hpc lecture11

7/27/2019 HPC Lecture11

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High Performance Computing

Lecture 11

Matthew Jacob

Indian Institute of Science


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Agenda1. Program execution: Compilation, Object files, Function call

and return, Address space, Data & its representation (4)2. Computer organization: Memory, Registers, Instruction set

architecture, Instruction processing (6)

3. Virtual memory: Address translation, Paging (4)

4. Operating system: Processes, System calls,Process management (6)

5. Pipelined processors: Structural, data and control hazards,impact on programming (4)

6. Cache memory: Organization, impact on programming (5)

7. Program profiling (2)

8. File systems: Disk management, Name management,

Protection (4)9. Parallel programming: Inter-process communication,

Synchronization, Mutual exclusion, Parallel architecture,Programming with message passing using MPI (5)


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Computer Organization: Hardware

CacheMemory

I/O

Bus

I/OI/O

MMU

ALU Registers

CPU

Control


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Computer Organization: Software

Hardware resources of computer system are

shared by programs in execution

Operating System: Special software that

manages this sharing


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Operating Systems (OS)

Examples

Unix

Linux

Apple Mac OS Microsoft Windows

Google Chrome OS

AIX, HP-UX, Solaris

Fedora, openSUSE, Ubuntu, Debian

Mac OS X Snow LeopardWindows 7, Vista, XP


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manages this sharing Process: A program in execution

i.e., present in main memory and being executed

On Unix systems, you can use ps to get

information about the current status of processes

% ps

Shell prompt


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manages this sharing Process: A program in execution

Shell: A command interpreter, through which

you interact with the computer system

Examples of Unix shells: csh, bash

A program; just another program


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% ps

PID TTY TIME CMD

15459 pts/10 00:00:00 bash

15491 pts/10 00:00:00 ps


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% ps -a

PID TTY TIME CMD

6358 pts/4 00:00:00 pine15538 pts/10 00:00:00 ps

20252 pts/2 00:00:01 pine

31066 pts/5 00:00:01 emacs-x

31072 pts/5 00:00:00 xterm

31084 pts/5 00:00:00 xdvi-xaw3d.bin

% ps -l

F S UID PID PPID C PRI NI ADDR SZ WCHAN TTY TIME CMD

0 S 539 15459 15458 0 76 0 - 16517 wait pts/10 00:00:00 bash

0 R 539 15539 15459 0 78 0 - 15876 - pts/10 00:00:00 ps


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Cache

Memory

I/O

Bus

I/OI/O

MMU

ALU Registers

CPU

Control

Operating System, Processes, Hardware


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Hardware

Processes

System Calls

Operating System


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Hardware

Processes

System Calls

OS Kernel


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System Calls

How a process gets the operating system todo something for it

Interface or API (Application Programming

Interface) for interaction with the operating system


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System Calls




Examples: Operations on files creat(): to create a new file

unlink(): to remove a file

open(): to open a file for reading and/or writing

read(): to read data from an open file into a variable

write(): to write data into an open file

lseek(): to change the current pointer into the open file


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System Calls




Examples: Operations on processes fork(): to create a new process

Terminology: parent process calls fork() which

causes a child process to be created

Both parent and child processes continue toexecute from that point in the program


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System Calls





exec(): to change the memory image of a process

e,g, to change the program that a process is

executing


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fork( ) and exec( )

text

data

heap

stack

Parent Process Child Process

text

data

heap

stack

retval = fork();if (retval == 0) {

/* child */

} else {/* parent */

}

exec();


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text

data

heap

stack

text

data

text

Parent Process Child Process

stack

fork( ) and exec( )


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System Calls





exec(): to change the memory image of a process

exit(): to terminate

wait(): to make parent sleep until child terminates


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System Calls




Examples: Operations on memory sbrk: can be used by malloc() to increase size of

the heap


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System Calls




Examples: Operations on files, processes,memory, etc

When a process is executing in a system call,

it is actually executing Operating System

code


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Hardware

Processes

System Calls

Operating System

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