CSCI 402: Computer Architectures. Computer Abstractions and Technology. Recall. What is computer architecture

Transcription

1 CSCI 402: Computer Architectures Computer Abstractions and Technology Fengguang Song Department of Computer & Information Science IUPUI Recall What is computer architecture An art A combination of science and art Creativity can increase performance Top500 Supercomputer List Fast computer revolution and four paradigms 4 classes of computers 1

2 Notations Used in Textbook They are different! Note: we will try to follow these notations in this course Today What is the PostPC era Eight Great Ideas used in computer architecture What is below our program What hardware is inside the box Trend of CPU and memory technologies 4 2

3 The PostPC Era n Personal Mobile Device (PMD) n n n n E.g., smart phones, tablets, electronic glasses, apple watch Is battery operated Connects to the Internet via wireless Several hundreds dollars n Cloud computing n n n Servers are replaced by cloud computing n E.g., Amazon, Google, MS, Apple, Adobe (see next slide) Warehouse-Scale Computers (WSC) Software as a Service (SaaS) n Revolutionizing the software industry On the other hand n Portion of software run on a PMD, and a portion run in the Cloud 5 6 3

4 Netflix uses AWS for a wide variety of features: It keeps track of all of its users, their preferences, what they watch, what they click on, and the company organizes its massive catalog of content in the cloud. Netflix remembers exactly where you last stopped watching something and picks it right back up from there hours, days or even weeks later. It seems like magic. And a lot of it is run out of Amazon s cloud. But there s a whole lot of other magic that happens that s not run out of Amazon s cloud. Netflix operates its own Content Delivery Network, named Open Connect, in which it stores the video content is streams to users in data centers around the world to be as close to its end users as possible. The best way to express it is that everything you see on Netflix up until the play button is on AWS, the actual video is delivered through our CDN, Netflix 7 spokesperson Joris Evers said. 8 4

5 Trend of the PostPC Era 2014 The number manufactured per year for tablets and smart phones. 9 Warren Buffett showed off his retro Samsung flip phone on CNBC's "Squawk Box. //01/10/

6 Intel is becoming a post-pc company Elizabeth Weise, USATODAY 6:49 a.m. EST January 14, 2016 SAN FRANCISCO Intel wants to make clear it's not as dependent on the waning PC market, showcasing with some fanfare how its technology can make shoes, drones, even skateboards smarter. Its results, out late Thursday, will likely reflect some of those strides. But strength from areas outside core PC chips are likely to come from supplying data centers, a market it entered via a large acquisition, than the flashier Internet of Things arena. (Photo: Sam Morris, Las Vegas News Bureau via EPA) Intel (INTC (/money/lookup/stocks/intc/)) is anticipated to report adjusted earnings per share of 63 cents, down from 74 cents a year ago, as estimated by S&P Capital IQ Consensus Estimates. During the past two quarters, it's beat Street estimates, building up expectations it will pleasantly surprise again. Revenue estimates are $14.8 billion, compared with guidance of $14.3 to $15.3 billion and close to flat with a year ago. The biggest news for many analysts is that Intel seems to have turned the corner, moving from being mainly a producer of chips for PC to producing a much broader and more diversified lineup. USA TODAY Intel CEO's glitzy keynote emphasizes computers as an extension of you ( One example was Intel s $16.7 billion acquisition of Altera (/story/money/2015/06/01/altera-intel-deal-chips-semis/ /), finalized last month. Altera makes programmable chips, which are key in data centers and the Internet of Things. Intel also signaled its future intentions with the purchase earlier this month of German drone company Ascending Technologies. The company had already been partnering with Intel, using its RealSense cameras to help drones avoid obstacles. Intel has accepted that PCs are a diminishing market. According to a report released Wednesday by the research firm Gartner, global PC shipments fell 11 for the fifth consecutive quarter. Overall, global shipments in the fourth quarter fell 8.3%. What to learn from this course? How programs can be translated into a machine language? And how the hardware can execute the programs? What is the hardware/software interface? How software can instruct hardware? What determines program performance? Then, how performance can be improved? How hardware designers can improve performance? Also, multicore CPU, GPU, and parallel processing 12 6

7 When you write a program, how fast it can run? 13 Program Performance? A combination of a few factors Algorithm (time complexity: T(n)) Determines number of operations, I/O operations not covered in this course Programming language, compiler This determine #instructions executed per program Processor and memory system Determine how fast instructions are executed I/O system (including OS and hardware) Determines how fast I/O operations can be executed 14 7

