6.172 Performance Engineering of Software Systems Spring Lecture 9. P after. Figure 1: A diagram of the stack (Image by MIT OpenCourseWare.
|
|
- Georgina Cummings
- 5 years ago
- Views:
Transcription
1 6.172 Performance Engineering of Software Systems Spring 2009 Lecture 9 MIT OpenCourseWare Dynamic Storage Allocation Stack allocation: LIFO (last-in-first-out) Array and pointer A used unused P before P after Allocate x bytes: q = p; p += x; return q; Figure 1: A diagram of the stack (Image by MIT OpenCourseWare.) O(1) time Few operations and good cache behavior (temporal and spatial) Free: p = q; O(1) time Issues: Inline (especially for small allocations) May want to round up to word (or cache block) boundary Must free consistent with stack discipline limited applicability, but fast when it works. Can sometimes use call stacks, e.g. alloca() (free free()) alloca() is depreciated [hard to control stack size in some environments and compiler is more efficient with fixed-size function activation records (frames)] Heap allocation (not heap data structure) C: malloc() and free() C++: new and delete Unlike Java and Python, C/C++ has no garbage collector. Storage that is allocated must be freed explicitly by programmer. Otherwise, memory leak! Also watch for dangling pointers and double frees. 1
2 Fixed-size allocation A nil free list Figure 2: A diagram of a free list (Image by MIT OpenCourseWare.) Allocation: remove head of free list O(1) time Free: add block to free list O(1) time Few ops and good locality Problem. External fragmentation: blocks distributed across memory loss of spatial locality Variable-size allocation Idea: Leverage efficiency of fixed-size allocation. Accept some internal fragmentation. Binned free lists Allocator supports a reduced set of canonical sizes, typically {1, 2, 4, 8, 16,...} (or slightly larger for bookkeeping info, cache alignment) largest requested block size r Figure 3: A diagram of a binned-free list (Image by MIT OpenCourseWare.) Allocate x: look in bin lg x if empty, find block in larger bin and split No larger blocks, allocate new address space. 2
3 stack dynamically allocated heap uninitialized data bss initialized data initialized to0 at program start read from program file high addr low addr code Figure 4: The typical storage layout of a program(image by MIT OpenCourseWare.) Question: 64-bit virtual memory (VM) never run out of address space. Why not just allocate what you need and never free? Answer: VM is backed up by physical memory, e.g. disk. Also, severe external fragmentation. Goal: use as little VM as possible. Theorem. Let M be the maximum amount of memory in use at any time by a program. Then binned free lists uses at most O(M lg M) VM address space. Proof. No bin ever contains more than }{{} 2M memory. At most lg(2m) bins. round up Theorem. Let M be the VM address space used by the optimal allocator (with no coalescing). Then binned free lists uses at most 6M VM address space. Coalescing Splice adjacent blocks together to make larger blocks 3
4 Ameliorates external fragmentation No good bounds on effectiveness Works in practice, because storage tends to be deallocated as a stack (LIFO) or in batches. Clever schemes for finding adjacent blocks, e.g. buddy system Garbage collection Idea: Rather than user freeing storage, runtime does it. Built-in (Java, Python) (or build by hand) Roots: storage directly accessible (global vars, stack). Objects not reachable from roots through pointers can be recycled. Key issues: Identify pointers in objects (strong typing) Prohibit pointer arithmetic - may slow down some codes. Reference counting Keep count of number of pointers to each object. If pointer count drops to 0, put in free list Figure 5: A diagram of reference counting garbage collection (Image by MIT OpenCourseWare.) Problem. Cycle never garbage collected. Nevertheless, good scheme for acyclic structures. 4
