Taskflow-oriented Programming: A Method to Configure a ... · A Method to Configure a Universal...

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Taskflow-oriented Programming:A Method to Configure a Universal Clientfor Distributed Collaborative Computing

Franc Brglez, Hemang Lavana Collaborative Benchmarking Laboratory (CBL)

Dept. Comp. Science, NC State University

http://www.cbl.ncsu.edu/

Text


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Contents

Background and MotivationRelated WorkProject Drivers and GUITask Architecture and XML Schema RepresentationA Demo with Two Simple TasksA Demo with Concurrent Executions

..................................TaskFlow ArchitectureCollaborative Computing with TaskflowsConclusion and Summary

Franc Brglez. Taskflow-oriented Programming: A Method to Configure a Universal Client for Distributed Collaborative Computing. Invited talk, Cadence, 2001. https://people.engr.ncsu.edu/brglez/publications/OPUS2-2001-taskflow-Cadence-Brglez-talk.pdf


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Background and Motivation

Megaprogramming (Wiederhold 1992)Interactive programming (Wegner 1997)

What problem are we solving?What is a whitebox?Simple examples to illustrate needsWhat about protocols


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What Problem are We Solving?

Given: L blackbox components (executable programs) and test data,M whitebox components (explained below),N owners (up to L+M),K hosts (up to L+M).

Problem: create a new whitebox component and execute

Definitions:Task is a process of invoking and executing a componentTaskflow is a directed graph with tasks and data as vertices,task-to-task control-edges and data-to-task or task-to-data data edgesWhitebox component is a taskflow containing up to L+M components


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What is a Whitebox Component?

White box component is a taskflow containing up to L+M components:Programmable

- tasks can be sequenced serially or concurrently- the order of sequence can be decided by data- task may be repeated a number of times- only one entry and one exit point

Interactive, user-configurable during runtime - enabling/disabling of control edges to control the scope of execution- enabling/disabling taskflow for execution with local or global flow data

Collaborative - asynchronous mode- synchronous mode

Platform-independent - accessible from a web browser


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Simple Examples to Illustrate Needs

Task chaining (download address and print)

Task concurrency (check airfares with two on-line agents)

Task synchronization (select best fare and reserve itinerary)

Task cancellation (cancel 3rd query if reasonable price with first two)

Task reconfiguration (add one more on-line agent for search)

Synchronous collaboration (ask spouse to confirm itinerary)

Asynchronous collaboration (notify company to pay the fare)

Platform-independent (web-based access)


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What Protocols Can We Use

If components are X-compliant , where X = {rpc, CORBA, JavaRMI, SOAP},protocols such as rpc, CORBA, JavaRMI, SOAP may be used

... when creating a whitebox?

If components are not X-compliant ,protocols such as ftp, telnet, http, ssh may be used

In this research, we deal with components that are not X-compliant


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Related Work• Structured Workflow Modeling: http://www.icis.qut.edu.au/~arthur

•ToolWire http://www.toolwire.com

• Web-Based Electronic Design (WELD), WebTop, and CollabTop http://www-cad.EECS.Berkeley.EDU/Respep/Research/weld http://www-mit.mit.edu/CAPAM/demo-posters/deba

• Groupkit http://www.cpsc.ucalgary.ca/grouplab/groupkit

• Collaboratory for the Web: TANGO http://trurl.npac.syr.edu/tango

• VNC: Virtual Network Computing http://www.uk.research.att.com/vnc


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Highlights of on-going research

• a taskflow architecture to support concurrency

• a highly interactive GUI-based taskflow design and execution environment

• support for task ownership during asynchronous collaboration

• rendering collaboration-unaware tcl-applications collaborative

• web-accessibility of standalone tcl-applications


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Ranking Programming Languages for Concurrency Support

programming effort

concurrencysupport

low high

high

low

System languages (Ada, Java, ...)

A taskflow environment (cntML, based on XML)

Scripting languages (perl, python, tcl, ...)

