By: Jenifer Hopper. More details on CPU utilization issues
I recently posted about a RHEL6.3 kernel update that resolves a CPU utilization bug in this blog . Since then I have received a few questions asking for more details, so I want to share those here. Q: The problem was in /proc/stat? What was the issue? A: Yes, there was a bug that caused incorrect idle and iowait values to be displayed in /proc/stat. The main issue was a change that caused an incorrect divisor to be used (msec vs. usec). Q: Do I need to update my profiling... [More]
By: Jenifer Hopper.
Fixing CPU utilization metrics on RHEL 6.3
As reported earlier in a blog post , the standard RHEL 6.3 kernel has issues with correctly calculating CPU utilization values .
(For more insights into the fix below, see a different blog post )
** Note: The specific zstream kernel version mentioned in this article was the most recent at the time of publication. Newer RHEL 6.3 zstream kernel releases should contain this... [More]
By: Rafael Folco. Practical experiences with setting up a cluster
I recently have had the opportunity to work with the IBM InfoSphere BigInsights product on PowerLinux. From these experiences, I created a wiki page which describes some hints and tips on setting up a cluster for BigInsights. The BigInsights product provides for serious hadoop-based processing and is available on the PowerLinux base. If you have questions on taking advantage of BigInsights and hadoop on Power systems, ask a question on the PowerLinux message... [More]
By: Beth Taylor. As of today, IBM® Software Development Kit for PowerLinux 1.2 is now available for download from the IBM Software Development Toolkit for PowerLinux page About IBM Software Development Toolkit for PowerLinux 1.2 IBM SDK for PowerLinux is a free, Eclipse-based Integrated Development Environment (IDE) for application development on IBM PowerLinux™ and IBM Power Systems™ servers running Linux. The IBM SDK for PowerLinux integrates C/C++ source development with the IBM Advance Toolchain for PowerLinux and classic Linux... [More]
By: Jeff Scheel. My customer presentation last week in Livermore, CA allowed me to take PowerLinux to "new depths" by presenting in a wine cellar! Check out the photo of the cellar entrance I posted out in Google+. While you're out there, feel free to follow
Jeff Scheel on
Besides the unique location, this event really forced me to consolidate my thoughts into a concise message on PowerLinux. Here were the 3 main points (all good things come in three's...it's the "magic number"): PowerLinux... [More]
By: Bill Buros. So this is very nice. The good team over on Power IT pro has been steadily increasing the presence of technical information around Linux and Power systems. I follow their email newsletter and enjoy the technical hints and tips they provide. Yesterday, Erwin Earley started a new blog on PowerITpro focused specifically on the world of Linux and Power. Quoting from their latest page: Introducing Our New Power Linux Blog We're starting a new POWER IT Pro blog targeted specifically at those who are responsible for... [More]
By: Carlos Seo. The IBM Advance Toolchain for PowerLinux is a set of open source development tools and runtime libraries which allows users to take leading edge advantage of IBM's latest POWER hardware features on Linux. A new update release is now available, and it features: Bug fixes for DFP in GCC. Fix to address over counting user context lost samples in Oprofile. GDB now displays correctly the vperm instruction. Time zone for the Advance Toolchain is now automatically set to the system's time zone. New advance-toolchain-at5.0-selinux rpm,... [More]
By: Jeff Scheel.
Today's common question comes to us from many different sources. What prompts the write-up today is a nice description I recently saw in an email. Question: How hard is it to migrate applications to PowerLinux?
Answer: It depends on the characteristics of the application, but generally speaking migration is simple and straightforward. Post migration, the real work can be in tuning performance sensitive applications which typically contain more assembler and non-portable, platform-unique code, two attributes which... [More]
By: Bill Buros. If you've updated to the most recent RHEL 6.3, you might be seeing issues with CPU utilization being reported to the end users.
# uname -r 2.6.32-279.el6.ppc64 With the kernel here, if you run "top" on an idle system, it may report clearly inaccurate CPU utilization metrics, as in the idle system below. 66% kernel time on an idle system is not accurate.
# top top - 16:05:04 up 1 day, 39 min, 2 users, load average: 0.00, 0.00, 0.00 Tasks: 1167 total, 1 running, 1166 sleeping, 0 stopped, 0... [More]
By: Carlos Seo. The IBM Advance Toolchain for PowerLinux is a set of open source development tools and runtime libraries which allows users to take leading edge advantage of IBM's latest POWER hardware features on Linux. A new major release is now available, and it features: New base toolchain, based on gcc-4.7.2 and glibc-2.16 Supported on SLES 11 and RHEL 6 only (and their respective Service Packs and Updates) Optimized libraries for POWER7 only gcc now defaults to -mcpu=power6 -mtune=power7 Oprofile now supports non-root single... [More]
By: Jessica Erber-Stark. They say a picture is worth a thousand words. If that's true, how many words is an information-packed video worth? The PowerLinux team has been hard at work, creating several videos to educate you on many aspects of the PowerLinux product. From product overviews to detailed technical demos, we can almost guarantee that you'll come away from these videos saying, "I didn't know I could do that with PowerLinux!" Check out the videos in the wiki at the PowerLinux videos page. We'd also love to hear your... [More]
By: Steve Champagne. Thanks to all who participated in the Kernel notifications for RHEL 5 running on 7R2 thread in the Message Board! Your conversation and insights led to the following new topic in the Linux Information Center: Diagnosing RTAS events .
By: Steve Champagne. For information about performance tuning on your PowerLinux system, be sure to see the A Tuning Guide for PowerLinux section of Performance Rocks - Best Practices . I added three new sections there today:
Tuning Guide: Compilers and Optimization Tools for C/C++/Fortran
Tuning Guide: Empirical Performance Analysis using the IBM SDK for PowerLinux
Tuning Guide: Deeper Empirical Analysis for improving performance
By: Carlos Seo. The IBM Advance Toolchain for PowerLinux is a set of open source development tools and runtime libraries which allows users to take leading edge advantage of IBM's latest POWER hardware features on Linux. A new release is now available, and it features: Performance improvements for tcmalloc Bug fixes for DFP support in Valgrind For download links, more information and documentation, please refer to our official documentation page . Please let us know if you have any questions about this release.
By: Peter Wong. Understanding Systems and Architectures for Big Data IBM Research with various organizations have recently updated the paper " Understanding Systems and Architectures for Big Data " originally published in April 23, 2012, based on new data collected on 10 PowerLinux 7R2 systems running IBM InfoSphere BigInsights v1.3. Note that the new paper starts at Page 2. The contact author is Jian Li (jianli at us.ibm.com) in IBM Research in Austin. This paper provides tuning tips for tuning TeraSort on PowerLinux systems at... [More]