CSE 160 Discussion Section. Winter 2017 Week 3
|
|
- Gordon Potter
- 5 years ago
- Views:
Transcription
1 CSE 160 Discussion Section Winter 2017 Week 3
2 Homework 1 - Recap & a few points ComputeMandelbrotPoint func() in smdb.cpp does the job serially. You will have to do the same task in parallel manner in pmdb.cpp block & cyclic partitioning methods taught in the lecture to be used.
3 Recap: Block Partitioning Chunk size = 0, Run without -c option Split the computational box into regions - either horizontal or vertical dimy/nt or dimx/nt Assign a thread to each region Embarrassingly parallel, so no communication between threads
4 Recap: Cyclic Partitioning Round Robin : thread t gets evenly spaced chunks : spaced as chunksize*nt rows apart So core 1 gets strips : 2*1, 2+1*2*3, 2+2*2*3 Balances load evenly Run using -c <chunk size>
5 Notes on Experiments Strong scaling Run for number of threads = 1, 2, 4, 8. Plot parallel speed-up vs number of threads Varying chunk size 8 threads, vary chunk size (-c) from 1 to 8. Plot running time vs chunk size Block vs Cyclic (c=1) 2, 4, 8 threads Block vs Cyclic (c=1) for different bounding box -b , 4, 8 threads
6 Regarding submission: Present your data in Tables / Plots Clear Titles for Table/Plot ex: Strong Scaling Plots using any tool of your choice (Excel/matplotlib/Latex.) Label Rows/Cols of tables and provide axis for plots Brief Analysis on your experiment findings in Report Add Details on implementation (so that we can provide partial credit if code fails to compile) In Report Name [Checklist 1] to help us understand that you have performed the task*
7 Running Jobs on Bang Cluster Interactive : qlogin Non - Interactive Refer : /static/bang/runningjobs.html
8 Interactive Jobs qlogin New shell within $Home dir Edit & Compile code, Run commands on compute node Short/Small jobs Cannot Submit Non-interactive jobs Exclusive Access for 20 mins to a compute node with 8 nodes
9 Non-Interactive Jobs To collect performance measurements To repeat jobs multiple times Space sharing - dedicated access $qsub batch_bang.sh $qstat -u username $qstat -u * - to see all jobs running in queue $qdel job-id to remove a job from queue $qconf -sq debug.q -queue s config parameters $qconf -sq debug.q grep -i h_rt - to get the time limit to run jobs
10 GNU Debugger Open-source debugger Facilities: breakpoints, watches, stepping through code Provides some facilities for multi-threaded programs as well Run with GDB: $gdb./main
11 GNU Debugger - Multi-threaded programs (gdb) b main add a breakpoint at the entry to the function called main Breakpoint 1 at 0x400f46: file main.cpp, line 19. (gdb) r run the program... (gdb) n step to the next line 20 thread t1(foo); line in source code (gdb) n step to the next line [New Thread 0x7ffff6fd6700 (LWP 1418)] 21 thread t2(bar); line in source code (gdb) n [Thread 0x7ffff6fd6700 (LWP 1418) exited] notification of thread completion [New Thread 0x7ffff67d5700 (LWP 1419)] notification of thread creation [Thread 0x7ffff67d5700 (LWP 1419) exited] notification of thread completion 22 cout << x << "\n"; line in source code
12 GNU Debugger - Multi-threaded programs. (gdb) info threads get information about current threads Id Target Id Frame 2 Thread 0x7ffff6fd6700 (LWP 1544) "main" GI nptl_death_event () at events.c:31 * 1 Thread 0x7ffff7fd5780 (LWP 1543) "main" main () at main.cpp:21 * indicates we are controlling thread 1 currently
13 GNU Debugger - Multi-threaded programs. (gdb) info threads get information about current threads Id Target Id Frame 2 Thread 0x7ffff6fd6700 (LWP 1544) "main" GI nptl_death_event () at events.c:31 * 1 Thread 0x7ffff7fd5780 (LWP 1543) "main" main () at main.cpp:21 (gdb) thread 2 switch to thread 2 [Switching to thread 2 (Thread 0x7ffff6fd6700 (LWP 1544))]
