NBench

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NBench, short for Native mode Benchmark and later known as BYTEmark, is a synthetic computing benchmark program developed in the mid-1990s by the now defunct BYTE magazine intended to measure a computer's CPU, FPU, and Memory System speed.

In computing, a benchmark is the act of running a computer program, a set of programs, or other operations, in order to assess the relative performance of an object, normally by running a number of standard tests and trials against it. The term benchmark is also commonly utilized for the purposes of elaborately designed benchmarking programs themselves.

<i>Byte</i> (magazine) American computing magazine

Byte was an American microcomputer magazine, influential in the late 1970s and throughout the 1980s because of its wide-ranging editorial coverage. Whereas many magazines were dedicated to specific systems or the home or business users' perspective, Byte covered developments in the entire field of "small computers and software," and sometimes other computing fields such as supercomputers and high-reliability computing. Coverage was in-depth with much technical detail, rather than user-oriented.

Floating-point unit part of a computer system specially designed to carry out operations on floating point numbers

A floating-point unit is a part of a computer system specially designed to carry out operations on floating point numbers. Typical operations are addition, subtraction, multiplication, division, square root, and bitshifting. Some systems can also perform various transcendental functions such as exponential or trigonometric calculations, though in most modern processors these are done with software library routines.

Contents

History

NBench is essentially release 2 of BYTE Magazine's BYTEmark benchmark program (previously known as BYTE's Native Mode Benchmarks), published about 1995, which was just a few years before the magazine ceased publication. NBench is written in C, and was initially focused on PCs running the Microsoft Windows operating system. Independently of BYTE, in 1996 NBench was ported to Linux and other flavors of Unix by Uwe F. Mayer. [1] More recently Ludovic Drolez prepared an NBench App for the Android mobile device operating system. [2] NBench should not be confused with the similarly named but unrelated AMD N-Bench. [3]

C (programming language) general-purpose programming language

C is a general-purpose, imperative computer programming language, supporting structured programming, lexical variable scope and recursion, while a static type system prevents many unintended operations. By design, C provides constructs that map efficiently to typical machine instructions, and it has therefore found lasting use in applications that were previously coded in assembly language. Such applications include operating systems, as well as various application software for computers ranging from supercomputers to embedded systems.

Linux Family of free and open-source software operating systems based on the Linux kernel

Linux is a family of free and open-source software operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991 by Linus Torvalds. Linux is typically packaged in a Linux distribution.

Unix family of computer operating systems that derive from the original AT&T Unix

Unix is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, development starting in the 1970s at the Bell Labs research center by Ken Thompson, Dennis Ritchie, and others.

Design

The NBench algorithm suite consists of ten different tasks: [4]

A run of the benchmark suite consists essentially of two phases for each of the tests. First, a calibration loop is run to determine the size of the problem the system can handle in a reasonable time, in order to adapt to the ever-faster computer hardware available. Second, the actual test is run repeatedly several times to obtain a statistically meaningful result.

Originally, NBench and BYTEmark produced two overall index figures: Integer index and Floating-point index. The Integer index is the geometric mean of those tests that involve only integer processing—numeric sort, string sort, bitfield, emulated floating-point, assignment, Huffman, and IDEA—while the Floating-point index is the geometric mean of those tests that require the floating-point coprocessor—Fourier, neural net, and LU decomposition. The index figures where relative scores to get a general feel for the performance of the machine under test as compared to a baseline system based on a 90 MHz Pentium Intel CPU.

The Linux/Unix port has a second baseline machine, it is an AMD K6/233 with 32 MB RAM and 512 KB L2-cache running Linux 2.0.32 and using GNU gcc version 2.7.2.3 and libc-5.4.38. The original integer index was split into an integer-operation and a memory-operation index, as suggested by Andrew D. Balsa, reflecting the realization that memory management is important in CPU design. The original tests have been left alone, however, the geometric mean of the tests numeric sort, floating-point emulation, IDEA, and Huffman now constitutes the integer-arithmetic focused benchmark index, while the geometric mean of the tests string sort, bitfield, and assignment makes up the new memory index. The floating point index has been left alone, it is still the geometric mean of fourier, neural net, and LU decomposition.

