CIT 668: System Architecture

Transcription

1 CIT 668: System Architecture Computer Systems Architecture I 1. System Components 2. Processor 3. Memory 4. Storage 5. Network 6. Operating System Topics Images courtesy of Majd F. Sakr or from Wikipedia unless otherwise noted. A Single CPU Computer Components 1

2 Von Neumann Architecture Single storage for both data and commands Storage separate from control unit RAM CPU The Brain von Neumann 4 The 5 Von Neumann Components Input/Output CPU and ALU Memory Motherboard 2

3 The Processor The Processor The Brain: a functional unit that interprets and carries out instructions (mathematical operations) Also called a CPU (actually includes CPU + ALU) Consists of hundreds of millions of transistors. Instruction Set Architecture (ISA) Every processor has its own set of operations Written in binary machine language (ML) Each instruction consists of operator + operand Assembly language is humanly-readable ML Category Arithmetic Logic Program Control Data Movement I/O Example Add, subtract, multiply, divide And, or, not, exclusive ov Branch (conditional), call, jump Move, load, store Read, write 3

4 Source Code to Machine Language Program Execution Cycle Fetch/Execute Cycle Fetch: retrieve instruction from memory Execute: decode instruction, fetch operands, execute instruction, store results to memory (if any) Fetch Store Decode Execute Synchronous Execution Each step waits for click tick to begin A 100 MHz processor uses a clock that ticks 100,000,000 times per second. Fetch Store Decode Cycle speed of 1 GHz: billionths of a second Execute 4

5 Processor Components Processor Layout From Sand to Silicon Wafers Purification and heating to make a pure silicon crystal. Sand, made up of 25% silicon, is the starting point 100kg of % pure silicon crystal Slicing the crystal into 300mm wafers for use in photolithography. 5

6 Photolithography Packaging Wafer is cut into dies, each containing one processor. Substrate, die, and heatspreader assembled to make final CPU product for use in a PC. Processor Components: Control Control Unit Processor s supervisor Fetch/execute cycle Retrieve instruction Decode instruction Execute actions Program Counter (PC): stores address of instruction to be fetched. Instruction Register (IR): has instruction most recently fetched. 6

7 Processor Components: Datapath Register File: General purpose storage locations inside processor that hold addresses or values. Arithmetic Logic Unit: Set of functional units that perform arithmetic and logic operations. A 32-bit processor has registers that are typically 32 bits in size. Superscalar Architecture Instead of one ALU, use multiple execution units Some execution units are identical to others Others are different: Integer, FPU, multi-media AMD Athlon Architecture 7

8 Computer System Layers Moore s Law Number of transistors doubles every 18 months More transistors = Cheaper CPUs Higher speeds More features More cache 23 Improvements in CPU Clock Speed 8

9 Power Density (W/cm 2 ) Computation Produces Heat Processor Power Density Sun s Surface Rocket Nozzle Nuclear Reactor Pentium IV Pentium III Pentium II 8086 Hot Plate Pentium Pro Pentium Year Source: Intel 26 The Single CPU is History What can you do with more transistors at same speed? Multicore CPUs Multiple processors (cores) on a single chip Run different programs on each core Some programs can be rewritten to run on multiple cores: PhotoShop, bzip2 Most of you are running multi-core 9

10 2011 Server CPUs Intel Xeon Up to to 3.3 GHz Up to 18 MB L3 cache AMD Opteron 4, 6, 8, or to 3.2 GHz Up to 12 MB L3 cache IBM Power 7 4, 6, or to 4.25 GHz 4 MB L3 cache per core (up to 32MB for 8-core) Sun Niagara GHz 6 MB L2 cache End of Moore s Law Si 0.3 nm Where do we go from here? Better Materials More Machines Better Algorithms GaAs Cloud Map Reduce Diamond Containers Fuzzy Logic 10

11 Processor-Memory Gap 11