Fuel Networking performance improvment: ethernet hardware rings

[Alexander Nevenchannyy]

Folks, we need to increase hardware rings at ethernet interfaces:
Current settings:
root@node-20:~# ethtool -g eth2
Ring parameters for eth2:
Pre-set maximums:
RX: 4096
RX Mini: 0
RX Jumbo: 0
TX: 4096
Current hardware settings:
RX: 512
RX Mini: 0
RX Jumbo: 0
TX: 512

So we need to increase rings to maximum that support hardware.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/235937

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/235937
Committed: https://git.openstack.org/cgit/openstack/fuel-library/commit/?id=effc358becfef9ab02b601a168642aa4eb6fef68
Submitter: Jenkins
Branch: master

commit effc358becfef9ab02b601a168642aa4eb6fef68
Author: Michael Polenchuk <email address hidden>
Date: Fri Oct 16 17:09:04 2015 +0300

    Set rings rx/tx to maximum that supports hardware

    All recent versions of the chipset have 4096, but the driver doesn't
    autodetect this. Increasing the number of descriptors can improve
    performance dramatically on some hosts.

    This is also the case with Intel 10GE NICs - the driver defaults to 256
    descriptors each for Rx and Tx, even if the hardware supports 4096.

    Depends-On: Ib70ae937165ddb2968c9e4346434f18778b31714
    Change-Id: I1e5029e793399ff42002f3d203c6ae3bd2608be2
    Closes-Bug: #1456723

[Sergey Vasilenko (xenolog)]

As I found into git logs, this fix merged only into master branch (Newton) and does not backported to stable/mitaka. I marked Mitaka series "Won't fix" because this bug has Low priority and code freeze coming.

[Andrew Kalach (akndex)]

In 9.0 RC2 is reproducible (actual value is less than max available), "Won't fix" confirmed.