14 GNU Debugger - Multi-threaded programs. (gdb) info threads get information about current threads Id Target Id Frame 2 Thread 0x7ffff6fd6700 (LWP 1544) "main" GI nptl_death_event () at events.c:31 * 1 Thread 0x7ffff7fd5780 (LWP 1543) "main" main () at main.cpp:21 (gdb) thread 2 switch to thread 2 [Switching to thread 2 (Thread 0x7ffff6fd6700 (LWP 1544))] (gdb) info threads get information about current threads Id Target Id Frame * 2 Thread 0x7ffff6fd6700 (LWP 1544) "main" GI nptl_death_event () at events.c:31 1 Thread 0x7ffff7fd5780 (LWP 1543) "main" main () at main.cpp:21 * indicates we are controlling thread 2 currently
15 Valgrind Debugging and Profiling Tool Makes program faster and performs correctness checks Checks for : Thread Errors helgrind Memory Related Errors, Memory leaks : memcheck
16 Valgrind Open-source debugging tool Install on your laptop using standard OS commands Ubuntu : sudo apt-get install valgrind Compile with -g flag gcc -g main.cpp -o main In A2: make gdb=1
17 Valgrind - Detecting Thread Errors int x = 0; void foo() { x++; } void bar() { x--; } int main() { x = 0; thread t1(foo); thread t2(bar); t1.join(); t2.join(); return 0; }
18 Valgrind - Detecting Thread Errors int x = 0; void foo() { x++; } void bar() { x--; } int main() { x = 0; thread t1(foo); thread t2(bar); t1.join(); t2.join(); return 0; } $ g++ -g main.cpp -o main -std=c++11 -pthread $ valgrind --tool=helgrind./main. Possible data race during read of size 4 at 0x6042BC by thread #1 ==1085== Locks held: none ==1085== at 0x400F4C: main (main.cpp:20) ==1085== ==1085== This conflicts with a previous write of size 4 by thread #3 ==1085== Locks held: none ==1085== at 0x400F0F: bar() (main.cpp:12) ==1085==..
19 Valgrind - Detecting Memory Leaks Memcheck can detect: Use of uninitialised memory Reading/writing memory after it has been free'd Reading/writing off the end of malloc'd blocks Reading/writing inappropriate areas on the stack Memory leaks -- where pointers to malloc'd blocks are lost forever Mismatched use of malloc/new/new [] vs free/delete/delete [] Overlapping src and dst pointers in memcpy() and related functions Some misuses of the POSIX pthreads API
20 Valgrind - Detecting Memory Leaks #include <stdio.h> int main() { char *p; // Allocation #1 of 19 bytes p = (char *) malloc(19); // Allocation #2 of 12 bytes p = (char *) malloc(12); free(p); $gcc -o test -g test.c $valgrind --tool=memcheck --leak-check=yes --show-reachable=yes --num-callers=20 --track-fds=yes./test // Allocation #3 of 16 bytes p = (char *) malloc(16); return 0; }
21 Valgrind - Detecting Memory Leaks $gcc -o test -g test.c $valgrind --tool=memcheck --leak-check=yes --show-reachable=yes --num-callers=20 --track-fds=yes./test Output: ==9704== Memcheck, a memory error detector for x86-linux. ==9704== Copyright (C) , and GNU GPL'd, by Julian Seward et al. ==9704== Using valgrind-2.2.0, a program supervision framework for x86-linux. ==9704== Copyright (C) , and GNU GPL'd, by Julian Seward et al. ==9704== For more details, rerun with: -v ==9704== ==9704== ==9704== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 11 from 1) ==9704== malloc/free: in use at exit: 35 bytes in 2 blocks. ==9704== malloc/free: 3 allocs, 1 frees, 47 bytes allocated. ==9704== For counts of detected errors, rerun with: -v ==9704== searching for pointers to 2 not-freed blocks. ==9704== checked bytes. ==9704== ==9704== 16 bytes in 1 blocks are definitely lost in loss record 1 of 2 ==9704== at 0x1B903D38: malloc (vg_replace_malloc.c:131) ==9704== by 0x80483BF: main (test.c:15) ==9704== ==9704== ==9704== 19 bytes in 1 blocks are definitely lost in loss record 2 of 2 ==9704== at 0x1B903D38: malloc (vg_replace_malloc.c:131) ==9704== by 0x : main (test.c:8) ==9704== ==9704== LEAK SUMMARY: ==9704== definitely lost: 35 bytes in 2 blocks. ==9704== possibly lost: 0 bytes in 0 blocks. ==9704== still reachable: 0 bytes in 0 blocks. ==9704== suppressed: 0 bytes in 0 blocks.