5 Abstraction Objects form a directed graph. Garbage Collected objects not reachable from roots. graph searching (e.g., DFS or BFS) Recall BFS: Example. Mark roots and put into FIFO Q; (a bitfield) while (Q not empty) { u = dequeue(q); for (each (u,v) incident on u) { if (v unmarked) { mark v; enqueue(q,v); } } } a b f g r c e i d h j Figure 6: A diagram of a BFS (Image by MIT OpenCourseWare.) Q : r cd ef g Observation: All reachable objects are placed in contiguous storage in Q. Copying GC: From space dead To space live live next allocation next allocation Figure 7: A diagram of a copying garbage collector (Image by MIT OpenCourseWare.) When From space is full, copy to To space. 5
6 Issue: Since To address is different than the From address, pointers must be updated. I. When object copied to To space, store forwarding pointer in From object, which implicitly marks it as moved. II. When object removed from Q in To space, update all its pointers. Example. Before From To After head tail From To head tail Figure 8: A diagram of a copying garbage collector (Image by MIT OpenCourseWare.) Linear time After copying, allocate new unused space equal to (or constant fraction of) used space amortize GC time, keep VM address space small. From To used unused Figure 9: A diagram of a copying garbage collector (Image by MIT OpenCourseWare.) Old To becomes new From New To allocated at start if room, otherwise after new From VM address space constant optimal 6
7 Other GC Strategies mark and sweep generational 7
8 MIT OpenCourseWare Performance Engineering of Software Systems Fall 2009 For information about citing these materials or our Terms of Use, visit:
Dynamic Storage Allocation
6.172 Performance Engineering of Software Systems LECTURE 10 Dynamic Storage Allocation Charles E. Leiserson October 12, 2010 2010 Charles E. Leiserson 1 Stack Allocation Array and pointer A un Allocate
More informationRun-time Environments -Part 3
Run-time Environments -Part 3 Y.N. Srikant Computer Science and Automation Indian Institute of Science Bangalore 560 012 NPTEL Course on Compiler Design Outline of the Lecture Part 3 What is run-time support?
More informationRun-Time Environments/Garbage Collection
Run-Time Environments/Garbage Collection Department of Computer Science, Faculty of ICT January 5, 2014 Introduction Compilers need to be aware of the run-time environment in which their compiled programs
More informationRun-time Environments - 3
Run-time Environments - 3 Y.N. Srikant Computer Science and Automation Indian Institute of Science Bangalore 560 012 NPTEL Course on Principles of Compiler Design Outline of the Lecture n What is run-time
More informationA.Arpaci-Dusseau. Mapping from logical address space to physical address space. CS 537:Operating Systems lecture12.fm.2
UNIVERSITY of WISCONSIN-MADISON Computer Sciences Department CS 537 A. Arpaci-Dusseau Intro to Operating Systems Spring 2000 Dynamic Memory Allocation Questions answered in these notes When is a stack
More informationMotivation for Dynamic Memory. Dynamic Memory Allocation. Stack Organization. Stack Discussion. Questions answered in this lecture:
CS 537 Introduction to Operating Systems UNIVERSITY of WISCONSIN-MADISON Computer Sciences Department Dynamic Memory Allocation Questions answered in this lecture: When is a stack appropriate? When is
More informationRuntime. The optimized program is ready to run What sorts of facilities are available at runtime
Runtime The optimized program is ready to run What sorts of facilities are available at runtime Compiler Passes Analysis of input program (front-end) character stream Lexical Analysis token stream Syntactic
More informationMITOCW MIT6_172_F10_lec10_300k-mp4
MITOCW MIT6_172_F10_lec10_300k-mp4 The following content is provided under a Creative Commons license. Your support will help MIT OpenCourseWare continue to offer high-quality educational resources for
More informationCS61C : Machine Structures
inst.eecs.berkeley.edu/~cs61c/su06 CS61C : Machine Structures Lecture #6: Memory Management CS 61C L06 Memory Management (1) 2006-07-05 Andy Carle Memory Management (1/2) Variable declaration allocates
More informationDynamic Memory Management
Dynamic Memory Management 1 Goals of this Lecture Help you learn about: Dynamic memory management techniques Garbage collection by the run-time system (Java) Manual deallocation by the programmer (C, C++)
More informationDynamic Memory Management! Goals of this Lecture!
