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, dfernandes at toulouse.viveris.com 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, dfernandes at toulouse.viveris.com 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