Date: Fri, 23 Sep 2016 19:59:09 +0200 From: Ben RUBSON <ben.rubson@gmail.com> To: FreeBSD Net <freebsd-net@freebsd.org> Subject: netstat counts input traffic twice Message-ID: <94953762-4397-476D-AD61-A39914F27938@gmail.com>
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Hello, I found a strange issue where input traffic is counted twice, sometimes more. How to reproduce : dst# netstat -b -I mlxen1 Name Mtu Network Ipkts Ibytes Opkts Obytes mlxen 9000 <Link#3> 223135371 2297323715986 242534891 1594979072449 mlxen - 192.168.0.0/1 140330886 1143518393245 239792545 1583789250111 dst# sysctl hw.mlxen1.stat.rx_bytes hw.mlxen1.stat.rx_bytes: 1151840666259 dst# iperf -s src# iperf -c dst -i 1 -t 10 -n 1G [ ID] Interval Transfer Bandwidth [ 3] 0.0- 0.3 sec 1.00 GBytes 33.0 Gbits/sec dst# netstat -b -I mlxen1 Name Mtu Network Ipkts Ibytes Opkts Obytes mlxen 9000 <Link#3> 223257341 2299482904332 242578378 1594982116541 mlxen - 192.168.0.0/1 140378866 1144594630061 239836031 1583791511391 dst# sysctl hw.mlxen1.stat.rx_bytes hw.mlxen1.stat.rx_bytes: 1152922946009 Results : iperf on dst gives good results : dst# iperf -s [ ID] Interval Transfer Bandwidth [ 3] 0.0- 0.3 sec 1.00 GBytes 33.0 Gbits/sec hw.mlxen1.stat.rx_bytes also gives good results : 1152922946009 - 1151840666259 = 1GG However, netstat : 2299482904332 - 2297323715986 = 2GB (!) 1144594630061 - 1143518393245 = 1GB Strangely enough input packets are counted twice for the "link" interface. Why ? Is there a bug somewhere ? Of course looking at the real time results with netstat -w 1 gives the same uncorrect results. As well as with systat -ifstat. iftop (which I do not like so much because it sometimes hangs the traffic) seems to give good results however. I tested this on 3 similar servers, in all possible ways. Every time I get these strange results. This behaviour of course totally brakes reporting tools based on netstat. My 2 systems : # uname -r 11.0-RC3 # uptime 7:40p.m. up 47 mins, 1 users, load averages: 0.00, 0.00, 0.00 # mst status MST devices: ------------ pci0:133:0:0 - MT27500 Family [ConnectX-3] # flint -d pci0:133:0:0 q Image type: FS2 FW Version: 2.36.5000 FW Release Date: 26.1.2016 Product Version: 02.36.50.00 Rom Info: type=PXE version=3.4.718 devid=4099 Device ID: 4099 PSID: MT_1090110023 Thank you very much ! Ben
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