Hi, Please have a look at https://en.wikipedia.org/wiki/High_availability I was trying to calculate your link availability, but my Ubuntu calculator gives me 0 for 2 / 34 481 474 846 ;)
Most probably you dropped a packet during the start/stop. ierrors is what you NIC consider as an error Ethernet frame (checksums, runts, giants etc) Regards, Andriy On Mon, May 22, 2017 at 11:40 AM, <[email protected]> wrote: > Hi ! > > I performed many tests using Pktgen and it seems to work much better. > However, I observed that one of the tests showed that 2 packets were > dropped. In this test I sent packets between the 2 physical ports in > bidirectional mode during 24 hours. The packets size was 450 bytes and the > rate in both ports was 1500 Mbps. > > The port stats I got are the following : > > > ** Port 0 ** Tx: 34481474912. Rx: 34481474846. Dropped: 2 > ** Port 1 ** Tx: 34481474848. Rx: 34481474912. Dropped: 0 > > DEBUG portStats = { > [1] = { > ["ipackets"] = 34481474912, > ["ierrors"] = 0, > ["rx_nombuf"] = 0, > ["ibytes"] = 15378737810752, > ["oerrors"] = 0, > ["opackets"] = 34481474848, > ["obytes"] = 15378737782208, > }, > [0] = { > ["ipackets"] = 34481474846, > ["ierrors"] = 1, > ["rx_nombuf"] = 0, > ["ibytes"] = 15378737781316, > ["oerrors"] = 0, > ["opackets"] = 34481474912, > ["obytes"] = 15378737810752, > }, > ["n"] = 2, > } > > So 2 packets were dropped by port 0 and I see that "ierrors" counter has a > value of 1. Do you know what does this counter represent ? And what could it > be interpreted ? > By the way, I performed as well the same test changing the packet size to > 1518 bytes and the rate to 4500 Mbps (on each port) and 0 packets were > dropped. > > David > > > > > Le 17.05.2017 09:53, [email protected] a écrit : >> >> Thanks for your response ! >> >> I have installed Pktgen and I will perform some tests. So far it seems >> to work fine. I'll keep you informed. Thanks again. >> >> David >> >> Le 12.05.2017 18:18, Wiles, Keith a écrit : >>>> >>>> On May 12, 2017, at 10:45 AM, [email protected] wrote: >>>> >>>> Hi ! >>>> >>>> I am working with MoonGen which is a fully scriptable packet generator >>>> build on DPDK. >>>> (→ https://github.com/emmericp/MoonGen) >>>> >>>> The system on which I perform tests has the following characteristics : >>>> >>>> CPU : Intel Core i3-6100 (3.70 GHz, 2 cores, 2 threads/core) >>>> NIC : X540-AT2 with 2x10Gbe ports >>>> OS : Linux Ubuntu Server 16.04 (kernel 4.4) >>>> >>>> I coded a MoonGen script which requests DPDK to transmit packets from >>>> one physical port and to receive them at the second physical port. The 2 >>>> physical ports are directly connected with an RJ-45 cat6 cable. >>>> >>>> The issue is that I perform the same test with exactly the same script >>>> and the same parameters several times and the results show a random >>>> behavior. For most of the tests there is no losses but for some of them I >>>> observe packet losses. The percentage of lost packets is very variable. It >>>> happens even when the packet rate is very low. >>>> >>>> Some examples of random failed tests : >>>> >>>> # 1,000,000 packets sent (packets size = 124 bytes, rate = 76 Mbps) → >>>> 10170 lost packets >>>> >>>> # 3,000,000 packets sent (packets size = 450 bytes, rate = 460 Mbps) → >>>> ALL packets lost >>>> >>>> >>>> I tested the following system modifications without success : >>>> >>>> # BIOS parameters : >>>> >>>> Hyperthreading : enable (because the machine has only 2 cores) >>>> Multi-processor : enable >>>> Virtualization Technology (VTx) : disable >>>> Virtualization Technology for Directed I/O (VTd) : disable >>>> Allow PCIe/PCI SERR# Interrupt (=PCIe System Errors) : disable >>>> NUMA unavailable >>>> >>>> # use of isolcpus in order to isolate the cores which are in charge of >>>> transmission and reception >>>> >>>> # hugepages size = 1048576 kB >>>> >>>> # size of buffer descriptors : tried with Tx = 512 descriptors and Rx = >>>> 128 descriptors and also with Tx = 4096 descriptors and Rx = 4096 >>>> descriptors >>>> >>>> # Tested with 2 different X540-T2 NICs units >>>> >>>> # I tested all with a Dell FC430 which has a CPU Intel Xeon E5-2660 v3 @ >>>> 2.6GHz with 10 Cores and 2threads/Core (tested with and without >>>> hyper-threading) >>>> → same results and even worse >>>> >>>> >>>> Remark concerning the NIC stats : >>>> I used the rte_eth_stats struct in order to get more information >>>> about the losses and I observed that in some cases, when there is packet >>>> losses, ierrors value is > 0 and also ierrors + imissed + ipackets < >>>> opackets. In other cases I get ierrors = 0 and imissed + ipackets = >>>> opackets which has more sense. >>>> >>>> What could be the origin of that erroneous packets counting? >>>> >>>> Do you have any explanation about that behaviour ? >>> >>> >>> Not knowing MoonGen at all other then a brief look at the source I may >>> not be much help, but I have a few ideas to help locate the problem. >>> >>> Try using testpmd in tx-only mode or try Pktgen to see if you get the >>> same problem. I hope this would narrow down the problem to a specific >>> area. As we know DPDK works if correctly coded and testpmd/pktgen >>> work. >>> >>>> >>>> Thanks in advance. >>>> >>>> David >>> >>> >>> Regards, >>> Keith > > -- Andriy Berestovskyy