22 Other uses of Valgrind Cachegrind Cache profiling Callgrind Call-graph generation Can be used for Deadlock detection DRD - Another thread error detection tool under Valgrind Link for DRD info Memcheck is not perfect. Occasionally produces False Positives 99% of time correct
Use Dynamic Analysis Tools on Linux
Use Dynamic Analysis Tools on Linux FTF-SDS-F0407 Gene Fortanely Freescale Software Engineer Catalin Udma A P R. 2 0 1 4 Software Engineer, Digital Networking TM External Use Session Introduction This
More informationCSCI-1200 Data Structures Spring 2016 Lecture 6 Pointers & Dynamic Memory
Announcements CSCI-1200 Data Structures Spring 2016 Lecture 6 Pointers & Dynamic Memory There will be no lecture on Tuesday, Feb. 16. Prof. Thompson s office hours are canceled for Monday, Feb. 15. Prof.
More informationDEBUGGING: DYNAMIC PROGRAM ANALYSIS
DEBUGGING: DYNAMIC PROGRAM ANALYSIS WS 2017/2018 Martina Seidl Institute for Formal Models and Verification System Invariants properties of a program must hold over the entire run: integrity of data no
More informationCSCI-1200 Data Structures Spring 2013 Lecture 7 Templated Classes & Vector Implementation
CSCI-1200 Data Structures Spring 2013 Lecture 7 Templated Classes & Vector Implementation Review from Lectures 5 & 6 Arrays and pointers Different types of memory ( automatic, static, dynamic) Dynamic
More informationCSCI-1200 Data Structures Fall 2015 Lecture 6 Pointers & Dynamic Memory
CSCI-1200 Data Structures Fall 2015 Lecture 6 Pointers & Dynamic Memory Announcements: Test 1 Information Test 1 will be held Monday, September 21st, 2015 from 6-:50pm. Students have been randomly assigned
More informationC++ development tools for Linux
C++ development tools for Linux Jesper K. Pedersen Copyright 2004 Jesper K. Pedersen Table of Contents Tools in general... 1 Advanced Development Tools... 6 Tools
More informationThe Valgrind Memory Checker. (i.e., Your best friend.)
The Valgrind Memory Checker. (i.e., Your best friend.) Dept of Computing Science University of Alberta Small modifications by Stef Nychka, Mar. 2006 5th March 2006 Attribution. Introduction Some of the
More informationValgrind. Philip Blakely. Laboratory for Scientific Computing, University of Cambridge. Philip Blakely (LSC) Valgrind 1 / 21
Valgrind Philip Blakely Laboratory for Scientific Computing, University of Cambridge Philip Blakely (LSC) Valgrind 1 / 21 Part I Valgrind Philip Blakely (LSC) Valgrind 2 / 21 Valgrind http://valgrind.org/
More informationvalgrind overview: runtime memory checker and a bit more What can we do with it?
Valgrind overview: Runtime memory checker and a bit more... What can we do with it? MLUG Mar 30, 2013 The problem When do we start thinking of weird bug in a program? The problem When do we start thinking
More informationData and File Structures Laboratory
Tools: GDB, Valgrind Assistant Professor Machine Intelligence Unit Indian Statistical Institute, Kolkata August, 2018 1 GDB 2 Valgrind A programmer s experience Case I int x = 10, y = 25; x = x++ + y++;
More informationCSE 374 Final Exam 3/15/17. Name UW ID#
Name UW ID# There are 10 questions worth a total of 110 points. Please budget your time so you get to all of the questions. Keep your answers brief and to the point. The exam is closed book, closed notes,
More informationDebugging (Part 2) 1
Debugging (Part 2) 1 Programming in the Large Steps Design & Implement Program & programming style (done) Common data structures and algorithms Modularity Building techniques & tools (done) Test Testing
More informationCS2141 Software Development using C/C++ Debugging
CS2141 Software Development using C/C++ Debugging Debugging Tips Examine the most recent change Error likely in, or exposed by, code most recently added Developing code incrementally and testing along
More informationICHEC. Using Valgrind. Using Valgrind :: detecting memory errors. Introduction. Program Compilation TECHNICAL REPORT
ICHEC TECHNICAL REPORT Mr. Ivan Girotto ICHEC Computational Scientist Stoney Compute Node Bull Novascale R422-E2 Using Valgrind :: detecting memory errors Valgrind is a suite of command line tools both
More informationCSE 374 Final Exam 3/15/17 Sample Solution. Question 1. (8 points) Suppose we have the following two statements in a C program:
Question 1. (8 points) Suppose we have the following two statements in a C program: int *x = malloc(sizeof(int)); int *y = malloc(sizeof(int)); For each of the following expressions, write true if the
More informationCS168: Debugging. Introduc)on to GDB, Wireshark and Valgrind. CS168 - Debugging Helpsession
CS168: Debugging Introduc)on to GDB, Wireshark and Valgrind GDB: The GNU Debugger gdb is an executable file that serves as a portable debugger Works for Ada, C, C++, Objec)ve- C, Pascal, and others Useful
More informationKey C Topics: Tutorial Pointers, Dynamic Memory allocation, Valgrind and Makefile CS370
Key C Topics: Tutorial Pointers, Dynamic Memory allocation, Valgrind and Makefile CS370 Outline Pointers in C & and * operators Pointers with Arrays and Strings Dynamic memory allocation malloc() and free()
More informationThe Valgrind Memory Checker. (i.e., Your best friend.)
