CSS490 M++ Textbook No Corresponding Chapter

Winter, 2004 CSS490 M++ 1

CSS490 M++CSS490 M++Textbook No Corresponding ChapterTextbook No Corresponding Chapter

Instructor: Munehiro Fukuda

These slides were thoroughly the instructor’s original materials.


Thread Migrationoverview

Moving: CPU status Stack (Heap)

LAN/SAN

Distributed Shared Memory (in most cases)

Local memory Local memory Local memory

Migrating a thread

Memory accessMemory access

Actual memoryaccess with high latency


Thread MigrationExamples

System models

Examples Remark

SMP Active threads Migrating threads to a different processor of SMP for dynamic load balancing

DSM Olden, Nomadic threads

Dispatching threads to a remote site close to data they access

Message Passing

uPVM, Ariadne, PM2 Injecting threads to another process for dynamic load balancing

Remote Execution

Nexus Sending a function/arguments with a thread to a remote for remote execution


M++ Mobile Agents

Merits: Inherent parallelism and multi-agent-base applications Demerit: Performance problem because of their

interpretation Thread Migration

Merit: Fast migration Demerits:DSM needed and No navigational autonomy

Logical Network Global application-specific network Constructed at run time Node data referred to after migrating that node.

Extension of C++ Language Agent encapsulated by object-oriented language Navigational autonomy with strong migration


Multi-Agent ApproachSimulate the interaction among agents

Advantages: Overcomes the limitations of

mathematical techniques Encapsulates simulation

models Allows open-ended simulation

Disadvantages: Performance Parallel programming


Parallelizing Multi-Agent Application with MPI

MPI Process must maintain each agent

as a static object maintain as a

simulation space a two-dimensional array

change each status periodically

exchange them with remote processes

Synchronize with remote processes

LAN/SAN

Process 1

Object Queue

Obj 6

Obj 5

Obj 4

Obj 3

Obj 2

Obj 1

null

Object Queue

Obj 6

Obj 5

Obj 4

Obj 3

Obj 2

Obj 1

nullObj 7

Process 2

Exchange


Parallelizing Multi-Agent Application with Mobile Agent

We don’t need a control process!

Each simulation entity works independently as an agent.

LAN/SAN

agent Shark { Shark( ) { … } void run( ) { while (alive) { compute( ); go( ); } }}


Performance Problem Mobile Agents:

They were cognitive agents designed to perform large remote jobs.

They are code in Java and Tcl, and thus interpreted.

Their size is so big and their speed is so slow. Performance Improvement:

Self-migrating threads Zero-copy migration library


M++ Execution Model

Daemon Daemon Daemon

Daemon Network

LAN/SAN

Logical Network

Node Node

Node

Node

Link

1 2 3

1 3 1

hop(1@2)

Linkcreate Node with 3@2

1

Thread

Physical Network

Winter, 2004 CSS490 M++ 10

M++ Language Overviewclass Node { 　　　　　　　　　　 // Defining nodes (and links) as C++ cl

assespublic: int var;};

thread Thread { // Defining an M++ threadprivate: main() { // Executing its own behavior independently create node<Node> with 1; // Creating a network node, (link, and thread) hop( 1 ); // Migrating itself (and forking) node<Node>.var = 10; // Accessing the current node, (and link) }};

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M++ Compilation

Source program must have an mpp extension. may include two or more agent code.

The mpp compiler first preprocesses the source code into C++ files, each corresponding to a diffe

rent agent. pass them to the g++ compiler, and generates executable files, each again corr

esponding to a different agent.

m++@MEDUSA[16]% lsCar.mpp profilem++@MEDUSA[17]% m++ Car.mpp***** compiling GSCashier***** compiling SportsCar***** compiling Truckm++@MEDUSA[18]% lsCar.mpp GSCashier* SportsCar* Truck* profilem++@MEDUSA[19]%

Includes three pieces of agent code

Compile it with the m++ compiler

Message printed out from m++

Three executable files obtained

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M++ Profile

m++@MEDUSA[21]% cat profileport 10145hostnum 4mode sthread

describe daemonidmedusa 0mnode1 1mnode2 2mnode3 3describe_endm++@MEDUSA[22]%

Port A socket port # used for thread migration

Hostnum # PCs constituting the system

Mode Pthread or sthread (the latter is the M++ original thread library)

IP name and daemon ID

Each PC’s IP name and is corresponding daemon ID (>= 0).

