chapter03 processes

Chng 3: Tin Trnh

PROCESS

ThS: H L Hoi Trung

2Khoa KTMT

n tp chng 2

H iu hnh c my thnh phn

Phn bit gia sytem call & library

Cu trc h thng.

My o nhim v ca my o

Tin trnh l g? Nhim v chnh ca thnh phn qun l tin

trnh? Cc Tin trnh cng chy 1 chng trnh?

3Khoa KTMT

Mc tiu

Hiu c qu trnh l g?

Cc trng thi ca qu trnh

Cu trc d liu ca Qu trnh

Cch to ra 1 qu trnh. Mi quan h cha con gia cc qu trnh

Cch giao tip gia cc tin trnh

Tiu trnh (Thread)

4Khoa KTMT

Ni Dung

Khai niem c ban

Trang thai qua trnh

Khoi ieu khien qua trnh (Process control block)

nh thi qua trnh (Process Scheduling)

Cac tac vu oi vi qua trnh

S cong tac gia cac qua trnh

Giao tiep gia cac qua trnh

5Khoa KTMT

3.1. Khai niem c ban

Hoat ong cua CPU gi l g?

He thong bo (Batch system): jobs

Time-shared systems: user programs, tasks

Cac hoat ong la tng t => goi la process

Qua trnh (process)

mot chng trnh ang thc thi

Mot qua trnh bao gom

Text section (program code), data section (cha global variables)

program counter (PC), process status word (PSW), stack pointer (SP), memory management registers,

max

0

6Khoa KTMT


Cac bc nap chng trnh vao bo nh

7Khoa KTMT


program

code

data

Executable binary file

(load module)

program

code

data

stack

Process image in

main memory

Dung load module e bieu dien chng trnh thc thi c

Layout luan ly cua process image

start address

chng trnh => qua trnh

8Khoa KTMT


Cac bc he ieu hanh khi tao qua trnh

Cap phat mot nh danh duy nhat (process number hay process identifier, pid) cho qua trnh

Cap phat khong gian nh e nap qua trnh

Khi tao khoi d lieu Process Control Block (PCB) cho qua trnh

PCB la ni he ieu hanh lu cac thong tin ve qua trnh

Thiet lap cac moi lien he can thiet (vd: sap PCB vao hang i nh thi,)

Khi tao qua trnh

9Khoa KTMT

3.2.Trang thai qua trnh

Cac trang thai cua qua trnh (process states):

new: qua trnh va c tao

ready: qua trnh a co u tai nguyen, ch con can CPU

running: cac lenh cua qua trnh ang c thc thi

waiting: hay la blocked, qua trnh i I/O hoan tat, tn hieu.

terminated: qua trnh a ket thuc.

10Khoa KTMT


ready running

dispatch

interrupt

I/O or event

completion

I/O or

event wait

newterminated

waiting

admit exit

Chuyen oi gia cac trang thai cua qua trnh

11Khoa KTMT


/* test.c */

int main(int argc, char** argv)

{

printf(Hello world\n");exit(0);

}

Bien dch chng trnh trong Linux

gcc test.c o test

Thc thi chng trnh test

./test

Trong he thong se co mot qua trnh

test c tao ra, thc thi va ket

thuc.

Chuoi trang thai cua qua

trnh test nh sau (trng

hp tot nhat):

new

ready

running

waiting (do ch I/O khi goi printf)

ready

running

terminated

V du

12Khoa KTMT

V d

Cho on chng trnh nh

sau:

/* test.c */


{

int a = 2 + 3;

exit(0);

}

Bin dch chng trnh trong

Linux

gcc test.c o test

Thc thi chng trnh

/test

Chui trng thi ca

qu trnh test

13Khoa KTMT

V d Cho on chng trnh nh sau:

/* test.c */


{

int a = 2 + 3;

printf(Hello);

printf(Hi);

exit(0);

}

Bin dch chng trnh trong

Linux

gcc test.c o test

Thc thi chng trnh

/test

Chui trng thi

ca qu trnh test

l?

