Hi Alex,
thanks for your reply. I used an Agilent N2X packet generator to generate
and send TCP packets. The generator could be configured to send all kinds of
network packets. I configured it to send 150 byte long TCP packets, 7.35M
packets per second (about 10Gbps). The sended TCP packets have normal format:
EthernetHeader + IPHeader + TCPHeader + TCPPayload
The TCP header of packets is configured as below:(every sended packet has same
configuration)
TCP Header:
Source port: [1-2000, Increment]
Destination port: [1-2000, Increment]
Sequence number 0
Ackowledge number 0
Data offset: 5
Reserved: 0x00
Code Bits:
URG: 0
ACK: 1
PSH: 0
RST: 0
SYN: 0
FIN: 0
Window Size: 0
Checksum: 0x2D71 (automated, differ
from packet)
Urgent pointer: 0
TCP options: None
Sending packets with above configuration causes a lot of rx_missed_error(drop)
at the receiving 82599 NIC. But if I just set any flag(in Code Bits field)
other than ACK to 1, there would be no errors or drops.
Thanks,If any other info is needed, please let me known.
Dillan
在 2012-12-21 02:03:15，"Alexander Duyck" <alexander.h.du...@intel.com> 写道：
>On 12/20/2012 05:56 AM, 周介龙 wrote:
>> Hi all,
>> I am testing the receive side performance of a 82599EB NIC, using the
>> newest stable driver ixgbe3.11. When receiving 10Gbps tcp pkts with (and
>> only with) ACK flag, I found a lot of drop statistics in the result of
>> ifconfig command and rx_missed_error in the result of ethtool -S. And the
>> cpu utilized percent if less than 40%. If tcp pkts have any flag other than
>> ACK, or have any optional tcp header, the NIC would never drop any pkts. I
>> think it may be caused by RSC feature, but after disabling RSC by "ethtool
>> -C eth* rx-usecs 0" or adding MACRO "-DIXGBE_NO_HW_RSC" in Makefile, the NIC
>> still drops pkts. Also, the RFCTL.RSC_DIS register can not be set to 1. I
>> have also run the same test on different motherboards, CPUs, kernels, and
>> drivers, and got the same result... This problem has been puzzling me for a
>> few months, is there any way to solve it?
>> Thanks,
>> Dillan Zhou
>>
>
>Hi Dillan,
>
>It would help if you could explain your test setup. For example how is
>it you are generating the TCP frames with the ACK flag set? Also what
>rate is it you are sending these packets at?
>
>Thanks,
>
>Alex
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