Dynamic Memory Management!!! 1 Goals of this Lecture! Help you learn about:! Dynamic memory management techniques! Garbage collection by the run-time system (Java)! Manual deallocation by the programmer
More informationDynamic Memory Management
Dynamic Memory Management Professor Jennifer Rexford http://www.cs.princeton.edu/~jrex 1 Goals of Today s Lecture Dynamic memory management o Garbage collection by the run-time system (Java) o Manual deallocation
More informationIn Java we have the keyword null, which is the value of an uninitialized reference type
+ More on Pointers + Null pointers In Java we have the keyword null, which is the value of an uninitialized reference type In C we sometimes use NULL, but its just a macro for the integer 0 Pointers are
More informationAutomatic Memory Management
Automatic Memory Management Why Automatic Memory Management? Storage management is still a hard problem in modern programming Why Automatic Memory Management? Storage management is still a hard problem
More informationCS 241 Honors Memory
CS 241 Honors Memory Ben Kurtovic Atul Sandur Bhuvan Venkatesh Brian Zhou Kevin Hong University of Illinois Urbana Champaign February 20, 2018 CS 241 Course Staff (UIUC) Memory February 20, 2018 1 / 35
More informationG Programming Languages - Fall 2012
G22.2110-003 Programming Languages - Fall 2012 Lecture 2 Thomas Wies New York University Review Last week Programming Languages Overview Syntax and Semantics Grammars and Regular Expressions High-level
More informationCS61C Midterm Review on C & Memory Management
CS61C Midterm Review on C & Memory Management Fall 2006 Aaron Staley Some material taken from slides by: Michael Le Navtej Sadhal Overview C Array and Pointer Goodness! Memory Management The Three Three
More informationCMSC 330: Organization of Programming Languages
CMSC 330: Organization of Programming Languages Memory Management and Garbage Collection CMSC 330 - Spring 2013 1 Memory Attributes! Memory to store data in programming languages has the following lifecycle
More informationLecture 13: Garbage Collection
Lecture 13: Garbage Collection COS 320 Compiling Techniques Princeton University Spring 2016 Lennart Beringer/Mikkel Kringelbach 1 Garbage Collection Every modern programming language allows programmers
More informationMemory Allocation. Static Allocation. Dynamic Allocation. Dynamic Storage Allocation. CS 414: Operating Systems Spring 2008
Dynamic Storage Allocation CS 44: Operating Systems Spring 2 Memory Allocation Static Allocation (fixed in size) Sometimes we create data structures that are fixed and don t need to grow or shrink. Dynamic
More informationCMSC 330: Organization of Programming Languages
CMSC 330: Organization of Programming Languages Memory Management and Garbage Collection CMSC 330 Spring 2017 1 Memory Attributes Memory to store data in programming languages has the following lifecycle
More informationCMSC 330: Organization of Programming Languages. Memory Management and Garbage Collection
CMSC 330: Organization of Programming Languages Memory Management and Garbage Collection CMSC330 Fall 2018 1 Memory Attributes Memory to store data in programming languages has the following lifecycle
More informationRobust Memory Management Schemes
Robust Memory Management Schemes Prepared by : Fadi Sbahi & Ali Bsoul Supervised By: Dr. Lo ai Tawalbeh Jordan University of Science and Technology Robust Memory Management Schemes Introduction. Memory
More informationCompilers. 8. Run-time Support. Laszlo Böszörmenyi Compilers Run-time - 1
Compilers 8. Run-time Support Laszlo Böszörmenyi Compilers Run-time - 1 Run-Time Environment A compiler needs an abstract model of the runtime environment of the compiled code It must generate code for
More informationDynamic Memory Allocation
Dynamic Memory Allocation CS61, Lecture 10 Prof. Stephen Chong October 4, 2011 Announcements 1/2 Assignment 4: Malloc Will be released today May work in groups of one or two Please go to website and enter
More informationMemory Management. Memory Management... Memory Management... Interface to Dynamic allocation
CSc 453 Compilers and Systems Software 24 : Garbage Collection Introduction Department of Computer Science University of Arizona collberg@gmail.com Copyright c 2009 Christian Collberg Dynamic Memory Management
More informationHeap Management. Heap Allocation
Heap Management Heap Allocation A very flexible storage allocation mechanism is heap allocation. Any number of data objects can be allocated and freed in a memory pool, called a heap. Heap allocation is
More informationCompiler Construction
Compiler Construction Lecture 18: Code Generation V (Implementation of Dynamic Data Structures) Thomas Noll Lehrstuhl für Informatik 2 (Software Modeling and Verification) noll@cs.rwth-aachen.de http://moves.rwth-aachen.de/teaching/ss-14/cc14/
More informationOne-Slide Summary. Lecture Outine. Automatic Memory Management #1. Why Automatic Memory Management? Garbage Collection.
