title: what is the source of packet loss using pfsend
body: <p>I'm using pfsend to send traffic at very high speed from a host1 to a host2. </p>
  
  <p>At host2 side, I'm using pfcount to get some statistics regarding packet dropped and number of packets received.</p>
  
  <pre><code>Some details: 
  
  The NICs used are Mellanox Connectx-3. 
  
  pf_ring module is loaded at host2 side
  </code></pre>
  
  <p>I'm running pfsend from host1 like this : <code>pfsend -z -n 0 -i eth2 -m MAC@</code></p>
  
  <p>The output result of <code>pfsend</code> is as follows :</p>
  
  <pre><code>Sending packets on eth2
  Using PF_RING v.6.1.1
  Dumping statistics on /proc/net/pf_ring/stats/10047-eth2.143
  TX rate: [current 1'263'756.00 pps/0.85 Gbps][average 1'263'756.00 pps/0.85 Gbps][total 1'263'756.00 pkts]
  TX rate: [current 1'248'427.54 pps/0.84 Gbps][average 1'256'091.65 pps/0.84 Gbps][total 2'512'221.00 pkts]
  TX rate: [current 1'264'407.18 pps/0.85 Gbps][average 1'258'863.51 pps/0.85 Gbps][total 3'776'656.00 pkts]
  TX rate: [current 1'241'021.73 pps/0.83 Gbps][average 1'254'403.03 pps/0.84 Gbps][total 5'017'710.00 pkts]
  </code></pre>
  
  <p>At host2 side, the output of pfcount is as follows :</p>
  
  <pre><code>=========================
  Absolute Stats: [2605633 pkts rcvd][687723 pkts dropped]
  Total Pkts=3293356/Dropped=20.9 %
  2'605'633 pkts - 218'874'205 bytes [1'301'036.68 pkt/sec - 874.30 Mbit/sec]
  =========================
  Actual Stats: 870113 pkts [1'000.10 ms][870'019.03 pps/0.58 Gbps]
  =========================
  
  =========================
  Absolute Stats: [3480356 pkts rcvd][910603 pkts dropped]
  Total Pkts=4390959/Dropped=20.7 %
  3'480'356 pkts - 292'351'364 bytes [1'158'905.29 pkt/sec - 778.79 Mbit/sec]
  =========================
  Actual Stats: 874723 pkts [1'000.40 ms][874'368.88 pps/0.59 Gbps]
  =========================
  
  =========================
  Absolute Stats: [4354304 pkts rcvd][1134899 pkts dropped]
  Total Pkts=5489203/Dropped=20.7 %
  4'354'304 pkts - 365'763'428 bytes [1'087'622.15 pkt/sec - 730.89 Mbit/sec]
  =========================
  Actual Stats: 873948 pkts [1'000.36 ms][873'627.37 pps/0.59 Gbps]
  =========================
  
  =========================
  Absolute Stats: [4930161 pkts rcvd][1287203 pkts dropped]
  Total Pkts=6217364/Dropped=20.7 %
  4'930'161 pkts - 414'135'907 bytes [985'321.78 pkt/sec - 662.14 Mbit/sec]
  =========================
  Actual Stats: 575857 pkts [1'000.09 ms][575'801.14 pps/0.39 Gbps]
  =========================
  </code></pre>
  
  <p>Any one might provide me with some insights ? Is it related to the switch that connects the two hosts ? or something related to Linux Networking Kernel ?
  Regards.</p>