The taskflow environment extends the capabilities of scripting languages twofold:(1) concurrency support without the complexity of thread programming(2) a highly interactive GUI taskflow design and execution environment


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Software vs Hardware Programming

T3bT1 T3a

T2a

T2bB1C1

i_t1 B2

C2

t1t2a

t2at3a

t2bt3a

t3at3b t3b_o

C3

A1

P1 P3P2P2

C1 B1 B2 C2

A1

C3

Module “X” in tcl

Module “X” in verilog

t1t2b


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Project Drivers and GUI

OpenDesign project (year 2000 of DARPA-funded Vela project)

OpenExperiment project (year 2000 of DARPA-funded Vela project)A prototype infrastructure for distributed and collaborative experimentaldesign, evaluating the performance of algorithms solving NP-hard problems,including the generation of equivalence class data sets.

OpenWriter project (senior class project)

http://www.ncsu.edu/OpenProjects/

Updates

A prototype infrastructure for distributed and collaborative VLSIsystems design, bringing together a number of university-basedand commercial electronic design automation tools.

A prototype infrastructure for distributed and collaborative writing,editing, and camera-ready technical report,article, and bookcomposition, using a number of open source software and utilities.


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pargen mentorWeb postproc extrstats

rootNameclasstreatmentinstanceNumdirNamestatsFile

rootNameclasstreatmentinstanceNumdirNamezipFile

URLinstanceNumverilogFileparFile

rootNameclasstreatmentinstanceNumdirNameverilogFileplcFile (opt)

tabFilestatsFileplcFile_TRxx

parFile zipFile

tabFile

rootNameclasstreatmentinstanceNumdirName

mentorflow

OpenDesign TaskFlow Example: NCSU--MSU (DAC’2000)


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A Tree View of a Hierarchical Taskflow

- (taskFlowInstance1 - InputList

• mIn1 = “fileIn1.t”• mIn2 = “fileIn2.t”

- OutputList• mOut1 = “fileOut1.r”

- TaskList• (Begin) |x|- (TaskA) |o|x|

+ InputList+ OutputList+ TaskList

- (TaskB) |x|+ InputList+ OutputList

+ (TaskC) |o|x|• (End)

} single task

} multi task

invoke task

open graphView

XO


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A Graph View of a Hierarchical Taskflow

(TaskA)

(TaskC) (End)(Begin)

(TaskB)

hierarchical task

primitive task

user-controllededge

Execute task by clicking the “task button” Abort task by clicking the “flashing task button”

FSMD states:• white (task not yet executed)• yellow (task “aborted” )• green (task “executing” )• blue (task forkCondition is “valid”)• violet (task forkCondition is “invalid”)• pink (task “timed-out” )• red (task “aborted” )

mIn1 = “fileIn1.t”


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Task Architecture and XML Schema RepresentationEncapsulatedSingleTask

(FSMD)EncapsulatedMultiTask

(FSMD)

SingleTaskBodyBeginForkBlackBox Comp.EndJoin

SingleTaskDefn (STD)InputPortListInOutPortListOutInPortListOutputPortList

MainTaskTaskInstanceListTaskGraphBeginForkTaskInstance1...EndJoin

TaskInstanceControlJoinDataMuxEncapsulatedTaskControlFork

MultiTaskBodyBeginForkTaskInstance1...EndJoinDataGraph

MultiTaskDefn (MTD)InputPortListInOutPortListOutInPortListOutputPortListTaskInstanceListTaskGraph


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Y_taskPrimitives-b

Tosuccessor

tasksFrompredecessor

tasksBBCdata

BBCdata

Black-Boxcomponent

FSMDtask

config.data

BBCdata

BBC

BBCdata

Reset

BF,CFBegin Fork,Control Fork

DM

DataMux

EJ,CJ

End Join,Control Join

BBC data

flowData/localData


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Y_taskArchitecture

To Nsuccessor

tasks

From Mpredecessor

tasks

flowData/localData

taskconfig.