Automatic Memory Management #1 One-Slide Summary An automatic memory management system deallocates objects when they are no longer used and reclaims their storage space. We must be conservative and only
More informationHeap Management portion of the store lives indefinitely until the program explicitly deletes it C++ and Java new Such objects are stored on a heap
Heap Management The heap is the portion of the store that is used for data that lives indefinitely, or until the program explicitly deletes it. While local variables typically become inaccessible when
More informationCS 536 Introduction to Programming Languages and Compilers Charles N. Fischer Lecture 11
CS 536 Introduction to Programming Languages and Compilers Charles N. Fischer Lecture 11 CS 536 Spring 2015 1 Handling Overloaded Declarations Two approaches are popular: 1. Create a single symbol table
More informationCSE P 501 Compilers. Memory Management and Garbage Collec<on Hal Perkins Winter UW CSE P 501 Winter 2016 W-1
CSE P 501 Compilers Memory Management and Garbage Collec
More informationDynamic Memory Allocation
Dynamic Memory Allocation CS61, Lecture 11 Prof. Stephen Chong October 6, 2011 Announcements 1/2 Reminder: No section on Monday Monday sections have been rescheduled See website for details Please attend
More informationRequirements, Partitioning, paging, and segmentation
Requirements, Partitioning, paging, and segmentation Main Memory: The Big Picture kernel memory proc struct kernel stack/u area Stack kernel stack/u area Stack kernel stack/u area Stack Data Text (shared)
More informationCompiler Construction
Compiler Construction Thomas Noll Software Modeling and Verification Group RWTH Aachen University https://moves.rwth-aachen.de/teaching/ss-16/cc/ Recap: Static Data Structures Outline of Lecture 18 Recap:
More informationECE 598 Advanced Operating Systems Lecture 10
ECE 598 Advanced Operating Systems Lecture 10 Vince Weaver http://www.eece.maine.edu/~vweaver vincent.weaver@maine.edu 17 February 2015 Announcements Homework #1 and #2 grades, HW#3 Coming soon 1 Various
More informationGarbage Collection. Steven R. Bagley
Garbage Collection Steven R. Bagley Reference Counting Counts number of pointers to an Object deleted when the count hits zero Eager deleted as soon as it is finished with Problem: Circular references
More informationGarbage Collection. Hwansoo Han
Garbage Collection Hwansoo Han Heap Memory Garbage collection Automatically reclaim the space that the running program can never access again Performed by the runtime system Two parts of a garbage collector
More informationAcknowledgements These slides are based on Kathryn McKinley s slides on garbage collection as well as E Christopher Lewis s slides
Garbage Collection Last time Compiling Object-Oriented Languages Today Motivation behind garbage collection Garbage collection basics Garbage collection performance Specific example of using GC in C++
More informationRequirements, Partitioning, paging, and segmentation
Requirements, Partitioning, paging, and segmentation Memory Management Subdividing memory to accommodate multiple processes Memory needs to be allocated efficiently to pack as many processes into memory
More informationA program execution is memory safe so long as memory access errors never occur:
A program execution is memory safe so long as memory access errors never occur: Buffer overflows, null pointer dereference, use after free, use of uninitialized memory, illegal free Memory safety categories
More informationMemory Management. Didactic Module 14 Programming Languages - EEL670 1
Memory Management Didactic Module 14 Programming Languages - EEL670 1 Dynamic Memory Allocation Lots of things need memory at runtime: Activation records Objects Explicit allocations: new, malloc, etc.
