RHBA-2015:1367 - Bug Fix Advisory

Topic

Updated oprofile packages that fix several bugs and add one enhancement are now
available for Red Hat Enterprise Linux 6.

Description

OProfile is a low-overhead, system-wide profiler that uses the performance
monitoring hardware on the processor to retrieve information about the kernel
and executables on the system.

This update fixes the following bugs:

• Previously, when profiling performance of Java just-in-time (JIT) compiled

code with static huge pages enabled, OProfile's operf command recorded a large
number of event samples to anonymous memory (in anon_hugepage) instead of to the
appropriate Java method. With this update, operf recognizes the static huge page
identifiers and correctly maps samples to Java methods when using statically
allocated huge pages. (BZ#1180513)

• To properly select an event, some new Intel processors require not only the

base event number but also additional bits to be set in the unit mask.
Previously, the additional bits in the unit mask remained unset, thus being
incorrectly set to zero. As a consequence, performance monitoring hardware was
not measuring the desired event, and the operf utility returned zero for the
LLC_REFS and LLC_MISSES events on the 2nd, 3rd, and 4th generation Intel Core
and Intel Xeon processors. With this update, OProfile code has been fixed to set
the unit mask bits as required. As a result, performance events on Intel
processors that require non-zero unit masks now work as expected. (BZ#1199469)

• Previously, when a name of the default unit mask for an event was longer than

11 characters, OProfile truncated the name to 11 characters. Consequently, when
the truncated unit mask name was used, OProfile could not find the unit mask and
returned an error message. With this update, OProfile handles long unit mask
names correctly, and the described problem no longer occurs. (BZ#1200808)

• The operf, ocount, and opjitconv utilities set the POSIXLY_CORRECT enviroment

variable for their internal purposes. Prior to this update, OProfile did not
return this environment variable to its previous state, thus potentially
affecting profiled tasks. Consequently, profiled tasks that behaved differently
when the variable was set, such as rpm rebuilds, did not work as expected. This
bug has been fixed, and the OProfile use of POSIXLY_CORRECT now does not affect
profiled tasks. (BZ#1202727)

In addition, this update adds the following enhancement:

• The OProfile profiler tool now includes support for Intel Silvermont events

for the Intel Atom C2XXX and Intel Atom E38XX systems on a chip (SoC). This
allows users to investigate Intel Silvermont-specific performance issues using
OProfile. (BZ#1144235)

Users of oprofile are advised to upgrade to these updated packages, which fix
these bugs and add this enhancement.

Solution

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

For details on how to apply this update, refer to:

https://access.redhat.com/articles/11258

Affected Products

• Red Hat Enterprise Linux Server 6 x86_64
• Red Hat Enterprise Linux Server 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 i386
• Red Hat Enterprise Linux Workstation 6 x86_64
• Red Hat Enterprise Linux Workstation 6 i386
• Red Hat Enterprise Linux Desktop 6 x86_64
• Red Hat Enterprise Linux Desktop 6 i386
• Red Hat Enterprise Linux for IBM z Systems 6 s390x
• Red Hat Enterprise Linux for Power, big endian 6 ppc64
• Red Hat Enterprise Linux for Scientific Computing 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support (for IBM z Systems) 6 s390x

Fixes

• BZ - 1180513 - Unable to profile jit'd JVM code when using static huge pages

CVEs

(none)

References

(none)