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SPECfp

SPECfp is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand SPECfp rather than just read about it. In short: SPECfp is a computer benchmark designed to test the floating-point performance of a computer. It is managed by the Standard Performance Evaluation Corporation.

Key takeaways

  • SPECfp belongs to computer science; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect SPECfp to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of SPECfp from memory before moving on to harder problems.

Reference excerpt

SPECfp is a computer benchmark designed to test the floating-point performance of a computer. It is managed by the Standard Performance Evaluation Corporation. SPECfp is the floating-point performance testing component of the SPEC CPU testing suit. The first standard SPECfp was released in 1989 as SPECfp89. Later it was replaced by SPECfp92, then SPECfp95, then SPECfp2000, then SPECfp2006, and finally SPECfp2017.

Background SPEC CPU2017 is a suite of benchmark applications designed to test the CPU performance. The suite is composed of two sets of tests. The first being CINT (aka SPECint) which is for evaluating the CPU performance in integer operations. The second set is CFP (aka SPECfp) which is for evaluating the CPU floating-point operations performance. The benchmark applications are programs that perform a strict set of operation that simulate real time situations, such as physical simulations, 3D graphics, and image processing. These applications are written in different programming languages, C, C++ and Fortran. Many SPECfp benchmark applications are derived from applications that are freely available to the public and each application is assigned a weight based on its importance. To compute the SPECfp score, benchmark applications run on a reference machine and the time each application requires for completion is recorded as the reference time. When evaluating the performance of another machine, the benchmark application is run on that system and the time the application requires for completion is recorded. Then the ratio between the recorded time and the reference time is computed. The geometric mean of all the benchmark suite application ratios is then computed as the SPECfp score. For example, 126.gcc application takes 1280 seconds to complete on the AlphaStation 200 4/100, while it takes 1700 seconds on the reference machine. So, the ratio is: 1700/1280 = 1.328, which implies that AlphaStation 200 4/100 is 32.8% faster than the reference machine in running the 126.gcc.

SPECfp2017 The SPECfp2017 test is organized in 2 suites: SPECrate 2017 Floating Point and SPECspeed 2017 Floating Point containing in total 23 benchmark programs, designed to evaluate the floating-point operations performance of a given system. The suite was released on June 2, 2017 replacing SPECfp2006 as of January 2018.

SPECfp2006 The SPECfp2006 test suite contains 17 benchmark programs, designed to evaluate the floating-point operations performance of a given system. Three of these programs are written in C, four are written in C++, six are written in Fortran, and four are written in both C and Fortran. The suite was released on August 24, 2006 replacing SPECfp2000 as of February 2007.

Benchmarks The benchmark programs are:

SPECfp2000 The SPECfp2000 test suite contains 14 benchmark programs, designed to evaluate the floating-point operations performance of a given system. Four of these programs are written in C, six are written in Fortran 77, and four are written in Fortran 90. The suite was released on December 30, 1999 replacing SEPCfp95 as of July 2000. This suite is currently retired.

Benchmarks The benchmark programs are:

SPECfp95 The SPECfp95 test suite contains 10 benchmark programs, designed to evaluate the floating-point operations performance of a given system. The suite was released in March 1995 replacing SEPCfp92 as of September 1995. This suite is currently retired.

Benchmarks The benchmark programs are:

SPECfp92 The SPECfp92 test suite contains 14 benchmark programs, designed to evaluate the floating-point operations performance of a given system. Twelve of these programs are written in Fortran, and two are written in C. The suite was released in 1995 replacing SPECfp89. With the release of this suite, the Baseline rule was introduced; in which vendors are no longer allowed to optimize the compilation of the code without reporting it. This suite is currently retired.

Benchmarks The benchmark programs are:

See also NBench

References

External links [1] (Floating Point Component of SPEC CPU2006) [2] (Floating Point Component of SPEC CPU2000) [3] (Floating Point Component of SPEC CPU95) [4] (Floating Point Component of SPEC CPU92)

Worked examples

Example 1 — a first encounter with SPECfp

Start with the simplest possible case. Write down what SPECfp claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to SPECfp before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about SPECfp ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of SPECfp

In research
SPECfp appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses SPECfp in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
SPECfp is common in secondary-school and first-year university syllabi. It links to neighbouring topics Benchmarks (computing), so understanding it makes those chapters shorter.
In everyday life
Look for SPECfp outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study SPECfp in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what SPECfp means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain SPECfp out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is SPECfp in simple terms?

SPECfp is a computer benchmark designed to test the floating-point performance of a computer. It is managed by the Standard Performance Evaluation Corporation.

Why does SPECfp matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study SPECfp?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on SPECfp.

Tags

  • Benchmarks (computing)

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