More informationMemory Management. Chapter Fourteen Modern Programming Languages, 2nd ed. 1
Memory Management Chapter Fourteen Modern Programming Languages, 2nd ed. 1 Dynamic Memory Allocation Lots of things need memory at runtime: Activation records Objects Explicit allocations: new, malloc,
More informationECE 2035 Programming HW/SW Systems Fall problems, 5 pages Exam Three 28 November 2012
Instructions: This is a closed book, closed note exam. Calculators are not permitted. If you have a question, raise your hand and I will come to you. Please work the exam in pencil and do not separate
More informationMemory management. Johan Montelius KTH
Memory management Johan Montelius KTH 2017 1 / 22 C program # include int global = 42; int main ( int argc, char * argv []) { if( argc < 2) return -1; int n = atoi ( argv [1]); int on_stack
More informationMemory Management 3/29/14 21:38
Presentation for use with the textbook Data Structures and Algorithms in Java, 6 th edition, by M. T. Goodrich, R. Tamassia, and M. H. Goldwasser, Wiley, 2014 Memory Management Diagram of a 4 4 plane of
More informationManaged runtimes & garbage collection. CSE 6341 Some slides by Kathryn McKinley
Managed runtimes & garbage collection CSE 6341 Some slides by Kathryn McKinley 1 Managed runtimes Advantages? Disadvantages? 2 Managed runtimes Advantages? Reliability Security Portability Performance?
More informationImplementation Garbage Collection
CITS 3242 Programming Paradigms Part IV: Advanced Topics Topic 19: Implementation Garbage Collection Most languages in the functional, logic, and object-oriented paradigms include some form of automatic
More informationName, Scope, and Binding. Outline [1]
Name, Scope, and Binding In Text: Chapter 3 Outline [1] Variable Binding Storage bindings and lifetime Type bindings Type Checking Scope Lifetime vs. Scope Referencing Environments N. Meng, S. Arthur 2
More information10.1. CS356 Unit 10. Memory Allocation & Heap Management
10.1 CS356 Unit 10 Memory Allocation & Heap Management 10.2 BASIC OS CONCEPTS & TERMINOLOGY 10.3 User vs. Kernel Mode Kernel mode is a special mode of the processor for executing trusted (OS) code Certain
More informationManaged runtimes & garbage collection
Managed runtimes Advantages? Managed runtimes & garbage collection CSE 631 Some slides by Kathryn McKinley Disadvantages? 1 2 Managed runtimes Portability (& performance) Advantages? Reliability Security
More informationProgramming Language Implementation
A Practical Introduction to Programming Language Implementation 2014: Week 10 Garbage Collection College of Information Science and Engineering Ritsumeikan University 1 review of last week s topics dynamic
More informationClass Information ANNOUCEMENTS
Class Information ANNOUCEMENTS Third homework due TODAY at 11:59pm. Extension? First project has been posted, due Monday October 23, 11:59pm. Midterm exam: Friday, October 27, in class. Don t forget to
More informationLecture 7: Binding Time and Storage
Lecture 7: Binding Time and Storage COMP 524 Programming Language Concepts Stephen Olivier February 5, 2009 Based on notes by A. Block, N. Fisher, F. Hernandez-Campos, and D. Stotts Goal of Lecture The
More informationGarbage Collection Algorithms. Ganesh Bikshandi
Garbage Collection Algorithms Ganesh Bikshandi Announcement MP4 posted Term paper posted Introduction Garbage : discarded or useless material Collection : the act or process of collecting Garbage collection
More informationGarbage Collection. Akim D le, Etienne Renault, Roland Levillain. May 15, CCMP2 Garbage Collection May 15, / 35
Garbage Collection Akim Demaille, Etienne Renault, Roland Levillain May 15, 2017 CCMP2 Garbage Collection May 15, 2017 1 / 35 Table of contents 1 Motivations and Definitions 2 Reference Counting Garbage
More informationManual Allocation. CS 1622: Garbage Collection. Example 1. Memory Leaks. Example 3. Example 2 11/26/2012. Jonathan Misurda
Manual llocation Dynamic memory allocation is an obvious necessity in a programming environment. S 1622: Garbage ollection Many programming languages expose some functions or keywords to manage runtime
More informationLectures 13 & 14. memory management
Lectures 13 & 14 Linked lists and memory management Courtesy of Prof. Garcia (UCB) CS61C L05 Introduction to C (pt 3) (1) Review Pointers and arrays are virtually same C knows how to increment pointers
More informationBinding and Storage. COMP 524: Programming Language Concepts Björn B. Brandenburg. The University of North Carolina at Chapel Hill
Binding and Storage Björn B. Brandenburg The University of North Carolina at Chapel Hill Based in part on slides and notes by S. Olivier, A. Block, N. Fisher, F. Hernandez-Campos, and D. Stotts. What s
More informationLecture 14. No in-class files today. Homework 7 (due on Wednesday) and Project 3 (due in 10 days) posted. Questions?
