By: Bill Buros. There's quite a bit going on in the world of Linux on Power, where several of us have some focus on improvements for performance. Lately, a series of articles have been published on DeveloperWorks which nicely highlight the performance gains that gcc (packaged in the Advance Toolchain) provides over the gcc packaged with the Linux operating system. Two articles are available which dive into performance gains across a number of workloads embedded in the SPECcpu2006 suite. The approach is simple. Use gcc as bundled with the... [More]
By: Jenifer Hopper, working closely with zswap developer: Seth Jennings Updates: Results for the new POWER7+ compression accelerator are provided inline A related article by Seth available on LWN.net: The zswap compressed swap cache With a short article here, we introduce some good work going on in the Linux community for memory compression techniques on a Linux system. A new proposed framework called " zswap " is discussed, with some initial performance data provided to demonstrate the potential benefits for a system... [More]
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: Steve Dobbelstein.
On February 22, 2013, IBM® published a new SPECjEnterprise®2010 result on a two socket system. The result was achieved on the new IBM PowerLinux™ 7R2 system using IBM WebSphere® Application Server v8.5 and IBM DB2® 10.1 running on Red Hat® Enterprise Linux® release 6.4. The Linux Technology Center (LTC) team, the WebSphere team, the Java team, and the DB2 team all worked together to analyze and tune the performance of the... [More]
By: Maynard Johnson and Beth Taylor. Finding performance bottlenecks in applications that you develop can be a daunting task. But with the right tools and a little guidance, it's easier than you might think. OProfile is a performance analysis tool set for Linux systems. A new collection of topics has been published in the Linux for IBM Systems Information Center to help application developers get started with OProfile on Power Systems™ servers running Linux. Getting started with OProfile on PowerLinux introduces the new operf... [More]
By: Beth Taylor and Walt Madden. Several previous blog posts have told of the
advantages of IBM ®
Advance Toolchain for PowerLinux for application performance analysis on IBM
Power Systems ™
servers. Likewise, you've heard about
IBM Software Development Kit for PowerLinux ™ , which combines C/C++ source
development with the Advance Toolchain and classic Linux debugging and
performance analysis tools like OProfile. Recently, the IBM InfoSphere Streams development
team has had the positive experience to give credit to these claims... [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: Bill Buros. Continuing our journey into benchmarks, we recently were working on the SPECcpu2006 set of benchmarks again, and returned to look at some of the dependent products which we build and run with. One of the products which we link with on Power Linux is MicroQuil's Smartheap library. This is a run-time library which can be purchased from MicroQuil. One of the benchmark components of the SPECcpu2006 suite - xalancbmk - is a classic example of a questionable choice as a system and compiler measurement benchmark. The... [More]
By: Jessica Erber-stark. Check out the Linux Information Center for new information about Improving performance with Advance Toolchain 4.0 About the Advance Toolchain : The Advance Toolchain provides early and easy access to
libraries and the latest compiler technologies for Linux distributions. Over time, these libraries
and latest compiler technologies are integrated into the shipping
distributions. However, the Advance Toolchain contains the latest
tested and supported GNU Compiler Collection (GCC) compiler versions,
tailored for... [More]
Last week a new SAP Sales and Distribution (SD) Standard Application Benchmark result was published on the SAP benchmark site ( here ). The result was produced with SLES 11 sp1 running on an IBM Power 730 12-core system. What's particularly cool for us is the result was produced with gcc 4.3.4 as shipped with the SLES 11 distro. For more information on general SAP tunings, an IBM InfoCenter Blueprint paper was published which explains how to tune an SAP implementation on Linux on Power. The article describes common system tunings, as... [More]
By: Anirban Chatterjee.
month, the PowerLinux team is announcing the biggest technology change in PowerLinux servers
since we launched, with the availability of our POWER7+ chips on the platform.
POWER7+ is more than just a speed bump on our POWER7
processors. Our hardware teams have
worked hard to increase the flexibility of the platform, bringing
balanced performance increases while keeping other factors like energy
consumption at bay. Some examples:
doubled the memory capacity in... [More]
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.
Malloc. Simple. Can I optimize it? By: Bill Buros. With some recent questions and interactions around malloc performance, a number of people consolidated some thoughts and ideas around the basic notion of optimizing "malloc" and memory usage. While these guidelines and recommendations should be generally applicable, in this case we focused on Linux applications running on Power. For more details, see the newest performance article on " Tuning and optimizing malloc on PowerLinux ". Let us know if you have... [More]