Featuring guest blogger from Sun Microsystems, Darryl Gove.

The release of a new version of Sun Studio is always an exciting moment for Sun Studio enthusiasts. Sun Studio 12 came out pretty much two years ago, and a lot has changed in that time.

One particular trend has been that multicore processors have become mainstream. One way of illustrating that is to look at the number of threads per chip for all the submitted SPEC® CPU2006 integer speed results*. The following chart shows the cumulative number of submitted results since the benchmark came out in 2006 until the middle of June 2009 broken down by the number of threads that the chip could support.

Two years ago, when Sun Studio 12 came out, chips that could support two threads were starting to become common. Now we're looking at that being a minimal thread count, and we're starting to see the ramp up of threads that can support more than 4 threads - the latest AMD processors support six threads per chip. In tandem with the growth in thread count, we're seeing much more interest in developing applications that can use this core count. Sun is fortunate that with Solaris and Sun Studio, we have a very comprehensive, and long standing, investment in multiprocessor technology:. from virtualisation, through Zones, to scalability to huge core counts.

Sun Studio has always been on the leading edge of developing parallel applications. There are two ways of leveraging multiple cores, either through libraries provided with the compiler or through the parallisation of your application. For those people using the Performance Library, this is now optimised to take advantage of the latest AMD Quad-core and Six-core processors.

The easiest way of producing parallel code is using automatic parallelisation. Sun was the first company to submit automatically parallelised results for SPEC® CPU2000. Automatic parallelisation is a great technology. It takes some of the work of making parallel codes away from the developer, and places it firmly into the category of "just another compiler flag".

However, the compiler can't do this for all codes, which is why Sun was also one of the first companies to support the OpenMP 3.0 specification.

The OpenMP 3.0 specification is a very important step in making parallel programming easier. The 2.5 specification that was supported by Sun Studio 12 allows developers to identify loops that can be performed in parallel, and different sections of code that can be run simultaneously. The big improvement in the 3.0 specification is the support for Tasks. A task is a unit of work that one thread can request another thread to do. The developer defines the tasks in the source code, but the executed tasks and their order is dynamically determined at runtime. This massively increases the range of applications that can be parallelised using OpenMP.

Of course, writing parallel applications becomes much harder without the tools to support this. Sun Studio 12 Update 1 includes these tools. The Debugger for diagnosing bugs in parallel applications, the Performance Analyzer for determining the activity of all the threads in an application, and the Thread Analyzer for identifying data races in parallel applications. The Performance Analyzer has been enhanced to support hardware counters in the latest AMD processors. The hardware performance counters are an optimal way of determining exactly what the processor is doing during the run of your application.

Performance is often one of the motivating factors for any compiler upgrade. In a compiler suite performance comes from two sources: enabling the developer to identify opportunities to improve performance, and the ability of the compiler to produce good code for the processor. The performance analyzer is able to profile all kinds of parallel applications including those parallelised with OpenMP directives as well as distributed MPI applications. This enables you to quickly determine where, at a source code level, the application is spending its time, and to drill down into that source to understand the performance at the level of hardware events.

The goal for the Sun Studio compiler has always been to produce code that runs as fast as possible on all SPARC and x86 processors. Sun has worked closely with AMD to ensure that the compiler is aware of the best practices for producing code for the latest AMD processors. Sun Studio 12 Update 1 includes this support and continues the long track record of delivering superior performance on AMD processors.

As well as providing support for all processors, Sun Studio is also supported on a number of platforms: Solaris, OpenSolaris, and Linux (for x86). Perhaps most importantly Sun Studio 12 Update 1 is free of charge to download and use.

* SPEC and the benchmark names SPECfp and SPECint are registered trademarks of the Standard Performance Evaluation Corporation.  Benchmark results stated above reflect results posted on www.spec.org as of 15 June 2009.

Darryl Gove is a Senior Staff Engineer in the compiler team at Sun Microsystems. He works on the optimisation and tuning of applications and benchmarks. He is the author of the books "Solaris Application Programming" and "The Developers Edge," and maintains a blog at http://blogs.sun.com/d/. His postings are his own opinions and may not represent AMD's positions, strategies or opinions. Links to third party sites are provided for convenience and unless explicitly stated, AMD is not responsible for the contents of such linked sites and no endorsement is implied.

The information presented in this document is for informational purposes only and may contain technical inaccuracies, omissions and typographical errors. Links to third party sites are for convenience only, and no endorsement is implied.