628 6 14.999 81840.156 60394.032 7 14.999 73264.934 60858.538 ##### Totals: ##### Bytes(MEG) realtime(s) Avg Frame Size Throughput(MB/s) ================ =========== ============== ================ 8371.320061 14.999 8942.835 558.125 Throughput(Buffers/s) Cycles/Byte Buffers ===================== =========== ============= 8930.003 5.314 133941.121 DPCs(count/s) Pkts(num/DPC) Intr(count/s) Pkts(num/intr) ============= ============= =============== ============== 7965.264 8.216 14260.151 4.589 Packets Sent Packets Received Retransmits Errors Avg. CPU % ============ ================ =========== ====== ========== 146841 981564 1 0 9.699UPDATE4 - NTTTCP 與 -NDL
服務
ntttcp.exe -s -m 8,*,192.168.10.200 -l 128k -a 2 -t 15 -ndl Copyright Version 5.31 Network activity progressing... Thread Time(s) Throughput(KB/s) Avg B / Compl ====== ======= ================ ============= 0 14.999 78059.604 131072.000 1 15.000 76902.400 131072.000 2 14.999 59882.392 131072.000 3 14.999 62485.232 131072.000 4 14.999 72734.449 131072.000 5 15.001 77520.165 131072.000 6 15.000 62702.933 131072.000 7 15.000 62771.200 131072.000 ##### Totals: ##### Bytes(MEG) realtime(s) Avg Frame Size Throughput(MB/s) ================ =========== ============== ================ 8101.250000 15.000 8912.094 540.083 Throughput(Buffers/s) Cycles/Byte Buffers ===================== =========== ============= 4320.667 17.355 64810.000 DPCs(count/s) Pkts(num/DPC) Intr(count/s) Pkts(num/intr) ============= ============= =============== ============== 9966.333 0.974 29515.333 0.329 Packets Sent Packets Received Retransmits Errors Avg. CPU % ============ ================ =========== ====== ========== 953174 145579 1 0 35.182伺服器B
ntttcp.exe -r -m 8,*,192.168.10.200 -rb 2M -a 16 -t 15 -ndl Copyright Version 5.31 Network activity progressing... Thread Time(s) Throughput(KB/s) Avg B / Compl ====== ======= ================ ============= 0 15.000 78054.000 60255.789 1 15.001 76903.606 60839.375 2 15.000 59880.183 61786.888 3 14.999 62483.832 60812.856 4 15.000 72730.333 61516.405 5 14.999 77520.335 60398.365 6 14.998 62701.660 60628.917 7 14.998 62771.436 60585.766 ##### Totals: ##### Bytes(MEG) realtime(s) Avg Frame Size Throughput(MB/s) ================ =========== ============== ================ 8100.944093 14.999 8943.556 540.099 Throughput(Buffers/s) Cycles/Byte Buffers ===================== =========== ============= 8641.583 4.888 129615.105 DPCs(count/s) Pkts(num/DPC) Intr(count/s) Pkts(num/intr) ============= ============= =============== ============== 7912.594 8.003 14043.670 4.509 Packets Sent Packets Received Retransmits Errors Avg. CPU % ============ ================ =========== ====== ========== 143914 949785 0 0 8.633
事實證明，問題與 Windows 7/8 客戶端如何管理 TCP 視窗縮放有關。
預設情況下，Windows 客戶端版本更喜歡相對較小的 TCP 視窗，優先考慮延遲與吞吐量。當使用非常快的連結時，例如在這種情況下，將自動調整設置為正常可以帶來顯著的頻寬增益。
要將自動調整設置為更明智的值，您可以使用命令
netsh interface tcp set heuristics disabled。無論如何，請在這裡查看更多資訊。