Last updated: $Date: 2012-10-11 13:43:55 -0400 (Thu, 11 Oct 2012) $ by $Author: BrianWhitney $
(To check for possible updates to this document, please see http://www.spec.org/omp2012/Docs/ )
This document provides background information about the SPEC OMP2012 benchmark suite. SPEC hopes that this material will help you understand what the benchmark suite can, and cannot, provide; and that it will help you make efficient use of the product.
Overall, SPEC designed SPEC OMP2012 to provide a comparative measure of compute intensive performance across the widest practical range of hardware. The product consists of source code benchmarks that are developed from real user applications. These benchmarks depend on the processor, memory and compiler on the tested system.
This document is organized as a series of questions and answers.
Q1. What is SPEC?
Q2. What is a benchmark?
Q3. Should I benchmark my own application?
Q4. If not my own application, then what?
Q5. What does SPEC OMP2012 measure?
Q6. Why use SPEC OMP2012?
Q7. What are the limitations of SPEC OMP2012?
Overview of usage
Q8. What is included in the SPEC OMP2012 package?
Q9. What does the user of the SPEC OMP2012 suite have to provide?
Q10. What are the basic steps in running the benchmarks?
Q11. What source code is provided? What exactly makes up these suites?
Q12. Some of the benchmark names sound familiar; are these comparable to other programs?
Q13. What metrics can be measured?
Q14. What is the difference between a "base" metric and a "peak" metric?
Q15. What is the power metric?
Q16. Which SPEC OMP2012 metric should be used to compare performance?
OMP2012 vs. OMP2001
Q17. SPEC OMP2001 is already available. Why create SPEC OMP2012? Will it show anything different?
Q18. What happens to SPEC OMP2001 after SPEC OMP2012 is released?
Q19. Is there a way to translate SPEC OMP2001 results to SPEC OMP2012 results or vice versa?
Q20. What criteria were used to select the benchmarks?
Q21. Weren't some of the SPEC OMP2012 benchmarks in SPEC OMP2001? How are they different?
Q22. Why were some of the benchmarks not carried over from OMP2001?
Q23. Why does SPEC use a reference machine? What machine is used for SPEC OMP2012?
Q24. How long does it take to run the SPEC OMP2012 benchmark suites?
Q25. What if the tools cannot be run or built on a system? Can the benchmarks be run manually?
Q26. Where are SPEC OMP2012 results available?
Q27. Can SPEC OMP2012 results be published outside of the SPEC web site? Do the rules still apply?
Q28. How do I contact SPEC for more information or for technical support?
Q29. Now that I have read this document, what should I do next?
Note: links to SPEC OMP2012 documents on this web page assume that you are reading the page from a directory that also contains the other SPEC OMP2012 documents. If by some chance you are reading this web page from a location where the links do not work, try accessing the referenced documents at one of the following locations:
SPEC is the Standard Performance Evaluation Corporation. SPEC is a non-profit organization whose members include computer hardware vendors, software companies, universities, research organizations, systems integrators, publishers and consultants. SPEC's goal is to establish, maintain and endorse a standardized set of relevant benchmarks for computer systems. Although no one set of tests can fully characterize overall system performance, SPEC believes that the user community benefits from objective tests which can serve as a common reference point.
A benchmark is "a standard of measurement or evaluation" (Webster’s II Dictionary). A computer benchmark is typically a computer program that performs a strictly defined set of operations - a workload - and returns some form of result - a metric - describing how the tested computer performed. Computer benchmark metrics usually measure speed: how fast was the workload completed; or throughput: how many workload units per unit time were completed. Running the same computer benchmark on multiple computers allows a comparison to be made.
Ideally, the best comparison test for systems would be your own application with your own workload. Unfortunately, it is often impractical to get a wide base of reliable, repeatable and comparable measurements for different systems using your own application with your own workload. Problems might include generation of a good test case, confidentiality concerns, difficulty ensuring comparable conditions, time, money, or other constraints.
You may wish to consider using standardized benchmarks as a reference point. Ideally, a standardized benchmark will be portable, and may already have been run on the platforms that you are interested in. However, before you consider the results you need to be sure that you understand the correlation between your application/computing needs and what the benchmark is measuring. Are the benchmarks similar to the kinds of applications you run? Do the workloads have similar characteristics? Based on your answers to these questions, you can begin to see how the benchmark may approximate your reality.
Note: A standardized benchmark can serve as reference point. Nevertheless, when you are doing vendor or product selection, SPEC does not claim that any standardized benchmark can replace benchmarking your own actual application.
SPEC OMP2012 focuses on compute intensive performance, which means these benchmarks emphasize the performance of:
It is important to remember the contribution of the latter three components. SPEC OMP performance intentionally depends on more than just the processor.
SPEC OMP2012 contains a suite that focuses on parallel computing performance using the OpenMP parallelism standard.