Lecture 14 No in-class files today. Homework 7 (due on Wednesday) and Project 3 (due in 10 days) posted. Questions? Friday, February 11 CS 215 Fundamentals of Programming II - Lecture 14 1 Outline Static
More informationExploiting the Behavior of Generational Garbage Collector
Exploiting the Behavior of Generational Garbage Collector I. Introduction Zhe Xu, Jia Zhao Garbage collection is a form of automatic memory management. The garbage collector, attempts to reclaim garbage,
More informationDynamic Memory: Alignment and Fragmentation
Dynamic Memory: Alignment and Fragmentation Learning Objectives Explain the purpose of dynamic memory Define the terms arena, heap Identify common errors involving dynamic memory Explain how dynamic memory
More informationLast week. Data on the stack is allocated automatically when we do a function call, and removed when we return
Last week Data can be allocated on the stack or on the heap (aka dynamic memory) Data on the stack is allocated automatically when we do a function call, and removed when we return f() {... int table[len];...
More informationAdvanced Programming & C++ Language
Advanced Programming & C++ Language ~6~ Introduction to Memory Management Ariel University 2018 Dr. Miri (Kopel) Ben-Nissan Stack & Heap 2 The memory a program uses is typically divided into four different
More informationRun-time Environments
Run-time Environments Status We have so far covered the front-end phases Lexical analysis Parsing Semantic analysis Next come the back-end phases Code generation Optimization Register allocation Instruction
More informationCSE373: Data Structures & Algorithms Lecture 12: Amortized Analysis and Memory Locality. Lauren Milne Spring 2015
CSE373: Data Structures & Algorithms Lecture 12: Amortized Analysis and Memory Locality Lauren Milne Spring 2015 Announcements Homework 3 due on Wednesday at 11pm Catie back Monday Spring 2015 CSE 373
More informationLANGUAGE RUNTIME NON-VOLATILE RAM AWARE SWAPPING
Technical Disclosure Commons Defensive Publications Series July 03, 2017 LANGUAGE RUNTIME NON-VOLATILE AWARE SWAPPING Follow this and additional works at: http://www.tdcommons.org/dpubs_series Recommended
More informationRun-time Environments
Run-time Environments Status We have so far covered the front-end phases Lexical analysis Parsing Semantic analysis Next come the back-end phases Code generation Optimization Register allocation Instruction
More informationDynamic Memory Allocation: Advanced Concepts
Dynamic Memory Allocation: Advanced Concepts Keeping Track of Free Blocks Method 1: Implicit list using length links all blocks 5 4 6 Method : Explicit list among the free blocks using pointers 5 4 6 Kai
More informationCSC 1600 Memory Layout for Unix Processes"
CSC 16 Memory Layout for Unix Processes" 1 Lecture Goals" Behind the scenes of running a program" Code, executable, and process" Memory layout for UNIX processes, and relationship to C" : code and constant
More informationExample. program sort; var a : array[0..10] of integer; procedure readarray; : function partition (y, z :integer) :integer; var i, j,x, v :integer; :
Runtime Environment Relationship between names and data objects (of target machine) Allocation & de-allocation is managed by run time support package Each execution of a procedure is an activation of the
More informationLimitations of the stack
The heap hic 1 Limitations of the stack int *table_of(int num, int len) { int table[len+1]; for (int i=0; i
More informationCS558 Programming Languages
CS558 Programming Languages Fall 2017 Lecture 3a Andrew Tolmach Portland State University 1994-2017 Binding, Scope, Storage Part of being a high-level language is letting the programmer name things: variables
More information(notes modified from Noah Snavely, Spring 2009) Memory allocation
CS 1114: Data Structures memory allocation! Prof. Graeme Bailey http://cs1114.cs.cornell.edu (notes modified from Noah Snavely, Spring 2009) Memory allocation! Strategy 1: Computer keep tracks of free
More informationA new Mono GC. Paolo Molaro October 25, 2006
A new Mono GC Paolo Molaro lupus@novell.com October 25, 2006 Current GC: why Boehm Ported to the major architectures and systems Featurefull Very easy to integrate Handles managed pointers in unmanaged
More informationGarbage Collection (1)
Garbage Collection (1) Advanced Operating Systems Lecture 7 This work is licensed under the Creative Commons Attribution-NoDerivatives 4.0 International License. To view a copy of this license, visit http://creativecommons.org/licenses/by-nd/4.0/
More informationMemory Management Basics
Memory Management Basics 1 Basic Memory Management Concepts Address spaces! Physical address space The address space supported by the hardware Ø Starting at address 0, going to address MAX sys! MAX sys!!