14Khoa KTMT

3.3.Process control block

a thay la moi qua trnh trong he thong eu c cap phat mot

Process Control Block (PCB)

PCB la mot trong cac cau truc d lieu quan

trong nhat cua he ieu hanh va gom:

- Trang thai qua trnh: new, ready, running,- Bo em chng trnh

- Cac thanh ghi

- Thong tin lap thi bieu CPU: o u tien, - Thong tin quan ly bo nh

- Thong tin tai khoan: lng CPU, thi gian s

dung,

- Thong tin trang thai I/O

15Khoa KTMT

Process Representation in Linux

Represented by the C structure task_struct

pid t pid; /* process identifier */

long state; /* state of the process */

unsigned int time slice /* scheduling information */ struct

task struct *parent; /* this processs parent */ struct

list head children; /* this processs children */ struct

files struct *files; /* list of open files */ struct mm

struct *mm; /* address space of this pro */

16Khoa KTMT

3.3.Process control block

Lu o

chuyen CPU

t qua trnh

nay en qua

trnh khac

17Khoa KTMT

Yeu cau oi vi he ieu hanh ve quan ly qua trnh

Ho tr s thc thi luan phien gia nhieu qua trnh

Hieu suat s dung CPU

Thi gian ap ng

Phan phoi tai nguyen he thong hp ly

tranh deadlock, tr hoan vo han nh,

Cung cap c che giao tiep va ong bo hoat ong cac

qua trnh

Cung cap c che ho tr user tao/ket thuc qua trnh

18Khoa KTMT

running

ready

waiting

Quan ly cac qua trnh: cac hang i

7

11 4 2 17

19 11

process number

cac PCB

Co g sai trong v du?

V du

19Khoa KTMT

3.4. nh thi qua trnh (Process Scheduling)

Tai sao phai nh thi?

a chng (Multiprogramming)

Co vai qua trnh chay tai cac thi iem

Muc tieu: tan dung toi a CPU

Chia thi(Time-sharing)

Users tng tac vi moi chng trnh ang thc thi

Muc tieu: toi thieu thi gian ap ng

Mot so khai niem c ban

Cac bo nh thi (scheduler)

Cac hang i nh thi (scheduling queue)

20Khoa KTMT

Cac hang i nh thi (Scheduling queues)

Hang i cong

viec-Job queue

Hang i san

sang-Ready

queue

Hang i thiet

b-Device

queues

21Khoa KTMT

Cac hang i nh thi (Scheduling queues)

Lu o hang i cua nh thi qua trnh

22Khoa KTMT

3.5. Bo nh thi (Scheduler)

Bo nh thi cong viec (Job scheduler) hay bo nh thi

dai (long-term scheduler)

Bo nh thi CPU hay bo nh thi ngan

Cac qua trnh co the mo ta nh:

Qua trnh hng I/O (I/O bound process)

Qua trnh hng CPU (CPU bound process)

Thi gian thc hien khac nhau => ket hp hai hoa gia chung

23Khoa KTMT

Bo nh thi trung gian(medium-term scheduling)

oi khi he ieu hanh (nh time-sharing system) co them

medium-term scheduling e ieu chnh mc o a

chng cua he thong

Medium-term scheduler

chuyen qua trnh t bo nh sang a (swap out)

chuyen qua trnh t a vao bo nh (swap in)

24Khoa KTMT

3.6. Cac tac vu oi vi qua trnh

Tao qua trnh mi (process creation)

Mot qua trnh co the tao nhieu qua trnh mi thong qua mot li goi he thong create-process (vd: ham fork

trong Unix)

V du: (Unix) Khi user ang nhap he thong, mot command interpreter (shell) se c tao ra cho

user

Qua trnh c tao la qua trnh con cua qua trnh tao (qua trnh cha). Quan he cha-con nh ngha mot cay

qua trnh.

