[dts] [PATCH V3] add TREX support in DTS framework

[Liu, Yong]

Thanks, fei. Applied into next branch.

On 01/10/2018 12:53 PM, wang fei wrote:
> For next branch framework/tester.py: enabling trex for DTS and
> implement througput function for performace test.
>
> Signed-off-by: wang fei<feix.y.wang at intel.com>