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M++ Daemon Invocation Run “thrd” on each PC

Open a new window for each PC and type thrd, OR

Remotely login each PC and type “nohup thrd&”

All thrd print out “ready for being injected”

You are ready to launch new m++ threads.

m++@mnode3[4]% nohup thrd& exit[1] 6659logoutrlogin: connection closed.m++@mnode2[3]% nohup thrd& exit[1] 6678logoutrlogin: connection closed.m++@mnode1[3]% nohup thrd& exit[1] 8200logoutrlogin: connection closed.m++@MEDUSA[10]% thrd&[1] 4954port : 10145Connction established to medusa with daemon 0Connction established to mnode1 with daemon 1Connction established to mnode2 with daemon 2Connction established to mnode3 with daemon 3Total daemon(s) : 4Mode : sthreadStack : 65536 byteReady for being injected.m++@MEDUSA[11]%

Winter, 2004 CSS490 M++ 14

M++ Thread Launching

To launch a M++ thread, type Inject target_IPname executable_file #threads arguments

To stop the M++ system Bring back one of thrds to foreground and type cntl+c

m++@MEDUSA[11]% inject medusa ./GSCashier 1Injected 1 ./GSCashier thread(s) to medusam++@MEDUSA[12]% GSCashier: Waiting for cars.

m++@MEDUSA[12]% inject medusa ./Truck 1Injected 1 ./Truck thread(s) to medusam++@MEDUSA[13]% Truck: I'm at the GasStation.GSCashier: Injected fuel to TruckDiesel: 900 Regular: 1000GSCashier: Waiting for cars.Truck: I'm filled with fuel.

m++@MEDUSA[13]% fgthrdthrd: Interrupted.thrd: Closed all connections.thrd: Terminated.m++@MEDUSA[14]%

Winter, 2004 CSS490 M++ 15

M++ Language in DetailsThread Definitions and Deployment

A thread constructor receives arguments starting from argv[4]

A thread immediately starts its own execution in main( ).

thread Child { // spawned by a Parent threadpublic: Child(int argc, const char** argv):id( atoi(argv[5])){ strncpy(msg, argv[4], 16 ); } void main() { cout << msg << id << endl; }private: char msg[16]; int id;};

thread Parent { // injected firstpublic: void main( );private: int i; char idstr[10];};void Parent::main( ) { for (i=0; i<10; i<++ ) { // spawn 10 Child threads sprintf(idstr, “%d”, i); create thread<Child>(“I am Thread No”, idstr);} }

Winter, 2004 CSS490 M++ 16

M++ Language in DetailsNetwork Components

Components

Descriptions Definitions/usage

Daemon class

provides the current daemon status. It is system-predefined and read-only class.

daemon.name( ) returns the IP name.daemon.id( ) returns the daemon id.daemon.total( ) returns #daemons

DaemonObj class

is defined by a user and shared by all threads on the same daemon. Read/write

class DaemonObj { … };thread T { …} // all thread Ts share daemonObj

Nodes Includes an object of user-defined class. Each node can include an object of a different class.

class Place { … };Thread T { Void main( ) { create node<place>( ) with(nid@ did);}

Links Are visible from their endpoint nodes. They include an object of user-defined class. Each linke can include an object of a different class.

class Path { … };Thread T { void main( ) { create link<Path>( ) with slid to (nid@ did) with(dlid);}

Winter, 2004 CSS490 M++ 17

M++ Language in DetailsLogical Network Construction

Node creation and destruction [e]create node<NodeClassName>(argsList) with (NodeId[@DaemonId]); [e]destroy node(NodeId[@DaemonId]);

Link creation and destruction [e]create link<LinkClassName>(argsList) with (SrcLinkId) to (NodeId[@DaemonId] with (DestLi

nkId) [e]destory link(srcLinkId);

