From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Wiles, Keith" Subject: Re: Why pktgen-dpdk will receive more packet than sent Date: Tue, 30 Jun 2015 03:15:31 +0000 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable To: "Jiang, Yunhong" , "dev@dpdk.org" Return-path: Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) by dpdk.org (Postfix) with ESMTP id EA747C450 for ; Tue, 30 Jun 2015 05:15:35 +0200 (CEST) Content-Language: en-US Content-ID: List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" On 6/29/15, 9:01 PM, "dev on behalf of Jiang, Yunhong" wrote: >Hi, all > I'm trying to test the l2fwd throughput using >https://github.com/pktgen/Pktgen-DPDK/blob/master/dpdk/examples/pktgen/scr >ipts/rfc2544.lua . However, the pktgen will receive more packets than it >sent out like " Total sent 14786446 recv 14786597, delta 151". I'm really >confused why this will happen. I have the pktgen machine and l2fwd >machine connected to each other directly and bind the igb_uio to the NIC >devices. > >Pktgen> *** Test packet size 64 at rate 100% >Total sent 133856261 recv 131517412, delta -2338849 >*** Test packet size 64 at rate 50% >Total sent 40208555 recv 40207420, delta -1135 >*** Test packet size 64 at rate 25% >PMD: ixgbe_set_rx_function(): Vector rx enabled, please make sure RX >burst size no less than 32. >Total sent 14786446 recv 14786597, delta 151 >*** Test packet size 64 at rate 37% >PMD: ixgbe_set_rx_function(): Vector rx enabled, please make sure RX >burst size no less than 32. >Total sent 26824256 recv 26823587, delta -669 The number of packets sent/recv are read from the NIC counters and Pktgen does not count the packets in anyway. The script could also be in error. I was just looking at the script and maybe the timing from stoping the transmit and reading the counters is the issue. You could try putting a delay before the counter read to make sure all of the packets have been sent/recv along with the reading of the packets. I do not have a setup to test it at this time. Regards, ++Keith > >Any hints will be really helpful, thanks! > >Thanks >--jyh