The suite can be used to measure along the following vector:
Compilation method: Consistent compiler options across all programs of a given language (the base metrics) and, optionally, compiler options tuned to each program (the peak metrics). See Q14, below, for more information.
SPEC OMP2012 is not intended to stress other computer components such as networking, the operating system, graphics, or the I/O system. Note that there are many other SPEC benchmarks, including benchmarks that specifically focus on graphics, distributed Java computing, webservers, and network file systems.
SPEC OMP2012 provides a comparative measure of parallel performance using OpenMP. If this matches with the type of workloads you are interested in, SPEC OMP2012 provides a good reference point.
Other advantages to using SPEC OMP2012 include:
As described above, the ideal benchmark for vendor or product selection would be your own workload on your own application. Please bear in mind that no standardized benchmark can provide a perfect model of the realities of your particular system and user community.
SPEC provides the following on the SPEC OMP2012 image:
Briefly, you need a Unix, Linux, Mac OS X, or Microsoft Windows system with compilers; 8GB of free disk space; and a minimum of 32GB of free memory - although more may be required, as described in system-requirements.html
Installation and use are covered in detail in the SPEC OMP2012 User Documentation. The basic steps are:
If you wish to generate results suitable for quoting in public, you will need to carefully study and adhere to the run rules.
OMPG2012 is based on compute-intensive applications provided as source code. OMPG2012 contains 14 benchmarks: 8 use Fortran, 5 use C, and 1 use C++. The benchmarks are:
|350.md||Fortran||Physics: Molecular Dynamics|
|351.bwaves||Fortran||Physics: Computational Fluid Dynamics (CFD)|
|357.bt331||Fortran||Physics: Computational Fluid Dynamics (CFD)|
|362.fma3d||Fortran||Mechanical Response Simulation|
|370.mgrid331||Fortran||Physics: Computational Fluid Dynamics (CFD)|
|371.applu331||Fortran||Physics: Computational Fluid Dynamics (CFD)|
|372.smithwa||C||Optimal Pattern Matching|
|376.kdtree||C++||Sorting and Searching|
Descriptions of the benchmarks, with reference to papers, web sites, and so forth, can be found in the individual benchmark descriptions (click the links above). Some of the benchmarks also provide additional details, such as documentation from the original program, in the nnn.benchmark/Docs directories in the SPEC benchmark tree.
The numbers used as part of the benchmark names provide an identifier to help distinguish programs from one another.
Many of the SPEC benchmarks have been derived from publicly available application programs. The individual benchmarks in this suite may be similar, but are NOT identical to benchmarks or programs with similar names which may be available from sources other than SPEC. In particular, SPEC has invested significant effort to improve portability and to minimize hardware dependencies, to avoid unfairly favoring one hardware platform over another. For this reason, the application programs in this distribution may perform differently from commercially available versions of the same application.
Therefore, it is not valid to compare SPEC OMP2012 benchmark results with anything other than other SPEC OMP2012 benchmark results.
After the benchmarks are run on the system under test (SUT), a ratio for each of them is calculated using the run time on the SUT and a SPEC-determined reference time. From these ratios, the following metrics are calculated:
OMPG2012 (for OpenMP compute intensive parallel performance comparisons):
Compute Performance metrics:
Energy Consumption metrics:
In all cases, a higher score means "better performance" on the given workload.
In order to provide comparisons across different computer hardware, SPEC provides the benchmarks as source code. Thus, in order to run the benchmarks, they must be compiled. There is agreement that the benchmarks should be compiled the way users compile programs. But how do users compile programs?
Some users might experiment with many different compilers and compiler flags to achieve the best performance, and may be willing to develop multi-step make processes and "training" workloads.
Other users might prefer the relative simplicity of using a single set of switches and a single-step make process.
In addition to the above, a wide range of other types of usage models could also be imagined, ranging in a continuum from -Odebug at the low end, to inserting directives and/or re-writing the source code at the high end. Which points on this continuum should SPEC OMP2012 allow?
SPEC recognizes that any point chosen from that continuum might seem arbitrary to those whose interests lie at a different point. Nevertheless, choices must be made.
For OMP2012, SPEC has chosen to allow two types of compilation:
The base metrics (e.g. SPECompG_base2012) are required for all reported results and have stricter guidelines for compilation. For example, the same flags must be used in the same order for all benchmarks of a given language. This is the point closer to those who might prefer a relatively simple build process.
The peak metrics (e.g. SPECompG_peak2012) are optional and have less strict requirements. For example, different compiler options may be used on each benchmark, and feedback-directed optimization is allowed. This point is closer to those who may be willing to invest more time and effort in development of build procedures.
Note that options allowed under the base metric rules are a subset of those allowed under the peak metric rules. A legal base result is also legal under the peak rules but a legal peak result is NOT necessarily legal under the base rules.