data

FSMDInvokeAbortSkip

WaitingEnabledXecuting

C ompletedDone

AbortedT imedOut

Skipped

BBCor

WBC

completion status

invocationsignal

CFCJ

DM

Reset

M

M

MM

M

N

N

Efi

CIi

Fi

Li

COi

DOutDIn

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XML Schema Specification for MTD<xsd:complexType name ="MultiTaskDefn " content="elementOnly"> <xsd:sequence minOccurs=" 0" maxOccurs=" 1"> <xsd:element name ="Title" type ="Title"/> <xsd:element name ="Description " type ="Description"/> <xsd:element name ="InputList" type ="InputList"/> <xsd:element name ="InoutList " type ="InoutList"/> <xsd:element name ="OutputList " type ="OutputList"/> <xsd:element name ="TaskList " type ="TaskList"/> <xsd:element name ="ControlGraph "> <xsd:complexType content="textOnly"> </xsd:complexType> </xsd:element> </xsd:sequence> <xsd:attribute name ="name "> <xsd:simpleType base="xsd:string"/> </xsd:attribute></xsd:complexType>


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XML Editor for Taskflow Construction

An XMLspy editor validates taskflow during construction itself


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Y_taskFlowSchedulingEngine

XMLTaskflows

Tcl-xmlParser

ValidateTaskflow Specs

Display TaskflowTree, Graph

TaskflowScheduler

EvaluateControlJoin

Enable Task

Execute BBCor expand WBC

EvaluateControlFork

Foreachchild task

Begin

False

False

No moretasks

Noop

Noop

End

TaskflowScheduler


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A Demo with Two Simple Tasks (single pSolver)

Demos

• hierarchical task tree/graph views

• taskflow simulation execution

• taskflow local data execution

• edit data represented by data I/O nodes

• taskflow flow data execution

Descriptions

BlackBox


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parabola_main.ctd<Cdtml>

<MainTask> <TaskList> <Begin/> <Task instance="(parabola)" \ taskRef="parabola_defn.cdt#task_parabola"/> <End/> </TaskList> <TaskGraph> (BEGIN) => (parabola) => (END) </TaskGraph>

<TaskInstance instance="(parabola)"> <SetInput port="mInDescrA1"> <LocalValue> pbInDescrA1.d </LocalValue> </SetInput> <SetInput port="mInitCost"> <LocalValue> 1e6 </LocalValue> </SetInput> <SetOutput port="mOutReport"> <LocalValue> parabola.rpt </LocalValue> </SetOutput> </TaskInstance></MainTask>

</Cdtml>


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parabola_defn.ctd

<TaskList> <Begin/> <Task instance="(InitA1)" taskRef="parabola_defn.cdt#pInitSolver"/> <Task instance="(A1)" taskRef="parabola_defn.cdt#pSolver"/> <End/> </TaskList> <TaskGraph> (BEGIN) => (InitA1) => (A1) => (END) (A1) => (A1) </TaskGraph>

<MultiTaskDefn name="task_parabola" \ bodyRef="parabola_body.cdt#task_parabola"> <InputList> <Input port="mInDescrA1" type="persistent"> <Title> Input description for task A </Title> </Input> <Input port="mInitCost" type="temporary"> <Title> Initial cost (should be very large) </Title> </Input> </InputList> <OutputList> <Output port="mOutReport" type="persistent"> <Title> Output report of parabola cost function evaluation </Title> </Output> </OutputList>

Note the backedge(self-loop)


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parabola_body.ctd (1)

<MultiTaskBody name="task_parabola" sleep=""> <BeginFork/>

<TaskInstance instance="(A1)" maxIterate="10" host="h1"> <DataMux> <SetInput port="inpDescr"> <LocalValue> taskA1_inpDescr.d </LocalValue> </SetInput> <SetInput port="initCost"> <LocalValue> 1.e6 </LocalValue> </SetInput> <SetInput port="initSoln"> <LocalValue> 5 </LocalValue> </SetInput> <SetOutIn port="newCost"> <LocalValue> taskA1_newCost.d </LocalValue> </SetOutIn> <SetOutIn port="newSoln"> <LocalValue> taskA1_newSoln.d </LocalValue> </SetOutIn> <SetOutput port="nIter"> <LocalValue> taskA1_nIter.d </LocalValue> </SetOutput>