Use

The benchmark suite has seen consistent use since the mid-1990s by the personal computing community, on PCs and other devices running various flavors of UNIX including Linux [5] [6] or BSD, [7] or running Windows (usually in combination with Cygwin), [8] and on also on Macs (it is in particular available as a Darwin port [9] ). A results page from runs on many different hardware configurations, from high-powered multi-CPU servers down to low-powered network switches, is maintained by the original porter. [8]

Cygwin Unix subsystem for Windows machines

Cygwin is a POSIX-compatible environment that runs natively on Microsoft Windows. Its goal is to allow programs of Unix-like systems to be recompiled and run natively on Windows with minimal source code modifications by providing them with the same underlying POSIX API they would expect in those systems.

Darwin is an open-source Unix-like operating system first released by Apple Inc. in 2000. It is composed of code developed by Apple, as well as code derived from NeXTSTEP, BSD, Mach, and other free software projects.

Shortcomings

Using NBench as a benchmark has pitfalls:

See also

The Whetstone benchmark is a synthetic benchmark for evaluating the performance of computers. It was first written in Algol 60 in 1972 at TSU. It was derived from statistics on program behaviour gathered on the KDF9 computer at NPL National Physical Laboratory in the United Kingdom, using a modified version of its Whetstone ALGOL 60 compiler. The workload on the machine was represented as a set of frequencies of execution of the 124 instructions of the Whetstone Code. The Whetstone Compiler was built at the Atomic Power Division of the English Electric Company in Whetstone, Leicestershire, England, hence its name. Dr. B.A. Wichman at NPL produced a set of 42 simple ALGOL 60 statements, which in a suitable combination matched the execution statistics.

Dhrystone is a synthetic computing benchmark program developed in 1984 by Reinhold P. Weicker intended to be representative of system (integer) programming. The Dhrystone grew to become representative of general processor (CPU) performance. The name "Dhrystone" is a pun on a different benchmark algorithm called Whetstone.

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DEC Alpha 64-bit RISC microprocessor

Alpha, originally known as Alpha AXP, is a 64-bit reduced instruction set computing (RISC) instruction set architecture (ISA) developed by Digital Equipment Corporation (DEC), designed to replace their 32-bit VAX complex instruction set computer (CISC) ISA. Alpha was implemented in microprocessors originally developed and fabricated by DEC. These microprocessors were most prominently used in a variety of DEC workstations and servers, which eventually formed the basis for almost all of their mid-to-upper-scale lineup. Several third-party vendors also produced Alpha systems, including PC form factor motherboards.

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Endianness is the sequential order in which bytes are arranged into larger numerical values when stored in memory or when transmitted over digital links. Endianness is of interest in computer science because two conflicting and incompatible formats are in common use: words may be represented in big-endian or little-endian format, depending on whether bits or bytes or other components are ordered from the big end or the little end.

In computing, Streaming SIMD Extensions (SSE) is a single instruction, multiple data (SIMD) instruction set extension to the x86 architecture, designed by Intel and introduced in 1999 in their Pentium III series of Central processing units (CPUs) shortly after the appearance of Advanced Micro Devices (AMD's) 3DNow!. SSE contains 70 new instructions, most of which work on single precision floating point data. SIMD instructions can greatly increase performance when the exact same operations are to be performed on multiple data objects. Typical applications are digital signal processing and graphics processing.

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References

  1. ↑ Mayer, Uwe F. "Linux/Unix NBench" . Retrieved 2018-06-09.
  2. ↑ Drolez, Ludovic. "Android NBench" . Retrieved 2017-06-26.
  3. ↑ Advanced Micro Devices, Inc. "AMD N-Bench" . Retrieved 2011-02-07.
  4. ↑ BYTE Magazine. "Original NBench documentation (archived snapshot)" (PDF). Retrieved 2011-01-11.
  5. ↑ FreshMeat. "Project NBench" . Retrieved 2011-02-07.
  6. ↑ Novel Shareware. "NBench" . Retrieved 2011-02-10.
  7. ↑ BSD FTP Site. "NBench" . Retrieved 2011-02-10.
  8. 1 2 Mayer, Uwe F. "NBench Results" . Retrieved 2011-02-07.
  9. ↑ Darwin Ports. "NBench" . Retrieved 2011-02-07.
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