Ti nguyn chia s

Thc thi

Khng gian a ch

25Khoa KTMT

Cay qua trnh trong Linux/Unix

V du

26Khoa KTMT

A Tree of Processes on Solaris

27Khoa KTMT

3.6.Cac tac vu oi vi qua trnh

Tao qua trnh mi

Qua trnh con nhan tai nguyen: t HH hoac t P cha

Chia se tai nguyen cua qua trnh cha

Qua trnh cha va con chia se moi tai nguyen

Qua trnh con chia se mot phan tai nguyen cua cha

Trnh t thc thi

Qua trnh cha va con thc thi ong thi (concurrently)

Qua trnh cha i en khi cac qua trnh con ket thuc.

28Khoa KTMT

Ve quan he cha/con

Khong gian a ch (address space)

Khong gian a ch cua qua trnh con c nhan ban t cha

Khong gian a ch cua qua trnh con c khi tao t template.

V du trong UNIX/Linux

System call fork() tao mot qua trnh mi

System call exec() dung sau fork() e nap mot chng trnh mi vao khong gian nh cua qua trnh mi

ong bo

29Khoa KTMT

V du tao process vi fork()

#include

#include

int main (int argc, char *argv[]){

int pid;

/* create a new process */

pid = fork();

if (pid > 0){

printf(This is parent process);

wait(NULL);

exit(0);

}

else if (pid == 0)

{

printf(This is child process);

execlp(/bin/ls, ls, NULL);

exit(0);

}

else {

printf(Fork error\n);

exit(-1);

}

}

30Khoa KTMT

V d

#include

#include

void main(int argc, char *argv[]){

printf (hi);fork ();

printf (Hello);fork ();

printf (Bye);}

Hi chng trnh in ra cc dng ch no trn mn hnh.

31Khoa KTMT

V d

#include

#include

void main(int argc, char *argv[]) {

int pid; 1

printf (hi); 2

pid = fork (); 3

If( pid == 0) { 4

fork (); 5

printf (Hello); 6

} else 7

printf (Bye); 8

}

Hi chng trnh in ra cc dng ch no trn mn hnh.

B lnh dng 4, dng 7. Chng trnh in ra cc dng ch no.

32Khoa KTMT

3.6.Cac tac vu oi vi qua trnh (tt)

Tao qua trnh mi

Ket thuc qua trnh

Qua trnh t ket thuc

Qua trnh ket thuc khi thc thi lenh cuoi va goi system routine

exit

Qua trnh ket thuc do qua trnh khac (co u quyen, vd: qua trnh

cha cua no)

Goi system routine abort vi tham so la pid (process identifier)

cua qua trnh can c ket thuc

He ieu hanh thu hoi tat ca cac tai nguyen cua qua trnh ket

thuc (vung nh, I/O buffer,)

33Khoa KTMT

3.7. Cong tac gia cac qua trnh

Trong qua trnh thc thi, cac qua trnh co the cong tac

(cooperate) e hoan thanh cong viec

Cac qua trnh cong tac e

Chia se d lieu (information sharing)

Tang toc tnh toan (computational speedup)

Neu he thong co nhieu CPU, chia cong viec tnh toan thanh nhieu cong viec tnh toan nho chay song song

Thc hien mot cong viec chung

Xay dng mot phan mem phc tap bang cach chia thanh cac module/process hp tac nhau

S cong tac gia cac qua trnh yeu cau he ieu hanh ho

tr c che giao tiep va c che ong bo hoat ong cua

cac qua trnh

34Khoa KTMT

Bai toan ngi san xuat-ngi tieu thu

(producer-consumer )

V du cong tac gia cac qua trnh: bai toan producer-

consumer

Producer tao ra cac d lieu va consumer tieu thu, s dung cac d lieu o. S trao oi thong tin thc hien qua buffer

unbounded buffer: kch thc buffer vo han (khong thc te).

bounded buffer: kch thc buffer co han.

Producer va consumer phai hoat ong ong bo v

Consumer khong c tieu thu khi producer cha san xuat

Producer khong c tao them san pham khi buffer ay.

