[問答] 關於 gigabit 網路卡

看板Network作者gn00618777 (非常念舊)時間8年前 (2015/11/05 16:00)推噓2(2推 0噓 3→)

留言5則, 3人參與討論串1/2 (看更多)

事情是這樣的我這邊有一個 freescale 的開發板。要用 iperf 指令來測試他的 throughput 板子和筆電之間對連，兩邊都有安裝 iperf。我筆電當 server: iperf.exe -s -w 256K -i 1 -M 64 板子當 client: iperf -c 10.10.10.1 -i 1 -w 256K -M 64 MTU 為 64 結果: 效能接近官方文件的 400Mbps [ 3] 0.0- 1.0 sec 41.8 MBytes 350 Mbits/sec [ 3] 1.0- 2.0 sec 38.5 MBytes 323 Mbits/sec [ 3] 2.0- 3.0 sec 42.4 MBytes 355 Mbits/sec [ 3] 3.0- 4.0 sec 49.0 MBytes 411 Mbits/sec [ 3] 4.0- 5.0 sec 49.4 MBytes 414 Mbits/sec [ 3] 5.0- 6.0 sec 50.2 MBytes 422 Mbits/sec [ 3] 6.0- 7.0 sec 50.4 MBytes 423 Mbits/sec [ 3] 7.0- 8.0 sec 44.1 MBytes 370 Mbits/sec [ 3] 8.0- 9.0 sec 44.5 MBytes 373 Mbits/sec [ 3] 9.0-10.0 sec 47.1 MBytes 395 Mbits/sec [ 3] 0.0-10.0 sec 458 MBytes 384 Mbits/sec =========================================================================== 如果我改為 iperf.exe -s -w 256K -i 1 -M 128 (筆電) iperf -c 10.10.10.1 -i 1 -w 256K -M 128 (板子) 效能其差無比: [ 3] 0.0- 1.0 sec 5.88 MBytes 49.3 Mbits/sec [ 3] 1.0- 2.0 sec 6.38 MBytes 53.5 Mbits/sec [ 3] 2.0- 3.0 sec 6.25 MBytes 52.4 Mbits/sec [ 3] 3.0- 4.0 sec 6.38 MBytes 53.5 Mbits/sec [ 3] 4.0- 5.0 sec 6.25 MBytes 52.4 Mbits/sec [ 3] 5.0- 6.0 sec 6.25 MBytes 52.4 Mbits/sec [ 3] 6.0- 7.0 sec 6.38 MBytes 53.5 Mbits/sec [ 3] 7.0- 8.0 sec 6.25 MBytes 52.4 Mbits/sec [ 3] 8.0- 9.0 sec 6.25 MBytes 52.4 Mbits/sec [ 3] 9.0-10.0 sec 6.25 MBytes 52.4 Mbits/sec [ 3] 0.0-10.0 sec 62.6 MBytes 52.5 Mbits/sec ============================================================================= 如果我將 MTU 改成 -M 256 512 1024 1280 1518 ，會慢慢趨近於400，且從 -M 128 開始，throughput 大約是兩倍增加，也就是上面的數值x2，這樣似乎 MTU 成了關鍵，有沒有高手能夠為我解惑這種行為? 我單獨用筆電做測試 ping wwww.google.com -f -l xxxx 去算他的 MTU，發現用 128 也是會卡卡的，最後xxxx數值為 1468 才比較順，總而言之上面筆電和板子對連結果，我不知道為何從 -M 64 變成 -128 效能會差那麼多..... 懇請指教，謝謝。 -- ※ 發信站: 批踢踢實業坊(ptt.cc), 來自: 111.251.101.116 ※ 文章網址: https://www.ptt.cc/bbs/Network/M.1446710425.A.3DB.html

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