The Valgrind Memory Checker. (i.e., Your best friend.) Dept of Computing Science University of Alberta modifications by Stef Nychka October 24, 2007 Attribution. Introduction Some of the material in this
More informationMemory Allocation in C C Programming and Software Tools. N.C. State Department of Computer Science
Memory Allocation in C C Programming and Software Tools N.C. State Department of Computer Science The Easy Way Java (JVM) automatically allocates and reclaims memory for you, e.g... Removed object is implicitly
More information6.S096: Introduction to C/C++
6.S096: Introduction to C/C++ Frank Li, Tom Lieber, Kyle Murray Lecture 4: Data Structures and Debugging! January 17, 2012 Today Memory Leaks and Valgrind Tool Structs and Unions Opaque Types Enum and
More informationPraktische Aspekte der Informatik
Praktische Aspekte der Informatik Moritz Mühlhausen Prof. Marcus Magnor Optimization valgrind, gprof, and callgrind Further Reading Warning! The following slides are meant to give you a very superficial
More informationPrinceton University Computer Science 217: Introduction to Programming Systems. Data Structures
Princeton University Computer Science 217: Introduction to Programming Systems Data Structures 1 Goals of this Lecture Help you learn (or refresh your memory) about: Common data structures: linked lists
More informationMemory Analysis tools
Memory Analysis tools PURIFY The Necessity TOOL Application behaviour: Crashes intermittently Uses too much memory Runs too slowly Isn t well tested Is about to ship You need something See what your code
More informationScientific Programming in C IX. Debugging
Scientific Programming in C IX. Debugging Susi Lehtola 13 November 2012 Debugging Quite often you spend an hour to write a code, and then two hours debugging why it doesn t work properly. Scientific Programming
More informationDebugging. Marcelo Ponce SciNet HPC Consortium University of Toronto. July 15, /41 Ontario HPC Summerschool 2016 Central Edition: Toronto
Debugging Marcelo Ponce SciNet HPC Consortium University of Toronto July 15, 2016 1/41 Ontario HPC Summerschool 2016 Central Edition: Toronto Outline Debugging Basics Debugging with the command line: GDB
More informationThe assignment requires solving a matrix access problem using only pointers to access the array elements, and introduces the use of struct data types.
C Programming Simple Array Processing The assignment requires solving a matrix access problem using only pointers to access the array elements, and introduces the use of struct data types. Both parts center
More informationBoth parts center on the concept of a "mesa", and make use of the following data type:
C Programming Simple Array Processing This assignment consists of two parts. The first part focuses on array read accesses and computational logic. The second part requires solving the same problem using
More informationProjet 0 - Correc,on. Structures de données et algorithmes
Projet 0 - Correc,on Structures de données et algorithmes Code de base #include #define uint unsigned int #define N 101 int f(int m, int M, uint* s) *s ^= (uint)(*s
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 informationPointers. Héctor Menéndez 1. November 28, AIDA Research Group Computer Science Department Universidad Autónoma de Madrid.