Only available in thread main( )

class Place { };class Path { };

thread Net {public: void main( ) { create node<Place>( ) with( 1@1 ); create link<Path>( ) with(10)to(1@1) with(20);} }

Daemon

Init

Daemon 0 1

0Place

110 20Path

Winter, 2004 CSS490 M++ 18

M++ Language in DetailsNetwork Navigation

[e]hop( [NodeId@DaemonId] ); [e]hopalong( srcLinkId ); [e]fork([ NodeId@DaemonId] ); [e]forkalong( srcLinkId );

class Place { };class Path { };

thread Net {public: void main( ) { create node<Place>( ) with( 1@1 ); create link<Path>( ) with(10)to(1@1) with(20); hop( 1@1 ); hopalong( 20 ); forkalong( 10 ); cout << “hi!” << endl; }}

Daemon

Init

Daemon 0 1

0Place

110 20Pathhi!

hi!

Winter, 2004 CSS490 M++ 19

M++ Language in DetailsInter-Thread Communication

Indirect communication: threads can read and write the same variable on the same node.

Thread 1hop( node3@daemon1 );node<Place>.var = 10;

Thread 2hop( node3@daemon1 );myVar = node<Place>.var;

Direct communication: A thread can access another thread directly.

Thread 1 reads Thread2myVar = Thread[2].myVar;

Thread 2 writes Thread1Thread[1].myVar = myVar;

Daemon

Place

var

write read

Thread 1 Thread 2

myVarmyVar

Indirect

Direct

Winter, 2004 CSS490 M++ 20

M++ Language in DetailsThread Synchronization

Nodes are monitors Unless a thread executes a network construction or a migration stat

ement, it can continuously and exclusively run on the current node. Synchronization statements

sleep: suspends until “wakeup threadId” or “wakeupall”. sleep node: suspends until “wakeup[all] node”. sleep daemon: suspends until “wakeup[all] daemon”. wakeup threadId: resumes the thread with threadId. wakeup node: resumes one thread sleeping on node. wakeup daemon: resumes one thread sleeping on daemon. wakeupall node: resumes all threads sleeping on node. wakeupall daemon: resumes all threads sleeping on daemon.

Winter, 2004 CSS490 M++ 21Transfer

SrcDaemon

UsrClass thrvar;thread Thread { main() { : hop(); :} };

200

UsrClass thrvar;

200

Execution

Thread

Pointer

Virtual function table

Pointer

Virtual function table

DstDaemon

200

Resume

Thread

New pointer

Old pointerCopy constructor

UsrClass thrvar;thread Thread { main() { : hop(); :} };

UsrClass thrvar;

200

ImplementationState Capturing

Winter, 2004 CSS490 M++ 22

AA CC

CC MainMain

11

AA BB CCMainMain

11 22

AA BB CCMainMain

AA BB CC MainMainAA BB CC

Pthread Library Sthread Library

User level

Kernel level

1:1:

2:

ImplementationThread Scheduling

Winter, 2004 CSS490 M++ 23

RAM

Thread 1

RAM

Network Interface Network Interface

Kernel Area Kernel Area

User AreaUser AreaSender Receiver

Thread 2Thread 3

Thread 1

Thread 2Thread 3

(1)

(3)(2) gather scatter

Packed Threads Packed ThreadThread 2Thread 3

Zero-copy transfer

Pin-downed pages

Immediateresumption

ImplementationZero-copy communication

Winter, 2004 CSS490 M++ 24

Exercises (No turn-in)1. Consider the pros and cons of MPI and M++

when used to design a multi-agent application.

2. Why and when is thread migration necessary?

3. What is zero-copy communication? Why is it so effective?

Winter, 2004 CSS490 M++ 25

Final Project Find a parallel application and program in both MPI a

nd M++. Compare their programmability and performance. You may have a partner. One codes an MPI version,

the other M++ version. Exclude the following applications (already programm

ed): Antfarm Artificial societies Growing neural network Matrix multiplication Mandelblot

Documents

CSS490 M++ Textbook No Corresponding Chapter