Need Java 7? We got Java 7. By: Bill Buros. Last year we posted that the IBM Java 7 was in open beta mode, but along the way we neglected to post the news that the IBM Java 7 kits are now fully available across a number of platforms and operating systems. By now, this is relatively older news, IBM Java 7 was announced back in September 2011, but it's always good to remind people and teams that it's available. This latest IBM Java is available on Power systems and across the RHEL and SLES distros available for Power. We use the latest... [More]
By: Bill Buros. This morning we got into a good discussion on what simple things that we check on a new system or partition for Power Linux.
The list was easy. How many cores? what SMT mode are the cores running in? how fast are the cores running? how much memory is available? how is the memory balanced? and is any of the memory tied up in Hugepages?
So we wrote a quick script here to get that information and thought we'd post that here. Edit'ed Aug 3rd 2012: See a new article " Setup and understand your system " for a more... [More]
zswap" is discussed, with some initial performance data provided to demonstrate the potential benefits for a system (partition or guest) which has constrained memory and is beginning to swap memory pages to disk. The technique improves the throughput of a system, while significantly reducing the disk I/O activity normally associated with page swapping. We also explore how zswap works in conjunction with the new compression accelerator feature of the POWER7+ processor to potentially improve the system throughput even more... [More]
By: Jenifer Hopper
This article discusses some basic XML tuning tips for PowerKVM guests. It helps new users get started with editing guest XML definitions, and walks through some simple tuning examples.
The article covers various options to tune the guest disk, network, cpu, and memory. It also includes some example guest resource pinning configurations for different scenarios. Applying these tips may help improve application performance by ensuring your guest is configured properly and optimized for... [More]
By: Bill Buros. In the continuing journey of performance improvements with GCC, numerous development and performance teams recently hit an interesting milestone with results taking advantage of GCC compilers. The bottom-line difference between similar publishes of SPECint_rate_base2006 has broken the 10% difference milestone on Base measurements. These results are taking advantage of GCC-4.6.1-ibm-r176948 build. The bottom-line difference is calculated by taking the scores of 12 different programs and doing something called a "... [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: Bill Buros. Continuing our theme of leveraging gcc for performance based workloads, here we point to a couple of recent Linpack results from the Top500 web site. The Top500 site tracks the results of Linpack runs from small single standalone servers all of the way up through the Top 500 supercomputers in the world. Naturally, the smaller results are buried in a very big table somewhere on the site, but the Top500 entries are listed separately. What’s noteworthy in the two results below is that "gcc" was leveraged to build... [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: Jenifer Hopper
This article explains an example method to tune a full-system PowerKVM guest to achieve CPU and memory performance that is very close to non-virtualized speeds, demonstrating very low KVM overhead on a POWER8 system. It also provides some common tuning tips for running SPECjbb2005 and the STREAM memory bandwidth workload on POWER8 systems.
The example tutorial starts by measuring non-virtualized performance to provide a system baseline (non-virtualized mode is currently a technical... [More]
By: Jenifer Hopper
Are you interested in better understanding memory access performance? A new article, Untangling memory access measurements - memory latency explains how to use an example benchmark called lat_mem_rd to measure memory read latency on IBM® Power Systems™ servers running Linux.
This article takes a practical approach to measuring memory latency performance, from understanding initial results to moving on to examining the effects of more... [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: 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]