RHBA-2012:0495 - Bug Fix Advisory

Topic

Updated Red Hat Enterprise MRG Realtime packages that fix several bugs are now
available for Red Hat Enterprise MRG 2.1.

Red Hat Enterprise MRG (Messaging, Realtime, and Grid) is a next-generation IT
infrastructure for enterprise computing. MRG offers increased performance,
reliability, interoperability, and faster computing for enterprise customers.

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.

Description

This update provides bug fixes for the following packages:

• The ibm-prtm package contains a utility and a start-up script for IBM

BladeCenter systems. It enables the EDAC (Error Detection and Correction) driver
and also turns off the System Management Interrupts (SMI) generation, which
improves system response time to events.

• The rteval package contains a utility for measuring various aspects of

real-time behavior on systems under load. The script unpacks the hackbench
stress test and benchmark utility, and the kernel source code from the
rteval-loads package, builds hackbench, and then goes into a loop, running
hackbench and compiling a kernel tree. During that loop, the cyclictest program
is run to measure event response times. After the run time completes, a
statistical analysis of the event response times is performed and printed to the
screen.

• The rt-setup package configures settings required by the Red Hat Enterprise

Linux real-time environment, such as creating the realtime group, adding
realtime user privileges to PAM (Pluggable Authentication Models), enabling the
configuration of kdump in real time, and disabling irqbalance by default.

• The tuna package provides graphical and command-line interfaces for changing

scheduler and interrupt request (IRQ) settings. Changes can be made to CPUs, by
thread or at the IRQ level, taking into account the topology of multi-socket and
multi-core systems. Tuna provides the ability to isolate CPU cores and sockets
for use by a specific application or hardware device.

Bug fixes:

• Signal handlers were commented out during debugging session and not restored

for release, which caused the early termination logic to fail. Now, the signal
handling logic has been restored and the early termination logic works
appropriately. (BZ#574166)

• The cyclictest test always ran with the --smp option rather than --numa on

appropriate systems because the numanode parameter was not correctly passed to
the child process. This bug has been fixed and cyclictest now uses the correct
option when starting measurement threads. (BZ#773075)

• SMI remediation was not working correctly, resulting in error messages at boot

due to an incorrect patch applied to the base ibm-prtm script. This update
provide an appropriate patch that fixes SMI remediation on IBM non-EFI systems
and the error messages are no longer returned. (BZ#767605)

• Tuna now contains a man page that is correctly displayed with the command 'man

tuna'. (BZ#545539)

• Some udev rules added by MRG Realtime were being called at a much higher

frequency than anticipated, which could cause inordinately long boot times on
systems with more than 15 cores. Now, child process creation has been removed
from the Realtime udev rules and the boot times are shorter on such systems.
(BZ#698481)

• Previously, the Realtime bandwidth limiting feature for SCHED_FIFO/SCHED_RR

threads was disabled. Consequently, various issues occurred in some
CPU-intensive applications that depend on this feature. Now, this feature has
been enabled and SCHED_OTHER threads get 5% of the CPU time on cores that are
monopolized by SCHED_FIFO/SCHED_RR threads.

Note that when upgrading from a previous installation of rt-setup,
/etc/sysctl.conf must be manually edited to remove the kernel.sched_rt_realtime*
lines, which disable bandwidth limiting. (BZ#791371)

• The ibm-prtm package installs a configuration file in the /etc/modprobe.d/

directory. Prior to this update, the modprobe utility displayed the following
warning message:

WARNING: All config files need .conf: /etc/modprobe.d/ibm-amd, it will be
ignored in a future release.

With this update, the configuration file has been renamed to ibm-amd.config,
thus fixing this bug. (BZ#710503)

Users of the real-time capabilities of Red Hat Enterprise MRG 2.1, which is
layered on Red Hat Enterprise Linux 6, are advised to upgrade to these updated
packages, which fix these bugs.

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 - 545539 - tuna does not have a man-page
• BZ - 574166 - rteval: add early termination logic
• BZ - 698481 - x3950 X5 hangs at udev for 3 hours
• BZ - 710503 - ibm-prtm installs modprobe file with wrong extension on RHEL6
• BZ - 773075 - rteval does not propagate parameter changes to cyclictest object

CVEs

(none)

References

(none)