Computer Performance Issues and Microprocessors

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Questions and Answers

What is a significant feature of modern microprocessor technology that enhances performance?

Superscalar architecture (correct)

Decreased demand for computing power

Single instruction processing

Increased physical size of processors

Which of the following applications would benefit most from powerful microprocessors?

Spreadsheet calculations

Basic word processing

Image processing (correct)

Simple note-taking

What do contemporary processors use to improve efficiency by predicting future processing needs?

Sequential processing

Branch prediction (correct)

Multiprocessing

Branch judgment

In what way have businesses adapted their computing architecture in recent years?

By increasing reliance on powerful servers Signup and view all the answers

Which technique allows a processor to handle multiple stages of instruction processing at once?

Pipelining Signup and view all the answers

What has contributed to the dramatic decrease in the cost of computer systems?

The rise of microprocessor-based systems Signup and view all the answers

What is the advantage of using cloud service providers for businesses?

High-volume, high-transaction capabilities Signup and view all the answers

What is the primary purpose of the SPEC benchmark suites?

To evaluate and compare computer system performance Signup and view all the answers

Which programming languages are used in the CPU2006 benchmark suite?

C, C++, and Fortran Signup and view all the answers

How many floating point programs are included in the CPU2006 benchmark suite?

17 Signup and view all the answers

What aspect of computer performance does the CPU2006 benchmark primarily measure?

Processor intensive applications Signup and view all the answers

What is a characteristic of the 401.bzip2 benchmark in the CPU2006 suite?

It primarily performs general-purpose data compression Signup and view all the answers

Which of the following components is NOT typically part of performance factors in system architecture?

User interface design Signup and view all the answers

Which formula is NOT used to calculate the mean value of a set of data points?

Median Signup and view all the answers

In benchmarking, what is primarily being compared across systems?

Execution time Signup and view all the answers

Which factor is directly related to the capability of executing instructions in a system?

Instruction set architecture Signup and view all the answers

Which of the following best describes 'compiler technology' in system performance?

It translates high-level code into machine code. Signup and view all the answers

What does the term 'system clock' refer to in the context of computer architecture?

The frequency at which the processor performs operations Signup and view all the answers

What is typically NOT a part of cache and memory hierarchy?

Hard disk drive Signup and view all the answers

Which aspect of system performance primarily depends on 'processor implementation'?

Instruction execution speed Signup and view all the answers

What aspect of performance measurement is primarily related to variance in execution time?

Benchmarking Signup and view all the answers

Which of the following is NOT a performance attribute in the context of computing systems?

Aesthetic appeal Signup and view all the answers

What is one benefit of shrinking logic gate size in processors?

More gates can be packed tightly, increasing clock rate Signup and view all the answers

Which of the following describes a significant downside of increased clock speed?

Higher power density and heat dissipation Signup and view all the answers

What factor limits the speed at which electrons flow within a processor?

Resistance and capacitance of metal wires Signup and view all the answers

Which improvement in a processor is indicated by increasing the size and speed of caches?

Significantly reduced cache access times Signup and view all the answers

What changes in processor organization can enhance instruction execution speed?

Implementing parallelism Signup and view all the answers

What happens to memory speeds in relation to processor speeds?

Memory speeds can lag behind processor speeds Signup and view all the answers

What is the primary benefit of using multiple processors on the same chip?

It increases performance without increasing the clock rate. Signup and view all the answers

Which of the following best explains why power density increases in modern processors?

Greater logic density and clock speed Signup and view all the answers

What characteristic of wire interconnects contributes to increased RC delay?

Increased resistance and capacitance with component size reduction Signup and view all the answers

Why is the strategy favoring two simpler processors over one complex processor?

They allow for better multitasking and efficiency. Signup and view all the answers

Why is there a need for improvements in chip architecture?

To keep effective instruction execution speed increasing Signup and view all the answers

What justifies the inclusion of larger caches when using two processors?

The need for faster access to frequently used data. Signup and view all the answers

What development followed as caches became larger in multicore processors?

The development of additional levels of cache. Signup and view all the answers

What is a potential advantage of having three levels of cache on a chip?

It minimizes data access times for the processors. Signup and view all the answers

What is a disadvantage of relying solely on a single complex processor?

It can lead to overloading that processor. Signup and view all the answers

How do multiple processors influence the design of the chip's architecture?

They allow for simpler processor designs. Signup and view all the answers

What is the implication of integrating larger caches with multicore processors?

Larger caches can significantly improve processing efficiency. Signup and view all the answers

Which configuration may be less advantageous in terms of performance perception?

One complex processor with a smaller cache. Signup and view all the answers

How does the innovation of multicore processors affect software design?

Software must be more complex to take advantage of multicore architecture. Signup and view all the answers

Study Notes

Lecture 2: Performance Issues

The cost of computer systems continues to decrease dramatically, while performance and capacity increase equally.
Today's laptops have computing power similar to an IBM mainframe 10-15 years ago.
Processors (microprocessors) often have inexpensive cost, potentially disposable.
Desktop applications requiring significant microprocessor-based system power include: image processing, 3D rendering, speech recognition, video conferencing, multimedia authoring, voice and video annotation of files, and simulation modeling.
Businesses rely on powerful servers for transaction and database processing and support massive client/server networks that replace large mainframe systems.
Cloud service providers utilize massive high-performance server banks to support high-volume, high-transaction-rate applications.