(A1)pSolver


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parabola_body.ctd (2)

<SetOutput port="oldCost"> <LocalValue> taskA_oldCost.d </LocalValue> </SetOutput> </DataMux> <RepeatCondition> <UserRepeat> evalRepeatCondition \ "[cdtReadData newCost]" IsLessThan "[cdtReadData oldCost]" </UserRepeat> </RepeatCondition> </TaskInstance>

<SingleTaskBody name="pSolver" sleep=""> <ExecCommand type="TclCmd"> <Value> pSolver.tcl "[cdtGetData inpDescr]" "[cdtGetData initCost]" \ "[cdtGetData initSoln]" "[cdtGetData newSoln]" \ "[cdtGetData newCost]" "[cdtGetData nIter]" \ "[cdtGetData oldCost]" </Value> </ExecCommand></SingleTaskBody>


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Single Parabola Demo Outline

-- introduce hierarchical task tree and graph views turn off/on control edges

-- introduce taskflow simulation modeenter 1 second wait/task (random variable otherwise. 0--5 seconds)execute taskflow with all edges turned on

-- introduce taskflow local data executionprobe data nodes for data values expected by task (initA1)probe data I/O nodes for data values assigned to task (A1)

(not all data is present yet)turn off all edges except (initA1) -> (A1)click on (initA1), continue clicking on (A1) until “minimum” is declaredprobe data I/O nodes for data values assigned to task (A1)

-- edit data represented by data I/O nodesclick on pbInDescrA1.d an edit contents (but don’t) save

-- introduce taskflow flow data execution (here, we get the same results)make sure all edges are connected, reset and clean all dataclick on (Begin)probe data I/O nodes for data values assigned to task (A1)


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A Demo with Concurrent Task Executions

(A2)pSolver

(A3)pSolver

(END)(B)pEval(BEGIN) (C)

pReport

(A1)pSolver

see the 2-out-3 synchronizationpattern in ..._body.cdt (next page)

A1, A2, A3 should executeconcurrently

if on different hosts


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......._main.ctd<MainTask> <TaskList> <Begin/> <Task instance="(parabola)" taskRef="parabola_defn.cdt#task_parabola"/> <End/> </TaskList> <TaskGraph> (BEGIN) => (parabola) => (END) </TaskGraph>

<TaskInstance instance="(parabola)"> <SetInput port="mInDescrA1"> <LocalValue> pbInDescrA1.d </LocalValue> </SetInput> <SetInput port="mInDescrA2"> <LocalValue> pbInDescrA2.d </LocalValue> </SetInput> <SetInput port="mInDescrA3"> <LocalValue> pbInDescrA3.d </LocalValue> </SetInput> <SetInput port="mInitCost"> <LocalValue> 1e6 </LocalValue> </SetInput> <SetOutput port="mOutReport"> <LocalValue> parabola.rpt </LocalValue> </SetOutput> </TaskInstance></MainTask>


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......._defn.ctd

<TaskList> <Begin/> <Task instance="(InitA1)" taskRef="parabola_defn.cdt#pInitSolver"/> <Task instance="(InitA2)" taskRef="parabola_defn.cdt#pInitSolver"/> <Task instance="(InitA3)" taskRef="parabola_defn.cdt#pInitSolver"/> <Task instance="(A1)" taskRef="parabola_defn.cdt#pSolver"/> <Task instance="(A2)" taskRef="parabola_defn.cdt#pSolver"/> <Task instance="(A3)" taskRef="parabola_defn.cdt#pSolver"/> <Task instance="(B)" taskRef="parabola_defn.cdt#pEvaluator"/> <Task instance="(C)" taskRef="parabola_defn.cdt#pReport"/> <End/> </TaskList> <TaskGraph> (BEGIN) => (InitA1) => (A1) => (B) => (C) => (END) (A1) => (A1) (BEGIN) => (InitA2) => (A2) => (B) => (C) => (END) (A2) => (A2) (BEGIN) => (InitA3) => (A3) => (B) => (C) => (END) (A3) => (A3) </TaskGraph></MultiTaskDefn>


