Instructions per second

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Instructions per second (IPS) is a measure of a computer's processor speed. Many reported IPS values have represented "peak" execution rates on artificial instruction sequences with few branches, whereas realistic workloads typically lead to significantly lower IPS values. The performance of the memory hierarchy also greatly affects processor performance, an issue barely considered in MIPS calculations. Because of these problems, researchers created standardized tests such as SPECint to attempt to measure the real effective performance in commonly used applications, and raw IPS has fallen into disuse.

The term is commonly used in association with a numeric value such as thousand instructions per second (kIPS), million instructions per second (MIPS), or Million Operations per Second (MOPS).



[edit] Thousand instructions per second

Before standard benchmarks were available, average speed rating of computers was based on calculations for a mix of instructions with the results given in kilo Instructions Per Second (kIPS). The most famous was the Gibson Mix, produced by Jack Clark Gibson of IBM for scientific applications. Other ratings were also produced for commercial applications. Computer Speeds From Instruction Mixes pre-1960 to 1971 has results for around 175 computers, providing scientific and commercial ratings. For IBM, the earliest Gibson Mix calculations shown are the 1954 IBM 650 at 0.06 kIPS and 1956 IBM 705 at 0.5 kIPS. The results are mainly for IBM and others known as the BUNCH - Burroughs, Univac, NCR, CDC and Honeywell.

A thousand instructions per second (kIPS) is rarely used, as most current microprocessors can execute a least a billion instructions per second. The thousand means 1000, not 1024.

kIPS is also a common joke name for 16 bit microprocessor designs developed in undergraduate computer engineering courses that use the text Computer Organization and Design by Patterson and Hennessy (ISBN 1-55860-428-6), which explains computer architecture concepts in terms of the MIPS architecture. Such architectures tend to be scaled down versions of the MIPS R2000 architecture.

[edit] Million instructions per second

Comparison of processors speeds requires thorough analysis, as the speed of a given CPU is dependent upon many factors, such as the type of instructions being executed, the execution order and the presence of branch instructions (problematic in CPU pipelines). CPU instruction rates are different from clock frequencies, usually reported in Hz, as each instruction may require several clock cycles to complete or may be capable of executing multiple independent instructions at once. Additionally, the number of cycles required for instructions to complete is dependent upon the instruction being executed. MIPS are difficult to compare between CPU architectures. This and other limitations of the unit lead many computer engineers to define MIPS as Meaningless Indicator of Processor Speed.[1]

In the late 1970s, minicomputer performance was compared using VAX MIPS, where computers were measured on a task and their performance rated against the VAX 11/780 that was marketed as a 1 MIPS machine. (The measure was also known as the VAX Unit of Performance or VUP. Though orthographically incorrect, the s in VUPs is sometimes written in upper case.) This was chosen because the 11/780 was roughly equivalent in performance to an IBM System/370 model 158-3, which was commonly accepted in the computing industry as running at 1 MIPS.

Many of the minicomputer performance claims were based on the Fortran version of the Whetstone benchmark. This produces an artificial speed rating in Millions of Whetstone Instructions Per Second (MWIPS). The VAX 11/780 with FPA (1977) is shown as having a rating of 1.02 MWIPS.

Effective MIPS speeds are highly dependent on the programming language used.The Whetstone Report has a table showing MWIPS speeds of PCs via early interpreters and compilers up to modern languages. The first compiler was for BASIC (1982) when a 4.8 MHz 8088/87 CPU obtained 0.01 MWIPS. Results on a 2.4 GHz Core 2 Duo (1 CPU 2007) vary from 9.7 MWIPS using BASIC Interpreter, 59 MWIPS via BASIC Compiler, 347 MWIPS using 1987 Fortran, 1,534 MWIPS through HTML/Java to 2,403 MWIPS using a modern C/C++ compiler.

For the most early 8-bit and 16-bit microprocessors the performance was recognized in thousand instructions per second (kIPS), which equals 0.001 MIPS. The first general purpose microprocessor, the Intel i8080, ran at 0.64 MIPS. The Intel i8086 microprocessor, the first 16-bit microprocessor in the line of processors made by Intel and used in IBM PCs, ran at 0.8 MIPS. Early 32-bit PCs (386) ran at about 3 MIPS.

zMIPS refers to the MIPS measure used internally by IBM to rate its mainframe servers (zSeries, IBM System z9, and IBM System z10).