Microprocessor Speed

Contemporary processors include techniques like: pipelining, branch prediction, superscalar execution, and data flow analysis, and speculative execution.
Pipelining moves data/instructions through stages simultaneously, improving workflow.
Branch prediction anticipates instruction sequences, streamlining processing.
Superscalar execution allows multiple instructions per clock cycle using parallel pipelines.
Data flow analysis prioritizes instructions based on dependencies for optimized scheduling.
Speculative execution temporarily anticipates instructions ahead of execution, maximizing engine use.

Performance Balance

Adjusting organization and architecture to compensate for varying component capabilities is key.
Architectural examples include: increasing the number of bits retrieved simultaneously by widening data paths, reducing memory access frequency by adding complex caches between processor and main memory, and improving DRAM interface efficiency through schemes like on-chip caching.
Increasing interconnect bandwidth (communication between processors and memory) helps with faster buses and a tiered bus structure.

I/O Device Data Rates

A chart showing data rates (bits per second) for various input/output (I/O) devices.
Examples include Ethernet modem, graphics displays, Wi-Fi modems, hard drives, optical drives, laser printers, scanners, mice, and keyboards.

Improvements in Chip Organization and Architecture

Increasing processor speed, fundamentally, arises from shrinking logic gate sizes and packing more tightly (more gates), increasing clock rate.
Signal propagation times reduce as circuit density increases.
Increasing and speeding up on-chip caches improve performance.
Revising processor organization and architecture leads to improved instruction execution speed and parallelization.

Problems with Clock Speed and Logic Density

Power density increases directly with logic and clock speed (more transistors use more power).
Heat dissipation is crucial.
Speed (electron flow) is limited by factors like resistance and wire capacitance, increasing delays as components/wires shrink.
As components shrink, interconnect resistance increases while capacitance also increases, making speed enhancement harder.
Memory latency (memory speed) typically lags behind processor speed increases and limits overall performance.

Processor Trends

A graph demonstrating the increasing trend of transistors (thousands), frequency (MHz), power (watts), and cores over time starting roughly around 1970 – showing exponential growth in transistors despite the limitations of processing power (power consumed).

Multicore

Utilizing multiple processors on a single chip improves performance without increasing clock speed.
Simplified processors are often advantageous over more complex processors.
Larger caches are often used in dual processor setups to optimize processing efficiency.
Multicore processors are more efficient in utilizing available cache resources, which are crucial for performance optimization.

Many Integrated Core (MIC) Graphics Processing Unit (GPU)

A leap in performance resulting from advanced software in dealing with numerous cores.
Homogeneous processors on a single chip are advantageous.
GPU optimized cores are built for high-parallel operations, especially for graphics data.
Typical use in plug-in graphics cards, encoding and rendering two- and three-dimensional graphics, as well as video processing.

Amdahl's Law

A fundamental calculation related to potential speedup when employing multiple processors in programs.
It highlights challenges in multi-core machine development.
Software needs adaptations for highly parallel environments to maximize parallel processing power.
It provides a generalized technique to evaluate and design computer system improvements.

Little's Law

A straightforward formula applicable to systems in a stable state that exhibit no loss/leakage of elements.
Applicable to queuing systems, demonstrating a relationship between item arrival rates and average wait times.
It has limited assumptions to make it generally applicable.

Calculating the Mean

Benchmarks compare systems by determining the average value of execution times using various (arithmetic, geometric, harmonic) mean calculations.
These common means are needed to assess benchmarks when comparing systems' performance.

Benchmark Principles

A benchmark program should meet important characteristics.
It should be written in high-level languages for platform portability.
It should be representative of typical programming uses to provide fair comparisons and demonstrate typical performance, such as in systems programming, numerical computing, or commercial programming.
It should be amenable to easy measurement.
It should have a broad distribution across platforms for greater applicability.

System Performance Evaluation Corporation (SPEC)

SPEC is a benchmark suite consisting of various programs, commonly used to test computer performance in specific application areas.
It represents a collection of industry-standard suites aimed at assessing system performance for benchmarking purposes and evaluating computer systems for comparative analysis and research purposes.

SPEC CPU2006

A well-known benchmarking suite used as a standard test for measuring processor performance in applications that spend most of their time computing (rather than input/output).
Consists of (17+12 programs) floating-point and integer programs written in C, C++, and Fortran.

Terms Used in SPEC Documentation

Benchmark, system under test, reference machine, and base metric are terms critical to the methodology and interpretation of SPEC benchmarks.

SPEC Evaluation Flowchart

This flowchart outlines the process used to evaluate computer system performance using the SPEC methodology.

SPEC CINT2006 Results

A table presenting SPEC CINT2006 benchmark results (execution times) on two different computing platforms.

SPEC CPU2006 Floating-Point Benchmarks

Further benchmark results for various floating-point applications.

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Description

This quiz focuses on performance issues related to modern computer systems and microprocessors. It covers advancements in computing power, applications relying on high-performance systems, and techniques that improve processor efficiency, such as pipelining and branch prediction. Test your knowledge on how these concepts apply to contemporary computing environments.