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......._body.ctd <TaskInstance instance="(B)"> <JoinCondition> <UserInvoke> evalJoinCondition MINIMUM 2 \ {(A1) Valid} {(A2) Valid} {(A3) Valid} </UserInvoke>

••••••••••••••••••••••••••••••••

<SetOutput port="costAvg"> <LocalValue> taskB_costAvg.d </LocalValue> </SetOutput> <SetOutput port="count"> <LocalValue> taskB_count.d </LocalValue> </SetOutput> </DataMux> </TaskInstance>

<DataGraph> mInDescrA1 -> (A1).inpDescr mInDescrA2 -> (A2).inpDescr mInDescrA3 -> (A3).inpDescr mInitCost -> (A1).initCost mInitCost -> (A2).initCost mInitCost -> (A3).initCost (A1).newCost -> (B).costA1 (A2).newCost -> (B).costA2 (A3).newCost -> (B).costA3 (B).totalCost -> (C).totalCost (B).costAvg -> (C).costAvg (B).count -> (C).count (C).outReport -> mOutReport </DataGraph></MultiTaskBody>

2-out-of-3synchronization

pattern


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Concurrent Executions Demo Outline-- taskflow simulation mode

click “exec checkboxes” so that tasks B anb C are always executed ...do task (A1) by repetitive clicks (with repeat-edge off)do task (A3) single node with repeat-edge onwhen (A3) is completed task (B) should fire (regardless of (A2) state)enter 2 seconds of sleep/task, do the entire taskflow, blocking one edge (watch the concurrent 3-task execution)modify source file to have tasks A1, A2, A3 executed on single host (forcing a serial execution of the three tasks)

-- taskflow local data executionturn-off all edges to (B)check for input data and lack of output datado tasks (A1), (A2), and (A3) concurrently check that now we have input data for (B) but not yet (C)click on (B) which invokes (C)

-- taskflow flow data executionconnect the entire flowcheck for input data and lack of output datado tasks (A1), (A2), and (A3) concurrently check that now we have input data for (B) but not yet (C)click on (B) which invokes (C)connect the entire flow and re-execute to get final results in a single click ....


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TaskFlow Architecture

• Task Primitives• Task Primitives Encapsulation• Task Primitives Instances• TaskFlow Graph Model • Two State One Task Example (in hardware)• Four State One Task Example (in hardware)• Task Architecture• Task FSMD• TaskFlow Views TaskFlow Scheduling Engine


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Y_taskPrimitives-a

control port for task invocation (input)

control port for task execution status (output)

control port for task abort (input/output)

port for temporary/persistent data (input/output/inout)

port for temporary/persistent data pair (input/output/inout)

port for temporary/persistent data stack (input/output/inout)

port for temporary/persistent data pair stack (input/output/inout)temporary/persistent datatemporary/persistent data stack

control abort connector (port-port, opened/closed by user)control invocation connector (port-port, opened/closed by user)control invocation connector (port-port, always closed)data connector (data-port, port-data or port-port)


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Y_taskPrimitives-b

Tosuccessor

tasksFrompredecessor

tasksBBCdata

BBCdata

Black-Boxcomponent

FSMDtask

config.data

BBCdata

BBC

BBCdata

Reset

BF,CFBegin Fork,Control Fork

DM

DataMux

EJ,CJ

End Join,Control Join

BBC data

flowData/localData


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Y_taskPrimitivesEncap-a

BBC

BBCdata

ResetFSMDtask

config.data

WBCdata

WBC

WBCdata

ResetEncapsulated WBC

Invoke/Abort

ResetFSMDtask

config.data

BBCdata

BBC

BBCdata

ResetEncapsulated BBC

Invoke/Abort


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Y_taskPrimitivesEncap-b

WBC (White-Box Component)