[edit] Timeline of instructions per second

Processor↓ IPS↓ Instructions / clock cycle↓ Year↓ Source↓
Intel 4004 92 kIPS at 740 kHz 0.1 1971 [2]
IBM System/370 model 158-3 1 MIPS 1.0 1972
Intel 8080 500 kIPS at 2 MHz 0.3 1974
MOS Technology 6502 500 kIPS at 1 MHz 0.5 1975
VAX-11/780 500 kIPS 0.5 1977
Motorola 68000 1 MIPS at 8 MHz 0.1 1979
Intel 286 2.66 MIPS at 12.5 MHz 0.2 1982 [3]
ARM2 4 MIPS at 8 MHz 0.5 1986
Motorola 68020 4 MIPS at 20 MHz 0.2 1984
Motorola 68030 11 MIPS at 33 MHz 0.3 1987
Intel 386DX 11.4 MIPS at 33 MHz 0.3 1985
ARM 7500FE 35.9 MIPS at 40 MHz 0.9 1996
Motorola 68040 44 MIPS at 40 MHz 1.1 1990
Intel 486DX 54 MIPS at 66 MHz 0.8 1992
Zilog eZ80 80 MIPS at 50 MHz 1.6 1999 [4]
Motorola 68060 88 MIPS at 66 MHz 1.33 1994
ETRAX 100LX 100 MIPS at 100 MHz n/a n/a [5] Axis Communications
ETRAX 200FS 200 MIPS at 200 MHz n/a n/a [5] Axis Communications
DEC Alpha 21064 EV4 300 MIPS at 150 MHz 2.7 1992 [6]
Intel Pentium Pro 541 MIPS at 200 MHz 2.7 1996 [7]
PowerPC 750 525 MIPS at 233 MHz 2.3 1997
Freescale MPC8272 760 MIPS at 400 MHz 1.9 2000 [8] Integrated Communications Processors
Intel Pentium III 1,354 MIPS at 500 MHz 2.7 1999
AMD Athlon 3,561 MIPS at 1.2 GHz 3.0 2000
AMD Athlon XP 2400+ 5,935 MIPS at 2.0 GHz 3.0 2002
Pentium 4 Extreme Edition 9,726 MIPS at 3.2 GHz 3.0 2003
ARM Cortex A8 2,000 MIPS at 1.0 GHz 2.0 2005 [9]
AMD Athlon FX-57 12,000 MIPS at 2.8 GHz 4.3 2005
AMD Athlon 64 3800+ X2 (Dual Core) 14,564 MIPS at 2.0 GHz 7.3 2005 [10]
Xbox360 IBM "Xenon" Triple Core 19,200 MIPS at 3.2 GHz 6.0 2005
PS3 Cell BE (PPE only) 10,240 MIPS at 3.2 GHz 3.2 2006
AMD Athlon FX-60 (Dual Core) 18,938 MIPS at 2.6 GHz 7.3 2006 [10]
Intel Core 2 Extreme X6800 27,079 MIPS at 2.93 GHz 9.2 2006 [10]
Intel Core 2 Extreme QX6700 49,161 MIPS at 2.66 GHz 18.5 2006 [11]
P.A. Semi PA6T-1682M 8,800 MIPS at 2.0 GHz 4.4 2007 [12]
Intel Core 2 Extreme QX9770 59,455 MIPS at 3.2 GHz 18.6 2008 [13]
Intel Core i7 Extreme 965EE 76,383 MIPS at 3.2 GHz 23.9 2008 [14]
AMD Phenom II X4 940 Black Edition 42,820 MIPS at 3.0 GHz 14.3 2009 [15]
AMD Phenom II X6 1090T 68,200 MIPS at 3.2 GHz 21.3 2010 [16]
Intel Core i7 Extreme Edition i980EE 147,600 MIPS at 3.3 GHz 44.7 2010 [17]
IBM 5.2-GHz z196 (to be released 9/2010) 520,833 MIPS at 5.6 GHz n/a 2010 [18]

[edit] Historic Data

[edit] See also

[edit] References

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