Pointers Héctor Menéndez 1 AIDA Research Group Computer Science Department Universidad Autónoma de Madrid November 28, 2013 1 based on the original slides of the subject Index 1 Dynamic Memory 2 Arrays
More informationProgramming Studio #9 ECE 190
Programming Studio #9 ECE 190 Programming Studio #9 Concepts: Functions review 2D Arrays GDB Announcements EXAM 3 CONFLICT REQUESTS, ON COMPASS, DUE THIS MONDAY 5PM. NO EXTENSIONS, NO EXCEPTIONS. Functions
More informationPointers and Memory Management
Pointers and Memory Management Timo Karvi 2013 Timo Karvi () Pointers and Memory Management 2013 1 / 58 Memory and C I In most modern computers, main memory is divided into bytes, with each byte capable
More informationCSE 333 Midterm Exam Sample Solution 7/28/14
Question 1. (20 points) C programming. For this question implement a C function contains that returns 1 (true) if a given C string appears as a substring of another C string starting at a given position.
More informationCptS 360 (System Programming) Unit 4: Debugging
CptS 360 (System Programming) Unit 4: Debugging Bob Lewis School of Engineering and Applied Sciences Washington State University Spring, 2018 Motivation You re probably going to spend most of your code
More informationKDev-Valgrind : User Documentation
KDev-Valgrind : User Documentation Damien Coppel Anthony Corbacho Lionel Duc Mathieu Lornac Sébastien Rannou Lucas Sarie This document is for developers wishing to use the plugin. It enables to understand
More informationA Capacity: 10 Usage: 4 Data:
Creating a Data Type in C Integer Set For this assignment, you will use the struct mechanism in C to implement a data type that represents sets of integers. A set can be modeled using the C struct: struct
More informationScientific Programming in C IV. Pointers
Scientific Programming in C IV. Pointers Susi Lehtola 1 November 2012 Pointers The feature at the heart of C are pointers, which are simply pointers to memory addresses. Scientific Programming in C, fall
More informationValgrind Documentation
Valgrind Documentation Release 3.10.0 10 September 2014 Copyright 2000-2014 AUTHORS Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License,
More informationEE355 Lab 5 - The Files Are *In* the Computer
1 Introduction In this lab you will modify a working word scramble game that selects a word from a predefined word bank to support a user-defined word bank that is read in from a file. This is a peer evaluated
More informationValgrind Documentation
.eps Valgrind Documentation Release 3.13.0 15 June 2017 Copyright 2000-2017 AUTHORS Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License,
More informationParallelization Primer. by Christian Bienia March 05, 2007
Parallelization Primer by Christian Bienia March 05, 2007 What is Parallelization? Answer: The creation of a new algorithm! Trivial case: Run sequential algorithm on multiple CPUs, throw locks around shared
More informationValgrind Documentation
Valgrind Documentation Release 3.6.0 21 October 2010 Copyright 2000-2010 AUTHORS Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License,
More informationLecture 14 Notes. Brent Edmunds
Lecture 14 Notes Brent Edmunds October 5, 2012 Table of Contents 1 Sins of Coding 3 1.1 Accessing Undeclared Variables and Pointers...................... 3 1.2 Playing With What Isn t Yours..............................
More informationCMSC 341 Lecture 2 Dynamic Memory and Pointers
CMSC 341 Lecture 2 Dynamic Memory and Pointers Park Sects. 01 & 02 Based on earlier course slides at UMBC Today s Topics Stack vs Heap Allocating and freeing memory new and delete Memory Leaks Valgrind
More informationCore dumped - on debuggers and other tools
Pascal M. Vaudrevange 28.03.2008 1 2 3 4 5 Motto Everyone knows that debugging is twice as hard as writing a program in the first place. So if you re as clever as you can be when you write it, how will
More informationDebugging with GDB and DDT
Debugging with GDB and DDT Ramses van Zon SciNet HPC Consortium University of Toronto June 13, 2014 1/41 Ontario HPC Summerschool 2014 Central Edition: Toronto Outline Debugging Basics Debugging with the
More informationDebugging with GDB and DDT
Debugging with GDB and DDT Ramses van Zon SciNet HPC Consortium University of Toronto June 28, 2012 1/41 Ontario HPC Summerschool 2012 Central Edition: Toronto Outline Debugging Basics Debugging with the
More informationProgramming Tips for CS758/858
Programming Tips for CS758/858 January 28, 2016 1 Introduction The programming assignments for CS758/858 will all be done in C. If you are not very familiar with the C programming language we recommend
More informationIntermediate Programming, Spring 2017*
600.120 Intermediate Programming, Spring 2017* Misha Kazhdan *Much of the code in these examples is not commented because it would otherwise not fit on the slides. This is bad coding practice in general
More informationPerformance Measurement
ECPE 170 Jeff Shafer University of the Pacific Performance Measurement 2 Lab Schedule Activities Today / Thursday Background discussion Lab 5 Performance Measurement Next Week Lab 6 Performance Optimization
More informationCSci 4061 Introduction to Operating Systems. Programs in C/Unix
CSci 4061 Introduction to Operating Systems Programs in C/Unix Today Basic C programming Follow on to recitation Structure of a C program A C program consists of a collection of C functions, structs, arrays,
More informationCS105 C++ Lecture 7. More on Classes, Inheritance
CS105 C++ Lecture 7 More on Classes, Inheritance " Operator Overloading Global vs Member Functions Difference: member functions already have this as an argument implicitly, global has to take another parameter.
