RHBA-2015:2664 - Bug Fix Advisory

Topic

Updated Red Hat Enterprise MRG Realtime packages that provide one bug fix are
now available for Red Hat Enterprise MRG 2.5.

Description

MRG Realtime provides the highest levels of predictability for consistent
low-latency response times to meet the needs of time-sensitive workloads. MRG
Realtime provides new levels of determinism by optimizing lengthy kernel code
paths to ensure that they do not become bottlenecks. This allows for better
prioritization of applications, resulting in consistent, predictable response
times for high-priority applications.

This update fixes the following bug:

• The rteval tool uses the hackbench utility to place a load on the system to

exercise memory allocation, free and memory copies. Prior to this update, rteval
started its loads across the entire set of CPUs, which generated large amounts
of cross-node memory traffic. As a consequence, latency spikes could occur. With
this update, hackbench has been modified to run a single instance for each
Non-Uniform Memory Acces (NUMA) node in the system to better reflect common
system tuning for a real-time environment, and the latency spikes no longer
occur. (BZ#1284980)

Users of the real-time capabilities of Red Hat Enterprise MRG 2.5, which is
layered on Red Hat Enterprise Linux 6, are advised to upgrade to these updated
packages which fix this bug.

Solution

Before applying this update, make sure all previously released errata relevant
to your system have been applied.

This update is available via the Red Hat Network. Details on how to use the Red
Hat Network to apply this update are available at
https://access.redhat.com/knowledge/articles/11258

Affected Products

• MRG Realtime 2 x86_64

Fixes

• BZ - 1284980 - [MRG] hackbench: modify to run within NUMA node to avoid cross-node traffic

CVEs

(none)

References

(none)