A TRICKY TASK SCHEDULING TECHNIQUE TO OPTIMIZE TIME COST AND RELIABILITY IN MOBILE COMPUTING ENVIRONMENT

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1 A TRICKY TASK SCHEDULING TECHNIQUE TO OPTIMIZE TIME COST AND RELIABILITY IN MOBILE COMPUTING ENVIRONMENT Faizul Navi Kha 1, Kapil Govil 2 1 Departmet of Computer Applicatio, Teerthaker Mahaveer Uiversity, Moradabad , UP, INDIA 2 Departmet of Computer Applicatio, Teerthaker Mahaveer Uiversity, Moradabad , UP, INDIA Abstract Mobile Computig Eviromet (MCE) cosistig portable computig devices itercoected by wireless medium, are icreasigly beig used i may area of sciece, busiess ad educatio etc owadays. It is the computatio made over physical mobility. MCE facilitate the user to perform a task from a distat place from the device. This provides flexible commuicatio betwee user ad cotiuous access to etworked services. Mobile computig shares may features with distributed computig as the applicatio rus i MCE executes i distributed maer i.e. a applicatio is combiatio of multiple tasks ad these task schedule o the available resources to be execute. The performace of a applicatio is depedig o task schedulig techique i MCE. Task schedulig techique cosist i fidig a allocatio of the tasks to the processors such that the total executio cost ad time are miimized or processig reliability is maximized. So the ultimate objective of fidig task schedulig techique is to improve the performace i terms to miimize cost ad time ad maximize reliability of MCE. I MCE a applicatio ca be see as oe or multiple task modules ad each of the task modules allocate o available processor for its executio. Therefore, i this paper, the problem of schedulig the tasks i mobile computig eviromet is explore with objectives to miimize processig cost, processig time or maximize the processig reliability through a ew task schedulig techique to optimize performace i MCE. The ature of the assigmet will be static. Keywords Cost, Mobile Computig Eviromet, Performace, Reliability, Task schedulig *** INTRODUCTION Advaces i commuicatio ad computig techologies have itroduced a ew way of computig eviromet, called Mobile Computig Eviromet (MCE), which allows mobility of users thereby providig aytime aywhere computig eviromet. The mobility of user (or device) results i a highly dyamic eviromets with respect to the availability of resources/ifrastructures for ay applicatio ruig o the mobile devices. Also, i a mobile computig eviromet, locatio has a profoud effect. A Mobile Computig Eviromet (MCE) cosists of a set of multiple processors itercoected by wireless commuicatio liks ad equipped with software systems to produce a itegrated ad cosistet processig eviromet. The task partitioig ad schedulig strategies also play a importat role for achievig high performace i MCE ad a efficiet task schedulig techique ca utilize the resources i the MCE to complete the task executio at the earliest or i optimize maer. Task schedulig is a very commo ad challegig problem i MCE ad it deals with fidig a optimal schedulig of tasks to the processors so that the processig cost ad processig time are be miimized ad the processig reliability is maximized without violatig ay of the system costraits. Processig time is referred as the time take by the task for its executio, expeses occurs durig the task executio is describe as the processig cost ad reliability ca be cosider as the reliability of its processors as well as the reliability of its commuicatio liks. Distribute data across processors uevely so that each processor performs the volume of computatio proportioal to its speed is a commo approach to solve task schedulig problem i MCE. This problem deals with fidig a optimal task schedulig techique to the processors so that the processig time ad cost ca be miimized ad processig reliability ca be maximized for task schedulig i MCE. I MCE, the objective is to make processors busy executig tasks all the time by esurig that it does ot get idle ad this serves the purpose. Task optimizatio is highly depedet o the tasks allocatio method oto the available processor. I order to improve the performace of MCE, applicatio workloads are divided ito small idepedets uits called tasks ad these tasks eed to be execute o available processor through a task schedulig techique. Task schedulig techique should be capable eough i terms of optimize processig capabilities i MCE i.e. miimize processig cost, miimize processig time ad maximize processig reliability. This research paper explore task schedulig problem with umber of processors ad m umber of tasks where m> i MCE ad these tasks are eed to schedule o the available processors i optimize maer with satisfyig the processig costraits i.e. time, cost ad reliability. I task schedulig problem oce available processors are scheduled with a sigle task while the remaiig tasks have to wait (if the umbers of task are greater tha umbers of processor) util the preset scheduled task will execute. To overcome such problem i a MCE, a task schedulig techique would be eeded where more tha oe task to a sigle processor ca be schedule i Volume: 03 Issue: 05 May-2014, 823