35Khoa KTMT

Hin thc

#define BUFFER_SIZE 10

typedef struct {

. . .

} item;

item buffer[BUFFER_SIZE];

int in = 0;

int out = 0;

36Khoa KTMT

Hin thc

while (true) {

/* Produce an item */

while (((in = (in + 1) % BUFFER SIZE count) == out)

; /* do nothing -- no free buffers */

buffer[in] = item;

in = (in + 1) % BUFFER SIZE;

}

37Khoa KTMT

Hin thc

while (true) {

while (in == out)

; // do nothing -- nothing to consume

// remove an item from the buffer

item = buffer[out];

out = (out + 1) % BUFFER SIZE;

return item;

}

38Khoa KTMT

3.8.Giao tiep lien qua trnh (Interprocess

communication-IPC)

IPC la c che cung cap bi he ieu hanh nham giup cac

qua trnh

giao tiep vi nhau

va ong bo hoat ong

ma khong can chia se khong gian a ch

IPC co the c cung cap bi message passing system

39Khoa KTMT

He thong truyen thong iep

Message passing system

Lam the nao e cac qua trnh giao tiep nhau? Cac van e:

at ten (Naming)

Giao tiep trc tiep

send(P, msg): gi thong iep en qua trnh P

receive(Q, msg): nhan thong iep en t qua trnh Q

Giao tiep gian tiep: thong qua mailbox hay port

send(A, msg): gi thong iep en mailbox A

receive(B, msg): nhan thong iep t mailbox B

ong bo hoa (Synchronization): blocking send, nonblocking send,

blocking receive, nonblocking receive

Tao vung em (Buffering): dung queue e tam cha cac message

Kha nang cha la 0(Zero capacity hay no buffering)

Bounded capacity: o dai cua queue la gii han

Unbounded capacity: o dai cua queue la khong gii han

40Khoa KTMT

Comunication Client server

Socket

Remote procedure calls

Pipes

41Khoa KTMT

Tieu trnh (luong) - Thread

Tieu trnh(tien trnh nhe-lightweight process): la mot n

v c ban s dung CPU, gom:

Thread ID, PC, Registers, stack va chia se chung code, data, resources (files)

42Khoa KTMT

ng dng

43Khoa KTMT

PCB vaTCB trong mo hnh multithreads

pid

Threads list

Context

(Mem, global ressources)

Scheduling statistic

Relatives

( Dad, children)

PCB

tid

State

(State, details)

Context

(IP, local stack)

Thread Control BlockTCB

44Khoa KTMT

Li ch cua tien trnh a luong

ap ng nhanh: Cho phep chng trnh tiep tuc thc thi

khi mot bo phan b khoa hoac mot hoat ong dai

Chia se tai nguyen: tiet kiem khong gian nh

Kinh te: tao va chuyen ng canh nhanh hn tien trnh

VD: trong Solaris 2, tao process cham hn 30 lan,

chuyen cham hn 5 lan

Trong multiprocessor: co the thc hien song song

45Khoa KTMT

Tieu trnh ngi dung (User thread)

Khi nim tiu trnh c h tr bi mt th vin hot ng trong

user mode

T1

Kernel

T2User

mode

Kernel

mode

T3

LWP1 LWP2

P1 P2

46Khoa KTMT

Tiu trnh ht nhan(Kernel thread)

Khi nim tiu trnh c xy dng bn trong ht nhn

T1 T2

HDH

System call

User mode

Kernel mode

47Khoa KTMT

Bi tp

C bao nhiu process c to ra trong on chng

trnh sau:

48Khoa KTMT

Bi tp

Xc nh gi tr pid ca dng A, B, C, D. Bit pid ca process cha

v con l 2600, v 2603

V process tree

49Khoa KTMT

Bi tp

Xc nh gi tr X&Y

V process tree

50Khoa KTMT

Bi tp thc hnh

chapter03 processes

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