T-Rex: 2.82, core pin, 8 workers

T-Rex: 2.82, core pin, 8 workers

+ Bump T-Rex version. We need new features for ASTF test.
+ Apply core pining. Results in a more stable performance.
+ Tweak the number of T-Rex workers.
 + We need an even value to achieve ymmetric performance with pinning.
 + Value 8 was selected as a best compromise.

This is a combination of 3 commits.
This is the 1st commit message:

T-Rex: 2.82

This is the commit message #2:

Change Trex to CORE_MASK_PIN mode to improve performance

https://trex-tgn.cisco.com/trex/doc/trex_stateless.html#_core_masking_per_interface
Above link have below explaination,

"When the profile is symmetric, performance can be improved by pinning half of
the cores to port 0, and half of the cores to port 1, thus avoiding cache
trashing and bouncing."

The reason to change this is that to run CSIT with 100G NIC often failed with
"TRex stateless runtime error timeout", it caused by Trex can not send enough
traffic within the fixed duration.

by change to CORE_MASK_PIN mode fix the issue.

Not editing ASTF, as that supports different options.

This is the commit message #3:

Experiment: Vary number of TRex workers

With CORE_MASK_PIN, we can get more predictable time distribution.
Decided to use 8 workers, that gives good results
both for high end (RDMA-core l2patch) and low end (vhost) tests.

Change-Id: I5c61127799e0624464e960fcb980ad1c4058e744
Signed-off-by: pmikus <pmikus@cisco.com>
Signed-off-by: Yulong Pei <yulong.pei@intel.com>
Signed-off-by: Vratko Polak <vrpolak@cisco.com>