1. Memory/Storage Architecture Lab 1 Virtualization History of Computing = History of Virtualization  e.g., process abstraction, virtual memory, cache memory, virtual machine, simultaneous multithreading (SMT),…(the list goes on) Illusion

2. Memory/Storage Architecture Lab 2 Virtualization Example: Process abstraction + = CPU Time Multiplexing of physical CPU within the operating system (OS) using timer circuit/interrupt CPU Single physical CPU Multiple logical CPUs Source: http://bwrc.eecs.berkeley.edu/ CIC/die_photos/21164.gif

3. Memory/Storage Architecture Lab 3 Virtualization Example: Virtual Memory + Dedicated (virtual) Memory for each process = DRAM Hard Disk

4. Memory/Storage Architecture Lab 4 Two Aspects of Virtualization  Functionality Hardware: MMU (memory management unit) and exception mechanism (“page fault”) Software: virtual memory management routines based on page tables, one for each process, in the operating system (OS)  Performance Optimizing regular memory references − Temporal locality (locality in time) If an item is referenced, it will tend to be referenced again soon. − Spatial locality (locality in space) If an item is referenced, items whose addresses are close by will tend to be referenced soon. Optimizing page table references − TLB (Translation Look-aside Buffer)

5. Memory/Storage Architecture Lab 5 Typical Workload Pattern Source: Glass & Cao (1997 ACM SIGMETRICS)

6. Memory/Storage Architecture Lab 6 Virtualization Example: Cache Memory += New Memory Technology (Performance: SRAM) (Cost: DRAM) SRAM DRAM

7. Memory/Storage Architecture Lab 7 Virtualization Example: Virtual Machine Thin software layer below operating system + e.g., VMware, VirtualPC, Connectix Virtual PC =... LinuxWindows XP