TaskInstance1

TaskInstance2 TaskInstance3

EJBF


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Y_taskPrimitivesInstance-c

Frompredecessor

tasks

user

CF

ResetFSMDtask

config.data

BBCor

WBCdata

BBCor

WBC

Reset

Dout

DMflowData/localData

CJ

Din (local)

Din (flow)

Task Instance

Tosuccessor

tasks

userEncap. BBC/WBC


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Y_taskFlowGraphModel-a

For each user invocation,

for each user abort edge,

there is a corresponding

program invocation and

program abort edge.

Frompredecessor

tasks

F/L

user

user

Din (local)

Din (flow)

Taskinstance

k

Tosuccessor

tasks

user

Dout

R ... user reset of task X ... user invocation of taskA ... user abort of task S ... user skip of task F/L ... user task data select

AXR S


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Y_taskFlowGraphModel-b

T1

T2 T3Din Dout

BF EJ


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S QR Q

SyncBBC

act com

done

reset

enable

clock

y

Y_2stateOneTaskExample (in hardware)

S QR Q

BBC

act com

reset

enable doney


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Y_4stateOneTaskExample (in hardware)

QX

QC

QD

Pi

R

S QR Q

S QR Q

y1

y2

pulse gen.

counteri > Imax OR

cost(i) > cost(i-1)

YESNO

tdtr tc

X/W

C/X

X/C

D/C

BBC


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Y_taskArchitecture

To Nsuccessor

tasks

From Mpredecessor

tasks

flowData/localData

taskconfig.

data

FSMDInvokeAbortSkip

WaitingEnabledXecuting

C ompletedDone

AbortedT imedOut

Skipped

BBCor

WBC

completion status

invocationsignal

CFCJ

DM

Reset

M

M

MM

M

N

N

Efi

CIi

Fi

Li

COi

DOutDIn


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Y_taskFSMD

Finite State Machine(as per FSM transition table)

Datapath(as per datapath table)

R

BBCor

WBC

completion status

invocationsignal

DoutDin

taskconfig.data

{ Pi , Pa , Ps }

{ QE , QX ,

....,QS }

• • • • • •


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Y_taskFlowViews1-a

- (taskFlowInstance1 - InputList

• mIn1 = “fileIn1.t”• mIn2 = “fileIn2.t”

- OutputList• mOut1 = “fileOut1.r”

- TaskList• (Begin) |x|- (TaskA) |o|x|

+ InputList+ OutputList+ TaskList

- (TaskB) |x|+ InputList+ OutputList

+ (TaskC) |o|x|• (End)

} single task

} multi task

invoke task

open graphView

XO


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Y_taskFlowViews1-b

(TaskA)

(TaskC) (End)(Begin)

(TaskB)

hierarchical task

primitive task

user-controllededge

Execute task by clicking the “task button” Abort task by clicking the “flashing task button”

token holder states:• white (task not yet executed)• yellow (task “aborted” )• green (task “executing” )• blue (task forkCondition is “valid”)• violet (task forkCondition is “invalid”)• pink (task “timed-out” )• red (task “aborted” )

mIn1 = “fileIn1.t”


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Y_taskFlowSchedulingEngine

XMLTaskflows

Tcl-xmlParser

ValidateTaskflow Specs

Display TaskflowTree, Graph

TaskflowScheduler

EvaluateControlJoin

Enable Task

Execute BBCor expand WBC

EvaluateControlFork

Foreachchild task

Begin

False

False

No moretasks

Noop

Noop

End

TaskflowScheduler


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Collaborative Computing with Taskflows

- Asynchronous Collaboration

- Synchronous Collaboration

- Asynchronous and Synchronous Collaboration

- Web-Interface to Taskflow Environment


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Asynchronous Collaboration: Task and Data Ownership

Ownership assignment to tasks- Input and output data inherit ownership of task

Shared data at ownership boundries (conflict)- Use read/write locks to resolve conflicts- Add `buffer’ task with dual ownership