More informationSimple Garbage Collection and Fast Allocation Andrew W. Appel
Simple Garbage Collection and Fast Allocation Andrew W. Appel Presented by Karthik Iyer Background Motivation Appel s Technique Terminology Fast Allocation Arranging Generations Invariant GC Working Heuristic
More informationCS 345. Garbage Collection. Vitaly Shmatikov. slide 1
CS 345 Garbage Collection Vitaly Shmatikov slide 1 Major Areas of Memory Static area Fixed size, fixed content, allocated at compile time Run-time stack Variable size, variable content (activation records)
More informationLecture Notes on Garbage Collection
Lecture Notes on Garbage Collection 15-411: Compiler Design Frank Pfenning Lecture 21 November 4, 2014 These brief notes only contain a short overview, a few pointers to the literature with detailed descriptions,
More informationComputer Systems A Programmer s Perspective 1 (Beta Draft)
Computer Systems A Programmer s Perspective 1 (Beta Draft) Randal E. Bryant David R. O Hallaron August 1, 2001 1 Copyright c 2001, R. E. Bryant, D. R. O Hallaron. All rights reserved. 2 Contents Preface
More informationCS61C : Machine Structures
inst.eecs.berkeley.edu/~cs61c CS61C : Machine Structures Lecture 7 More Memory Management CS 61C L07 More Memory Management (1) 2004-09-15 Lecturer PSOE Dan Garcia www.cs.berkeley.edu/~ddgarcia Star Wars
More informationCSE351 Spring 2018, Final Exam June 6, 2018
CSE351 Spring 2018, Final Exam June 6, 2018 Please do not turn the page until 2:30. Last Name: First Name: Student ID Number: Name of person to your left: Name of person to your right: Signature indicating:
More informationACM Trivia Bowl. Thursday April 3 rd (two days from now) 7pm OLS 001 Snacks and drinks provided All are welcome! I will be there.
#1 ACM Trivia Bowl Thursday April 3 rd (two days from now) 7pm OLS 001 Snacks and drinks provided All are welcome! I will be there. If you are in one of the top three teams, I will give you one point of
More information! What is main memory? ! What is static and dynamic allocation? ! What is segmentation? Maria Hybinette, UGA. High Address (0x7fffffff) !