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 informationDevelopment in code_aster Debugging a code_aster execution
Development in code_aster Debugging a code_aster execution Code_Aster, Salome-Meca course material GNU FDL licence (http://www.gnu.org/copyleft/fdl.html) How to debug a code_aster execution? Requirements
More informationMemory and Arrays. CSE 333 Spring Instructor: Justin Hsia
Memory and Arrays CSE 333 Spring 2018 Instructor: Justin Hsia Teaching Assistants: Danny Allen Dennis Shao Eddie Huang Kevin Bi Jack Xu Matthew Neldam Michael Poulain Renshu Gu Robby Marver Waylon Huang
More informationDebugging with gdb and valgrind
Debugging with gdb and valgrind Dr. Axel Kohlmeyer Associate Dean for Scientific Computing, CST Associate Director, Institute for Computational Science Assistant Vice President for High-Performance Computing
More informationProblem Set 1: Unix Commands 1
Problem Set 1: Unix Commands 1 WARNING: IF YOU DO NOT FIND THIS PROBLEM SET TRIVIAL, I WOULD NOT RECOMMEND YOU TAKE THIS OFFERING OF 300 AS YOU DO NOT POSSESS THE REQUISITE BACKGROUND TO PASS THE COURSE.
More informationPointer Accesses to Memory and Bitwise Manipulation
C Programming Pointer Accesses to Memory and Bitwise Manipulation This assignment consists of implementing a function that can be executed in two modes, controlled by a switch specified by a parameter
More informationCSE 374 Programming Concepts & Tools. Brandon Myers Winter 2015 Lecture 11 gdb and Debugging (Thanks to Hal Perkins)
CSE 374 Programming Concepts & Tools Brandon Myers Winter 2015 Lecture 11 gdb and Debugging (Thanks to Hal Perkins) Hacker tool of the week (tags) Problem: I want to find the definition of a function or
More informationValgrind Documentation Release June 2006 Copyright AUTHORS
Valgrind Documentation Release 3.2.0 7 June 2006 Copyright 2000-2006 AUTHORS Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License,
More informationCS 261 Fall Mike Lam, Professor. Threads
CS 261 Fall 2017 Mike Lam, Professor Threads Parallel computing Goal: concurrent or parallel computing Take advantage of multiple hardware units to solve multiple problems simultaneously Motivations: Maintain
More informationDebugging and Profiling
Debugging and Profiling Dr. Axel Kohlmeyer Senior Scientific Computing Expert Information and Telecommunication Section The Abdus Salam International Centre for Theoretical Physics http://sites.google.com/site/akohlmey/
More informationCS 103 Lab The Files are *In* the Computer
CS 103 Lab The Files are *In* the Computer 1 Introduction In this lab you will modify a word scramble game so that instead of using a hardcoded word list, it selects a word from a file. You will learn
More informationAaron Evans 2004 Nov 15
Aaron Evans 2004 Nov 15 Citation Nicholas Nethercote and Julian Seward, Valgrind: A Program Supervision Framework, Electronic Notes in Theoretical Computer Science, Volume 89, Issue 2, October 2003, Pages
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 informationConcurrency, Thread. Dongkun Shin, SKKU
Concurrency, Thread 1 Thread Classic view a single point of execution within a program a single PC where instructions are being fetched from and executed), Multi-threaded program Has more than one point
More informationMaking things work as expected
Making things work as expected System Programming Lab Maksym Planeta Björn Döbel 20.09.2018 Table of Contents Introduction Hands-on Tracing made easy Dynamic intervention Compiler-based helpers The GNU
More informationLet s go straight to some code to show how to fire off a function that runs in a separate thread:
Introduction to C++11 Threads In C++11 a wrapper Thread class is available. However, you still need to have a library that implements the thread class. Visual Studio supports C++11 threads, but some other
More informationHigh Performance Computing and Programming. Performance Analysis
High Performance Computing and Programming Performance Analysis What is performance? Performance is a total effectiveness of a program What are the measures of the performance? execution time FLOPS memory