8 Eight Great Ideas Design for Moore s Law Use abstraction to simplify design Make the common case fast Performance via parallelism Performance via pipelining Performance via prediction Hierarchy of memories Dependability via redundancy 15 Computer Systems Have a Layered Design printf; C=A*B; Application software Written in high-level language (HLL) Millions of lines of code System software Compiler: translates HLL code to machine code Operating System: service code Helper, manager, controller Handling input/output Managing CPU, memory and storage Scheduling tasks & sharing resources Hardware CPU, memory, I/O controllers 8

9 Multiple Levels in Software Itself High-level language: Is in a level of abstraction closer to problem domain Mainly designed for productivity and portability Assembly language: Symbolic representation of instructions add, sub Machine language: Binary representation of instructions (0/1 bits) To encode instructions and data sort(), printf() 17 Below Your Program High-level language program (in C) swap (int v[], int k) ( int temp; temp = v[k]; v[k] = v[k+1]; v[k+1] = temp; ) Assembly language program (for MIPS) swap: sll $2, $5, 2 add $2, $4, $2 lw $15, 0($2) lw $16, 4($2) sw $16, 0($2) sw $15, 4($2) jr $31 one-to-many one-to-one Machine (object, binary) code (for MIPS) C compiler assembler 18 9

10 Advantages of Higher-Level Languages Higher-level languages Allow the programmer to think in a more natural language, and for their intended use (Fortran for scientific computation, Cobol for business programming, Lisp for symbol manipulation, Java for web programming, ) Improve programmer productivity Improve program maintainability - more understandable code is easier to debug and validate Allow programs to be independent of the computer, on which they are developed (compilers and assemblers can translate high-level language programs to the binary instructions of any machine) Emergence of optimizing compilers that produce very efficient assembly code (optimized for the target machine) 19 Evaluating performance Components of a Computer The BIG Picture interface 5 4 compiler 3 The underlying hardware in all computers provide the same basic functions Five components for all kinds of computer Input/output includes User-interface devices keyboard, mouse, display Storage devices Hard disk, CD/DVD, flash Network adapters wireless, for communicating with other computers Start with I/O devices Fig. Organization of a computer, indendent of hardware technology

11 The Graphics Display LCD screen: an array of pixels (~2 minutes) Used to mirror content of frame buffer One LCD Pixel 21 (~2 minutes) 22 11

12 1/11/18 Touchscreen A PostPC device Supersedes keyboard and mouse Capacitive Sensing Glass covered with a transparent conductor People are electrical conductor Capacitive allows multiple touches simultaneously Opening an ipad2 Box (2011) $127 Capacitive multitouch LCD screen 3.8 V, 25 Watt-hour battery $25 $65(DRAM +Flash) Computer board $

13 Processor Datapath: perform the arithmetic operations Control: tell datapath, memory, I/O what to do according to the instructions. Cache (not shown): Small fast SRAM memory for immediate access to data 25 Revisiting Abstractions Abstraction helps us deal with complexity Hide lower-level detail Instruction set architecture (ISA) i.e., the hardware/software interface Nothing related to implementation Application binary interface (ABI) ISA + system software interface 26 13

14 Memory: Place to Store Data Volatile primary memory Loses instructions and data when power off Non-volatile secondary memory Magnetic disk Flash memory Optical disk (CDROM, DVD) Networks Local area network (LAN): Ethernet Wide area network (WAN): the Internet Wireless network: WiFi, Bluetooth Advantages: Communication, resource sharing, nonlocal accesses 28 14

15 Technologies Over Time Computer Tech continues to evolve very fast Increased capacity Better performance Lower cost Lower energy DRAM capacity Year Manufacture ProcessTechnology Relative performance/cost 1951 Vacuum tube Transistor Integrated circuit (IC) Very large scale IC (VLSI) 2,400, Ultra large scale IC 250,000,000, nm technology Integrated circuit is built from silicon-based CMOS technology The size of a transistor is in nm nm 14 nm 10 nm 7 nm Manufacturing Development Research 14 nm Process Blood Cell 7 um Virus 100 nm Silicon Atom 0.24 nm 30 15

16 Transistor Performance vs. Leakage high voltage 65 nm 45 nm 32 nm 22 nm 14 nm 1x Server Computing Lower Leakage Power 0.1x 0.01x Client Computing Mobile Computing low voltage 0.001x Mobile Always-On Circuits Higher Transistor Performance (switching speed) to support a wide range of products 31 A Tick Advances Manufacturing Technology A Tock Delivers New Microarchitecture