[dpdk-users] Why is that the performance of bigger frame cannot achieve line rate while using DPDK

[MESSI SHIYEH]

Hi all,

English is not my native language, please excuse typing errors.

Now We have a platform like this:
CPU: Intel Xeon E3-1275v3 @3.5Ghz
DRAM: Samsung DDR3 4G * 2
OS: RHEL 6.4 x64
NIC: XL710 (4 ports * 10Gbps)
Lan driver: i40e-1.4.25

We used this platform to run Smartbit RFC2544 testing with 'testpmd' of
DPDK,
and the result shows that the throughput can not achieve line rate (100%)
from packet size 256 bytes to 1518 bytes, just 99.297%.

The version of DPDK what we used is 2.2.0, and the testing command is:
./testpmd -c 0x3c -n 4 -- -i --nb-cores=4 --portmask=0xf

Why is that?

PS.
We did not put a acceptable frame loss in our smartbit setting, just 0%,
and we checked details of the test report, it shows that there is few frame
loss (~0.001%) while running with 100% loading.


Best regards,
Leo,