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).

Contents 1 Thousand instructions per second 2 Million instructions per second 3 Timeline of instructions per second 4 Historic Data 5 See also 6 References

[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

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Processor	IPS	Instructions / clock cycle	Year	Source
Intel 4004	00000010 92 kIPS at 740 kHz	001 0.1	1971	[2]
IBM System/370 model 158-3	0000010 1 MIPS	01 1.0	1972
Intel 8080	0000005 500 kIPS at 2 MHz	00250 0.3	1974
MOS Technology 6502	0000005 500 kIPS at 1 MHz	005 0.5	1975
VAX-11/780	0000005 500 kIPS	005 0.5	1977
Motorola 68000	0000010 1 MIPS at 8 MHz	00125 0.1	1979
Intel 286	0000026 2.66 MIPS at 12.5 MHz	00220 0.2	1982	[3]
ARM2	0000040 4 MIPS at 8 MHz	00500 0.5	1986
Motorola 68020	0000040 4 MIPS at 20 MHz	00200 0.2	1984
Motorola 68030	0000110 11 MIPS at 33 MHz	00330 0.3	1987
Intel 386DX	0000114 11.4 MIPS at 33 MHz	00340 0.3	1985
ARM 7500FE	0000359 35.9 MIPS at 40 MHz	00897 0.9	1996
Motorola 68040	0000440 44 MIPS at 40 MHz	01100 1.1	1990
Intel 486DX	0000540 54 MIPS at 66 MHz	00818 0.8	1992
Zilog eZ80	0000800 80 MIPS at 50 MHz	01600 1.6	1999	[4]
Motorola 68060	0000880 88 MIPS at 66 MHz	01330 1.33	1994
ETRAX 100LX	0001000 100 MIPS at 100 MHz	00000 n/a	n/a	[5] Axis Communications
ETRAX 200FS	0002000 200 MIPS at 200 MHz	00000 n/a	n/a	[5] Axis Communications
DEC Alpha 21064 EV4	0003000 300 MIPS at 150 MHz	02705 2.7	1992	[6]
Intel Pentium Pro	0005410 541 MIPS at 200 MHz	02705 2.7	1996	[7]
PowerPC 750	0005250 525 MIPS at 233 MHz	02253 2.3	1997
Freescale MPC8272	0007600 760 MIPS at 400 MHz	01900 1.9	2000	[8] Integrated Communications Processors
Intel Pentium III	0013540 1,354 MIPS at 500 MHz	02708 2.7	1999
AMD Athlon	0035610 3,561 MIPS at 1.2 GHz	02967 3.0	2000
AMD Athlon XP 2400+	0059350 5,935 MIPS at 2.0 GHz	02967 3.0	2002
Pentium 4 Extreme Edition	0097260 9,726 MIPS at 3.2 GHz	03039 3.0	2003
ARM Cortex A8	0020000 2,000 MIPS at 1.0 GHz	02000 2.0	2005	[9]
AMD Athlon FX-57	0120000 12,000 MIPS at 2.8 GHz	04285 4.3	2005
AMD Athlon 64 3800+ X2 (Dual Core)	0145640 14,564 MIPS at 2.0 GHz	07282 7.3	2005	[10]
Xbox360 IBM "Xenon" Triple Core	0192000 19,200 MIPS at 3.2 GHz	060 6.0	2005
PS3 Cell BE (PPE only)	010240 10,240 MIPS at 3.2 GHz	032000 3.2	2006
AMD Athlon FX-60 (Dual Core)	0189380 18,938 MIPS at 2.6 GHz	07283 7.3	2006	[10]
Intel Core 2 Extreme X6800	0270790 27,079 MIPS at 2.93 GHz	09242 9.2	2006	[10]
Intel Core 2 Extreme QX6700	0491610 49,161 MIPS at 2.66 GHz	18481 18.5	2006	[11]
P.A. Semi PA6T-1682M	0088000 8,800 MIPS at 2.0 GHz	04400 4.4	2007	[12]
Intel Core 2 Extreme QX9770	0594550 59,455 MIPS at 3.2 GHz	18580 18.6	2008	[13]
Intel Core i7 Extreme 965EE	0763830 76,383 MIPS at 3.2 GHz	23860 23.9	2008	[14]
AMD Phenom II X4 940 Black Edition	042820 42,820 MIPS at 3.0 GHz	14273 14.3	2009	[15]
AMD Phenom II X6 1090T	068200 68,200 MIPS at 3.2 GHz	21313 21.3	2010	[16]
Intel Core i7 Extreme Edition i980EE	147600 147,600 MIPS at 3.3 GHz	44727 44.7	2010	[17]

[edit] Historic Data

• Computer Speeds From Instruction Mixes pre-1960 to 1971 (kIPS 175 systems)
• Computer Speed Claims 1980 to 1996 (MIPS >2000 systems)
• PC CPU Performance Comparisons %MIPS/MHz

[edit] See also

• FLOPS
• benchmark (computing)
• million service units (MSU)
• Peak MIPS
• Relative MIPS
• Dhrystone MIPS (DMIPS)

[edit] References