Date: Tue, 21 May 2013 12:29:27 +0200 From: Marko Zec <zec@fer.hr> To: <freebsd-net@freebsd.org> Cc: liujie <liujie@263.net> Subject: Re: netmap bridge can tranmit big packet in line rate ? Message-ID: <201305211229.28182.zec@fer.hr> In-Reply-To: <1369128316187-5813643.post@n5.nabble.com> References: <1369036008085-5813346.post@n5.nabble.com> <CA%2BhQ2%2BhURSWVxTcxCW7Jmd6n1y54ZVC3uUJO1uzcmHCeDuJVFA@mail.gmail.com> <1369128316187-5813643.post@n5.nabble.com>
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On Tuesday 21 May 2013 11:25:16 liujie wrote: > Hi, Prof.Luigi RIZZO > > Firstly i should thank you for netmap. I tried to send a e-mail to you > yestoday, but it was rejected. > > I used two machines to test netmap bridge. all with i7-2600 cpu and > intel 82599 dual-interfaces card. > > One worked as sender and receiver with pkt-gen, the other worked as > bridge with bridge.c. > > as you said,I feeled comfous too when i saw the big packet performance > dropped, i tried to change the memory parameters of netmap(netmap_mem1.c > netmap_mem2.c),but it seemed that can not resove the problem. > 60-byte packet send 14882289 pps recv 13994753 pps > 124-byte send 8445770 pps recv 7628942 pps > 252-byte send 4529819 pps recv 3757843 pps > 508-byte send 2350815 pps recv 1645647 pps > 1514-byte send 814288 pps recv 489133 pps > > sender command: pkt-gen -i ix0 -t 500000000 -l 60 > receiver command: pkt-gen -i ix1 -r 500000000 > bridge(other machine) command:bridge -i ix0 -i ix1 > > can sender and receiver on a same machine ? Most likely the PCIe path between the dual-ported card and the CPU is the bottleneck. Depending on the chipset and motherboard design, it may be that your card is only using 4 instead of 8 PCIe lanes, because some of the lanes may be "shared" with another PCIe slot, such as the one in which a graphic card is plugged in. You can also try experimenting with slightly overclocking the PCIe bus if the BIOS permits that - I had no problems overclocking the ixgbe and an AMD PCIe chipset by 25%. Marko
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