3 Higher-Level Synchronization Comp Sci 143 A Spring

3. Higher-Level Synchronization Comp. Sci 143 A Spring, 2013 1

Comp. Sci 143 A Spring, 2013 2

Motivation Comp. Sci 143 A Spring, 2013 3

Monitors Comp. Sci 143 A Spring, 2013 4

Monitors Comp. Sci 143 A Spring, 2013 5

Monitors Comp. Sci 143 A Spring, 2013 6

Monitors Comp. Sci 143 A Spring, 2013 7

Hoare Monitors Comp. Sci 143 A Spring, 2013 8

Hoare Monitors Comp. Sci 143 A Spring, 2013 9

Bounded buffer problem Comp. Sci 143 A Spring, 2013 10

deposit(char data) { if (full. Count==n) notfull. wait; buffer[nextin] = data; nextin = (nextin+1) % n; full. Count = full. Count+1; notempty. signal; } remove(char data) { if (full. Count==0) notempty. wait; data = buffer[nextout]; nextout = (nextout+1) % n; full. Count = full. Count - 1; notfull. signal; } Comp. Sci 143 A Spring, 2013 11

Priority waits Comp. Sci 143 A Spring, 2013 12

Example: alarm clock Comp. Sci 143 A Spring, 2013 13

Example: alarm clock monitor Alarm. Clock { int now=0; condition wakeup; } wake. Me(int n) { int alarm; alarm = now + n; while (now

Example: alarm clock Comp. Sci 143 A Spring, 2013 15

Mesa-style monitors Comp. Sci 143 A Spring, 2013 16

Mesa monitors Comp. Sci 143 A Spring, 2013 17

Monitors in Java Comp. Sci 143 A Spring, 2013 18

Comp. Sci 143 A Spring, 2013 19

Protected types (Ada 95) Comp. Sci 143 A Spring, 2013 20

Example entry deposit(char c) when (full. Count < n) { buffer[nextin] = c; nextin = (nextin + 1) % n; full. Count = full. Count + 1; } entry remove(char c) when (full. Count > 0) { c = buffer[nextout]; nextout = (nextout + 1) % n; full. Count = full. Count - 1; } Comp. Sci 143 A Spring, 2013 21

Comp. Sci 143 A Spring, 2013 22

Distributed Synchronization Comp. Sci 143 A Spring, 2013 23

Distributed Synchronization Comp. Sci 143 A Spring, 2013 24

Types of send/receive Comp. Sci 143 A Spring, 2013 25

Channels, Ports, and Mailboxes Comp. Sci 143 A Spring, 2013 26

Named Message Channels Comp. Sci 143 A Spring, 2013 27

Comp. Sci 143 A Spring, 2013 28

Example: Bounded buffer with CSP Comp. Sci 143 A Spring, 2013 29

Bounded Buffer with CSP Comp. Sci 143 A Spring, 2013 30

Bounded buffer with CSP process Bounded. Buffer {. . . while (1) { when ((full. Count0) && receive(request)) { send(remove, buf[nextout]); nextout = (nextout + 1) % n; full. Count = full. Count - 1; } } Comp. Sci 143 A Spring, 2013 31

Ports and Mailboxes Comp. Sci 143 A Spring, 2013 32

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Comp. Sci 143 A Spring, 2013 34

Procedure-Based Communication Comp. Sci 143 A Spring, 2013 35

RPC Comp. Sci 143 A Spring, 2013 36

Rendezvous Comp. Sci 143 A Spring, 2013 37

Rendezvous (Ada 95) Comp. Sci 143 A Spring, 2013 38

Comp. Sci 143 A Spring, 2013 39

Rendezvous Comp. Sci 143 A Spring, 2013 40

Example: Bounded Buffer Comp. Sci 143 A Spring, 2013 41

Distributed Mutual Exclusion Comp. Sci 143 A Spring, 2013 42

Distributed Mutual Exclusion Comp. Sci 143 A Spring, 2013 43

Distributed Mutual Exclusion Comp. Sci 143 A Spring, 2013 44

Comp. Sci 143 A Spring, 2013 45

Distributed Mutual Exclusion Comp. Sci 143 A Spring, 2013 46

Comp. Sci 143 A Spring, 2013 47

Readers/Writers Problem Comp. Sci 143 A Spring, 2013 48

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Readers/Writers Problem Comp. Sci 143 A Spring, 2013 50

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Comp. Sci 143 A Spring, 2013 52

Dining philosophers problem Comp. Sci 143 A Spring, 2013 53

Dining Philosophers Comp. Sci 143 A Spring, 2013 54

Dining Philosophers Comp. Sci 143 A Spring, 2013 55

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Comp. Sci 143 A Spring, 2013 57

Elevator algorithm Comp. Sci 143 A Spring, 2013 58

Elevator algorithm Comp. Sci 143 A Spring, 2013 59

Logical Clocks Comp. Sci 143 A Spring, 2013 60

Skewed Physical Clocks Comp. Sci 143 A Spring, 2013 61

Logical Clocks Comp. Sci 143 A Spring, 2013 62

Logical Clocks Comp. Sci 143 A Spring, 2013 63

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