<div dir="ltr">Hi,<div><br></div><div>I have a <b>BroadCom NetXtreme II BCM57810 10 Gigabit </b>with a <b>bnx2x</b> driver. I was trying to measure the performance of the network card. I'm running DPDK-L2FWD application to receive and send packets with MAX_PKT_BURST = 1. </div><div>but I noticed that packets are being accumulated somewhere in bnx2x_rxtx. There is some sort of batching/buffering happening in rxtx. So, the latency of the packets is increasing as they have to wait.</div><div>The first packet of the batch is received with the minimum latency and incoming packets are received with the accumulated latency of the previous packets. After a specific number of packets (6-7 packets), the same pattern repeats i.e. a packet arrives with the minimum latency and incoming packets with accumulated latency until the specific number of packets arrives. I've copied the latency measured for some contiguous packets.</div><div><br></div><div>I tried to explore bnx2x_recv_pkts() and bnx2x_xmit_pkts() in bnx2x_rxtx.c, but didn't get any clue why the packets were being accumulated. </div><div><br></div><div> <table cellspacing="0" border="0" style="font-family:"Liberation Sans";font-size:x-small"> <colgroup span="2" width="85"></colgroup> <tbody><tr> <td height="17" align="center" style="font-family:"Liberation Sans"">Sequence</td> <td align="center" style="font-family:"Liberation Sans""> Latency (microseconds)</td> </tr> <tr> <td height="17" align="center" style="font-family:"Liberation Sans"">4825105</td> <td align="center" style="font-family:"Liberation Sans"">9.37207</td> </tr> <tr> <td height="17" align="center" style="font-family:"Liberation Sans"">4825106</td> <td align="center" style="font-family:"Liberation Sans"">10.72168</td> </tr> <tr> <td height="17" align="center" style="font-family:"Liberation Sans"">4825107</td> <td align="center" style="font-family:"Liberation Sans"">15.06543</td> </tr> <tr> <td height="17" align="center" style="font-family:"Liberation Sans"">4825108</td> <td align="center" style="font-family:"Liberation Sans"">19.394043</td> </tr> <tr> <td height="17" align="center" style="font-family:"Liberation Sans"">4825109</td> <td align="center" style="font-family:"Liberation Sans"">22.665039</td> </tr> <tr> <td height="17" align="center" style="font-family:"Liberation Sans"">4825110</td> <td align="center" style="font-family:"Liberation Sans"">26.979004</td> </tr> <tr> <td height="17" align="center" style="font-family:"Liberation Sans"">4825111</td> <td align="center" style="font-family:"Liberation Sans"">8.74707</td> </tr> <tr> <td height="17" align="center" style="font-family:"Liberation Sans"">4825112</td> <td align="center" style="font-family:"Liberation Sans"">11.145996</td> </tr> <tr> <td height="17" align="center" style="font-family:"Liberation Sans"">4825113</td> <td align="center" style="font-family:"Liberation Sans"">14.439941</td> </tr> <tr> <td height="17" align="center" style="font-family:"Liberation Sans"">4825114</td> <td align="center" style="font-family:"Liberation Sans"">18.701172</td> </tr> <tr> <td height="17" align="center" style="font-family:"Liberation Sans"">4825115</td> <td align="center" style="font-family:"Liberation Sans"">23.082031</td> </tr> <tr> <td height="17" align="center" style="font-family:"Liberation Sans"">4825116</td> <td align="center" style="font-family:"Liberation Sans"">27.402832</td> </tr> <tr> <td height="17" align="center" style="font-family:"Liberation Sans"">4825117</td> <td align="center" style="font-family:"Liberation Sans"">9.164062</td> </tr> <tr> <td height="17" align="center" style="font-family:"Liberation Sans"">4825118</td> <td align="center" style="font-family:"Liberation Sans"">11.623047</td> </tr> <tr> <td height="17" align="center" style="font-family:"Liberation Sans"">4825119</td> <td align="center" style="font-family:"Liberation Sans"">15.944824</td> </tr> <tr> <td height="17" align="center" style="font-family:"Liberation Sans"">4825120</td> <td align="center" style="font-family:"Liberation Sans"">19.066406</td> </tr> <tr> <td height="17" align="center" style="font-family:"Liberation Sans"">4825121</td> <td align="center" style="font-family:"Liberation Sans"">23.589355</td> </tr> <tr> <td height="17" align="center" style="font-family:"Liberation Sans"">4825122</td> <td align="center" style="font-family:"Liberation Sans"">27.909668</td> </tr> <tr> <td height="17" align="center" style="font-family:"Liberation Sans"">4825123</td> <td align="center" style="font-family:"Liberation Sans"">9.701172</td> </tr> <tr> <td height="17" align="center" style="font-family:"Liberation Sans"">4825124</td> <td align="center" style="font-family:"Liberation Sans"">11.13916</td> </tr> <tr> <td height="17" align="center" style="font-family:"Liberation Sans"">4825125</td> <td align="center" style="font-family:"Liberation Sans"">15.489746</td> </tr> <tr> <td height="17" align="center" style="font-family:"Liberation Sans"">4825126</td> <td align="center" style="font-family:"Liberation Sans"">19.780762</td> </tr> <tr> <td height="17" align="center" style="font-family:"Liberation Sans"">4825127</td> <td align="center" style="font-family:"Liberation Sans"">23.111816</td> </tr> <tr> <td height="17" align="center" style="font-family:"Liberation Sans"">4825128</td> <td align="center" style="font-family:"Liberation Sans"">27.403809</td> </tr> </tbody></table><br></div></div>