More informationCSE 374 Programming Concepts & Tools
CSE 374 Programming Concepts & Tools Hal Perkins Fall 2017 Lecture 22 Shared-Memory Concurrency 1 Administrivia HW7 due Thursday night, 11 pm (+ late days if you still have any & want to use them) Course
More informationCS61, Fall 2012 Section 2 Notes
CS61, Fall 2012 Section 2 Notes (Week of 9/24-9/28) 0. Get source code for section [optional] 1: Variable Duration 2: Memory Errors Common Errors with memory and pointers Valgrind + GDB Common Memory Errors
More informationCSE 4/521 Introduction to Operating Systems
CSE 4/521 Introduction to Operating Systems Lecture 5 Threads (Overview, Multicore Programming, Multithreading Models, Thread Libraries, Implicit Threading, Operating- System Examples) Summer 2018 Overview
More informationSingle Processor Optimization III
Russian-German School on High-Performance Computer Systems, 27th June - 6th July, Novosibirsk 2. Day, 28th of June, 2005 HLRS, University of Stuttgart Slide 1 Outline Motivation Valgrind Memory Tracing
More informationC Tutorial. Pointers, Dynamic Memory allocation, Valgrind, Makefile - Abhishek Yeluri and Yashwant Reddy Virupaksha
C Tutorial Pointers, Dynamic Memory allocation, Valgrind, Makefile - Abhishek Yeluri and Yashwant Reddy Virupaksha CS 370 - Operating Systems - Spring 2019 1 Outline What is a pointer? & and * operators
More information0/41. Isolating Infections. Andreas Zeller. Lehrstuhl Softwaretechnik Universität des Saarlandes, Saarbrücken
0/41 Isolating Infections Andreas Zeller Lehrstuhl Softwaretechnik Universität des Saarlandes, Saarbrücken Isolating the Infection 1/41 Variable and input values Program execution Sane state Program states
More informationCS 314 Principles of Programming Languages. Lecture 9
CS 314 Principles of Programming Languages Lecture 9 Zheng Zhang Department of Computer Science Rutgers University Wednesday 5 th October, 2016 Zheng Zhang 1 CS@Rutgers University Class Information Homework
More informationMemory Management. CS449 Fall 2017
Memory Management CS449 Fall 2017 Life9mes Life9me: 9me from which a par9cular memory loca9on is allocated un9l it is deallocated Three types of life9mes Automa9c (within a scope) Sta9c (dura9on of program)
More informationDebugging with TotalView
Debugging with TotalView Le Yan HPC Consultant User Services Goals Learn how to start TotalView on Linux clusters Get familiar with TotalView graphic user interface Learn basic debugging functions of TotalView
More informationMassif-Visualizer. Memory Profiling UI. Milian Wolff Desktop Summit
Massif-Visualizer Memory Profiling UI Milian Wolff mail@milianw.de Desktop Summit 2011 08.08.2011 Agenda 1 Valgrind 2 Massif 3 Massif-Visualizer Milian Massif-Visualizer Desktop Summit Berlin 2/32 1 Valgrind
More informationdbug User Manual Computer Science Department Carnegie Mellon University
dbug User Manual Jiří Šimša Computer Science Department Carnegie Mellon University Contents 1 Motivation 2 2 Overview 2 3 Implementation 3 4 Installation 3 5 Examples 4 5.1 Sequential Example Interactive
More informationo Code, executable, and process o Main memory vs. virtual memory
Goals for Today s Lecture Memory Allocation Prof. David August COS 217 Behind the scenes of running a program o Code, executable, and process o Main memory vs. virtual memory Memory layout for UNIX processes,
More informationThreads. Thread Concept Multithreading Models User & Kernel Threads Pthreads Threads in Solaris, Linux, Windows. 2/13/11 CSE325 - Threads 1
Threads Thread Concept Multithreading Models User & Kernel Threads Pthreads Threads in Solaris, Linux, Windows 2/13/11 CSE325 - Threads 1 Threads The process concept incorporates two abstractions: a virtual
More informationSoftware Analysis Tools
CSCE 790 Introduction to Software Analysis Software Analysis Tools Professor Lisa Luo Fall 2018 Overview Source code CFG generator Binary code analysis Code obfuscation Symbolic Execution Dynamic analysis
More informationCSE au Final Exam December 12, 2018
Question 1. (16 points) C++ STL. A map is a collection of pairs. For this problem, implement a function reverse_map(m) that takes a map m of pairs as input and returns a new map