A full description of the distinctions and required guidelines can be found in the SPEC OMP2012 Run and Reporting Rules.
With OMP2012, SPEC is providing a way to measure the power consumed during the benchmark run.
The benchmark reports lists many other power measure data.
It depends on your needs. SPEC provides the benchmarks and results as tools for you to use. You need to determine how you use a computer or what your performance requirements are and then choose the appropriate SPEC benchmark or metrics.
Technology is always improving. As the technology improves, the benchmarks should improve as well. SPEC needed to address the following issues:
As of summer, 2012, many of the OMP2001 benchmarks are finishing in less than a minute on large parallel system. SPEC has attempted to address this with new benchmarks and data sets to have good scaling to 512 OpenMP threads while running in a non-trivial amount of time.
OpenMP new features:
As the OpenMP standard has changed, additional features have been added. OMP2012 attempts to include many of these features.
OMP2001 has been available for eleven years and much improvement in hardware and software has occurred during this time. Benchmarks need to evolve to keep pace with improvements.
OMP2012 includes the optional ability to measure power consumpution during the benchmark run.
SPEC will begin the process of retiring OMP2001. Three months after the announcement of OMP2012, SPEC will require all OMP2001 results submitted for publication on SPEC's web site to be accompanied by OMP2012 results. Six months after announcement, SPEC will stop accepting OMP2001 results for publication on its web site.
There is no formula for converting OMP2001 results to OMP2012 results and vice versa; they are different products. There probably will be some correlation between OMP2001 and OMP2012 results (i.e., machines with higher OMP2001 results often will have higher OMP2012 results), but there is no universal formula for all systems.
SPEC encourages SPEC licensees to publish OMP2012 numbers on older platforms to provide a historical perspective on performance.
In the process of selecting applications to use as benchmarks, SPEC considered the following criteria:
Although some of the benchmarks from OMP2001 are included in OMP2012, they all have been given different workloads and/or modified to use newer versions of the source code. Therefore, for example, results with the OMP2001 benchmark 312.swim_m may be strikingly different from results with the OMP2012 benchmark 363.swim.
Some benchmarks were not retained because it was not possible to create a longer-running or more robust workload. Others were left out because SPEC felt that they did not add significant performance information compared to the other benchmarks under consideration.
SPEC uses a reference machine to normalize the performance metrics used in the OMP2012 suites. Each benchmark is run and measured on this machine to establish a reference time for that benchmark. These times are then used in the SPEC calculations.
SPEC uses a historical Sun system, the "Sun Fire X4140" which was introduced in 2008, as the reference machine. The reference machine uses two quad-core 2.7 GHz AMD Opteron 2384 processors with 32GB of memory.
It takes about two days to do a rule-conforming run of the base metrics on the reference machine.
Note that when comparing any two systems measured with the OMP2012, their performance relative to each other would remain the same even if a different reference machine was used. This is a consequence of the mathematics involved in calculating the individual and overall (geometric mean) metrics.
This depends on the suite and the machine that is running the benchmarks. As mentioned above, the reference (historical) machine takes on the order of 2 days; contemporary machines might take less. Again, though, it depends on which metrics are run.
To generate rule-compliant results, an approved toolset must be used. If several attempts at using the SPEC-provided tools are not successful, you should contact SPEC for technical support. SPEC may be able to help you, but this is not always possible -- for example, if you are attempting to build the tools on a platform that is not available to SPEC.
If you just want to work with the benchmarks and do not care to generate publishable results, SPEC provides information about how to do so.
Results for measurements submitted to SPEC are available at http://www.spec.org/omp2012.
Yes, SPEC OMP2012 results can be freely published if all the run and reporting rules have been followed. The OMP2012 license agreement binds every purchaser of the suite to the run and reporting rules if results are quoted in public. A full disclosure of the details of a performance measurement must be provided on request.
SPEC strongly encourages that results be submitted for publication on SPEC's web site, since it ensures a peer review process and uniform presentation of all results.
The run and reporting rules for research and and academic contexts recognize that it may not be practical to comply with the full set of rules in some contexts. It is always required, however, that non-compliant results must be clearly distinguished from rule-compliant results.
SPEC can be contacted in several ways. For general information, including other means of contacting SPEC, please see SPEC's Web Site at:
General questions can be emailed to: firstname.lastname@example.org
OMP2012 Technical Support Questions can be sent to: email@example.com
If you haven't bought OMP2012, it is hoped that you will consider doing so. If you are ready to get started using the suite, then you should pick a system that meets the requirements as described in
and install the suite, following the instructions in
Questions and answers were originally prepared by Kaivalya Dixit of IBM, Jeff Reilly of Intel Corp, and John Henning of Oracle. Dixit was the long-time President of SPEC, Reilly is Chair of the SPEC CPU Subcommittee, and Henning is Vice-Chair/Secretary of the SPEC CPU Subcommittee.
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