Memory Questions? CSCI [4 6]730 Operating Systems Main Memory! What is main memory?! How does multiple processes share memory space?» Key is how do they refer to memory addresses?! What is static and dynamic
More informationEngine Support System. asyrani.com
Engine Support System asyrani.com A game engine is a complex piece of software consisting of many interacting subsystems. When the engine first starts up, each subsystem must be configured and initialized
More informationLecture 7 More Memory Management Slab Allocator. Slab Allocator
CS61C L07 More Memory Management (1) inst.eecs.berkeley.edu/~cs61c CS61C : Machine Structures Lecture 7 More Memory Management 2006-09-13 Lecturer SOE Dan Garcia www.cs.berkeley.edu/~ddgarcia Unbox problems
More informationMemory Allocation. Copyright : University of Illinois CS 241 Staff 1
Memory Allocation Copyright : University of Illinois CS 241 Staff 1 Recap: Virtual Addresses A virtual address is a memory address that a process uses to access its own memory Virtual address actual physical
More informationECE 598 Advanced Operating Systems Lecture 12
ECE 598 Advanced Operating Systems Lecture 12 Vince Weaver http://web.eece.maine.edu/~vweaver vincent.weaver@maine.edu 1 March 2018 Announcements Next homework will be due after break. Midterm next Thursday
More informationCS Computer Systems. Lecture 8: Free Memory Management
CS 5600 Computer Systems Lecture 8: Free Memory Management Recap of Last Week Last week focused on virtual memory Gives each process the illusion of vast, empty memory Offers protection and isolation 31
More informationCS61C : Machine Structures
inst.eecs.berkeley.edu/~cs61c CS61C : Machine Structures Lecture 7 C Memory Management 2007-02-06 Hello to Said S. from Columbus, OH CS61C L07 More Memory Management (1) Lecturer SOE Dan Garcia www.cs.berkeley.edu/~ddgarcia
More informationMemory Allocation II. CSE 351 Autumn Instructor: Justin Hsia
Memory Allocation II CSE 351 Autumn 2016 Instructor: Justin Hsia Teaching Assistants: Chris Ma Hunter Zahn John Kaltenbach Kevin Bi Sachin Mehta Suraj Bhat Thomas Neuman Waylon Huang Xi Liu Yufang Sun
More informationCS61C : Machine Structures
inst.eecs.berkeley.edu/~cs61c CS61C : Machine Structures Lecture 7 C Memory Management!!Lecturer SOE Dan Garcia!!!www.cs.berkeley.edu/~ddgarcia CS61C L07 More Memory Management (1)! 2010-02-03! Flexible
More informationDeallocation Mechanisms. User-controlled Deallocation. Automatic Garbage Collection
Deallocation Mechanisms User-controlled Deallocation Allocating heap space is fairly easy. But how do we deallocate heap memory no longer in use? Sometimes we may never need to deallocate! If heaps objects
More informationDynamic Memory Allocation. Gerson Robboy Portland State University. class20.ppt
Dynamic Memory Allocation Gerson Robboy Portland State University class20.ppt Harsh Reality Memory is not unbounded It must be allocated and managed Many applications are memory dominated Especially those
More informationCS24: INTRODUCTION TO COMPUTING SYSTEMS. Spring 2017 Lecture 7
CS24: INTRODUCTION TO COMPUTING SYSTEMS Spring 2017 Lecture 7 LAST TIME Dynamic memory allocation and the heap: A run-time facility that satisfies multiple needs: Programs can use widely varying, possibly
More informationDynamic Memory Allocation II October 22, 2008
15-213 Dynamic Memory Allocation II October 22, 2008 Topics Explicit doubly-linked free lists Segregated free lists Garbage collection Review of pointers Memory-related perils and pitfalls class18.ppt
More informationReview! Lecture 5 C Memory Management !
CS61C L05 C Memory Management (1)! inst.eecs.berkeley.edu/~cs61c CS61C : Machine Structures Lecture 5 C Memory Management 2010-06-28!!! Instructor Paul Pearce! Symmetric multiprocessor! MIPS support for
More informationDynamic Memory Allocation. CS 351: Systems Programming Michael Saelee
Dynamic Memory Allocation CS 351: Systems Programming Michael Saelee 1 from: registers cache (SRAM) main memory (DRAM) local hard disk drive (HDD/SSD) remote storage (networked drive / cloud)
More informationProcess s Address Space. Dynamic Memory. Backing the Heap. Dynamic memory allocation 3/29/2013. When a process starts the heap is empty
/9/01 Process s Address Space Dynamic Memory 0x7fffffff Stack Data (Heap) Data (Heap) 0 Text (Code) Backing the Heap When a process starts the heap is empty The process is responsible for requesting memory
More information