More informationAgenda Process Concept Process Scheduling Operations on Processes Interprocess Communication 3.2
Lecture 3: Processes Agenda Process Concept Process Scheduling Operations on Processes Interprocess Communication 3.2 Process in General 3.3 Process Concept Process is an active program in execution; process
More informationMemory Checking and Single Processor Optimization with Valgrind [05b]
Memory Checking and Single Processor Optimization with Valgrind Memory Checking and Single Processor Optimization with Valgrind [05b] University of Stuttgart High-Performance Computing-Center Stuttgart
More informationNew features in AddressSanitizer. LLVM developer meeting Nov 7, 2013 Alexey Samsonov, Kostya Serebryany
New features in AddressSanitizer LLVM developer meeting Nov 7, 2013 Alexey Samsonov, Kostya Serebryany Agenda AddressSanitizer (ASan): a quick reminder New features: Initialization-order-fiasco Stack-use-after-scope
More informationTI2725-C, C programming lab, course
Valgrind tutorial Valgrind is a tool which can find memory leaks in your programs, such as buffer overflows and bad memory management. This document will show per example how Valgrind responds to buggy
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 informationPRACE Autumn School Basic Programming Models
PRACE Autumn School 2010 Basic Programming Models Basic Programming Models - Outline Introduction Key concepts Architectures Programming models Programming languages Compilers Operating system & libraries
More informationProfilers and Debuggers. Introductory Material. One-Slide Summary
Profilers and Debuggers #1 Introductory Material First, who doesn t know assembly language? You ll get to answer all the assembly questions. Yes, really. Lecture Style: Sit on the table and pose questions.
More informationCS 333 Introduction to Operating Systems. Class 3 Threads & Concurrency. Jonathan Walpole Computer Science Portland State University
CS 333 Introduction to Operating Systems Class 3 Threads & Concurrency Jonathan Walpole Computer Science Portland State University 1 The Process Concept 2 The Process Concept Process a program in execution
More informationECE 7650 Scalable and Secure Internet Services and Architecture ---- A Systems Perspective. Part I: Operating system overview: Processes and threads
ECE 7650 Scalable and Secure Internet Services and Architecture ---- A Systems Perspective Part I: Operating system overview: Processes and threads 1 Overview Process concept Process scheduling Thread
More informationTuning Valgrind for your Workload
Tuning Valgrind for your Workload Hints, tricks and tips to effectively use Valgrind on small or big applications Philippe Waroquiers FOSDEM 2015 valgrind devroom 1 Some rumours about Valgrind... Valgrind
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 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 information1 A Brief Introduction To GDB
1 A Brief Introduction To GDB GDB, the GNU Project debugger, allows you to see what is going on inside another program while it executes or what another program was doing at the moment it crashed. GDB
More informationCSE 351, Spring 2010 Lab 7: Writing a Dynamic Storage Allocator Due: Thursday May 27, 11:59PM
CSE 351, Spring 2010 Lab 7: Writing a Dynamic Storage Allocator Due: Thursday May 27, 11:59PM 1 Instructions In this lab you will be writing a dynamic storage allocator for C programs, i.e., your own version
More informationEI 338: Computer Systems Engineering (Operating Systems & Computer Architecture)
EI 338: Computer Systems Engineering (Operating Systems & Computer Architecture) Dept. of Computer Science & Engineering Chentao Wu wuct@cs.sjtu.edu.cn Download lectures ftp://public.sjtu.edu.cn User:
More informationDebugging. John Lockman Texas Advanced Computing Center
Debugging John Lockman Texas Advanced Computing Center Debugging Outline GDB Basic use Attaching to a running job DDT Identify MPI problems using Message Queues Catch memory errors PTP For the extremely
More information