Two users U1 and U2- U1(A), U1(B)- U2(C), U2(D)

A D

SharedData

U1 U1

B

U2 U2

C


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Asynchronous Collaboration: Ownership Locking

A D

SharedDataU1

BU2

C

A D

SharedData

U1

B

U2

C

readlock(C-read)writelock(B-write)

readlock(B-write)writelock(C-read)

AsynchronousGroup Server

(AGS)


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Asynchronous Collaboration: Buffer Task

A

U1

B

MutualConsent

AsynchronousGroup Server

(AGS)

DU2

CB-C

U1+U2

A

U1

B D

U2

CB-C

U1+U2


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Synchronous Collaboration: GroupKit Vs VNC

U1 U2

CentralizedVNC Server

DistributedGroupKit Client

DistributedGroupKit Client

CompressedPixel Image

Selective DataSynchronization


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Synchronous Collaboration Architecture

U1 U2

Selective DisplaySynchronization

SynchronousGroup Server

(SGS)

SynchronousGroup Client (SGC)

SynchronousGroup Client (SGC)


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Asynchronous and Synchronous Collaboration: OmniDesk

A

U1

B

MutualConsent

DU2

CB-C

U1+U2

A

U1

B D

U2

CB-C

U1+U2

OmniDesk(AGS+SGS)

OmniFlow+ SGC

OmniFlow+ SGC


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Web-Interface for the Environment

Web-browsers are here to stay (for a while anyway ...)

Questions:

• Can we use a web-browser for our environment?

Features expected (at least):

• hierarchy of windows

• no tedious installation

• access to file system, printing

• security of applets


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Tcl-Plugin: Restrictions and Solutions

Restrictions of Tcl-plugin code:

• no auto_load mechanism

• partial set of Tk widgets

• no standard input/output

Current coding techniques for Tcl-plugins:

• merge all tcl application scripts into a single file

• require each client to install the application package

• (re-)design the application GUI to contain a single window

• use an appropriate security policy


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WebWiseTclTk Architecture

TcletScripts

WebWiseTclTkToolkit

Web ServerHosting Tclets Tclet

home policyClient Host

Web Browser

Tcl-Plugin

Downloads the toolkit as well as the tclet scripts from the web server


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Implementation of a ‘toplevel’ Window Using Frames

Menubar

Frame correspondingto toplevel window

Resize window in bothdirections simultaneously

Kill Window Title Iconify Maximize

Resize window in vertical direction

Resize window in vertical direction

Resize window inhorizontal direction


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Example: TkWidget Demos


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Evaluation of WebWiseTclTk using TkWidget Demos

Category Scripts Action events Pass Fail DiagButtons, . . . 8 23 (1+4+3+5+2+4+1+3) 22 1Listboxes 3 10 (3+4+3) 9 1Entries 3 15 (6+7+2) 15Text 5 16 (3+3+2+6+2) 15 1Canvases 7 20 (4+2+5+3+2+2+2) 17 3Scales 2 2 (1+1) 2Menus 2 11 (5+6) 9 2Dialogs 3 4 (1+2+1) 0 4Miscellaneous 3 3 (1+1+1) 2 1 0Total 36 104 91 5 8


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Conclusion and SummaryKey contributions of this work:

• a taskflow architecture to support concurrency• a highly interactive GUI-based taskflow design and execution environment• support for task ownership during asynchronous collaboration• rendering collaboration-unaware tcl-applications collaborative• web-accessibility of standalone tcl-applications

Benefits: • scalability: large user-configurable programs can be composed from

existing legacy programs for network-transparent cross-platform execution.• flexibility to control standalone execution of subtasks.• flexibility to decompose any computing project into a hierachy of tasks,

-- bind the tasks and data to taskflow instances, -- delegate the subtasks to distributed team members,-- support asynchronous and synchronized execution policies.

Future work: • extended formalization of the control/data taskflow model.• optimize resource utilization and perform load balancing.

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