2 order to achieve miimum processig time, processig cost ad maximum processig reliability i MCE. Some of the task allocatio schemes have bee reported i the literature, such as Task modelig [1], Schedulig of tasks [2, 5, 7, 8, 11], Task allocatio scheme [3, 15, 20], Resource allocatio [4, 13, 14, 16, 19], Load balacig [10], Static task assigmet [6], Resource schedulig [9], Job schedulig algorithm [12], Resource maagemet ad schedulig [17], Applicatio schedulig i Mobile Cloud Computig [18]. This research paper propose a ew task schedulig techique to task allocatio i MCE by usig the proper utilizatio of processors of the MCE so the problem of load balacig ca be avoid. 2. NOTATIONS p t m TCR MTCR 3. OBJECTIVE Processor Task Number of Processors Number of Tasks Task Cost Reliability Modified Task Cost Reliability The objective of this research paper is to solve task schedulig problem i a efficiet maer so that maximum level of optimizatio is achieved i order to miimize processig cost ad time ad maximize reliability by the proper utilizatio of resource i Mobile Computig Eviromet (MCE). The applied techique would also esure that processig of all the tasks ad its sub tasks as task modules are more tha the umbers of processors i the MCE. The type of assigmet of tasks to the processor is static. I this research paper performace is measured i term of processig time, cost ad reliability of the task that have to be get processed o the processors of the eviromet ad it have to be optimally processed i.e., time, cost to be miimized ad reliability maximized. 4. TECHNIQUE I order to obtai the overall optimal processig cost or processig time or processig reliability of a Mobile Computig Eviromet (MCE), this research paper cosider a problem of task schedulig where a set P = {p 1, p 2, p 3, p } of processors with differet processig capabilities ad a set T = {t 1, t 2, t 3, t m } of m tasks, where m>, every task has also cotai some umber of sub tasks module. Processig time, cost ad reliability are kow for each tasks module to the processor ad arrage i TCTR. Iitially processig cost, processig time will be iitializig as zero (0) ad processig reliability as oe (1). Task schedulig algorithm will fid for the miimum value by row (without repeatig the colum i the matrix) for processig time, cost or maximum for processig reliability, i result would get the tasks equal to umber of processors available i the MCE ad those task will get assiged. The process will repeat util umber of tasks will remai lesser tha the processor available i the eviromet. Oce that situatio will occur where the umbers of processors are greater tha the tasks waitig for the processig the will make slide chage i the techique. Istead of searchig elemet row wise, the search will be colum wise that will make eable the fial allocatio of remaiig uscheduled task i MCE. The fuctio to calculate overall time [Etime], cost [Ecost] ad reliability [Ereilability] is give here: Etime = Ecost = Ereliablity = 5. ALGORITHM i=1 i=1 i=1 i=1 i=1 ET ij X ij EC ij X ij i=0 ER ij X ij (i) (ii) (iii) 1. Start Algorithm 2. Read the umber of task i m 3. Read the umber of processor i 4. Store task ad Processig Cost, time ad reliability ito Matrix PCTR (,) x m of order 5. While (All task! = Assiged) { i. Check if the matrix cotaiig umbers of tasks are greater tha or equal to umbers of processors (m>=) the go to step (ii) else step (iv) ii. Search miimum value row wise i the matrix for time, cost or maximum value for reliability. iii. Check if the colum is previously selected for miimum/maximum value the GO TO step (ii) to fid ext miimum value for the row else Goto step (vi) to assig eligible task. iv. Search the miimum value for cost, time or maximum value for reliability colum wise i the matrix v. Check if the row is previously selected for miimum or maximum value the GO TO step (iv) to fid ext miimum or maximum value for the colum else Goto step (vi) to assig eligible task. vi. } 6. State the results 7. Ed of algorithm Assig the eligible tasks to available processors 6. IMPLEMENTATION This research paper cosider Mobile Computig Eviromet (MCE) which cosist a set P of 3 processors {p 1, p 2, p 3 }, ad a set T of 3 tasks {t 1, t 2, t 3 }. Each tasks cotaied some umber of modules ad these modules belogs to differet tasks would be process o available processors i MCE as metioed i metioed i Figure 1. Volume: 03 Issue: 05 May-2014, 824

3 Table 1: Tasks ad their modules t 1 {m 11, m 12, m 13, m 14,m 15, m 16} t 2 {m 21, m 22, m 23, m 24, m 25, m 26, m 27} t 3 {m 31, m 32, m 33, m 34, m 35, m 36, m 37, m 38 } Fig 1: Task modules origiatig from differet mobile hosts are waitig i queue. Each task cotaied differet idividual task compoets which are kow as modules. The processig time (t), processig cost (c) ad processig reliability (r) of each task modules to each processor are kow ad metioed i Processig Cost Time Reliability (PCTR) matrix as metioed i Table 2 Table 2: Processig Time Cost Reliability Matrix Processors p 1 p 2 p 3 Task Modules t-c-r t-c-r t-c-r t 1 m m m m m m t 2 m m m m m m m t 3 m m m m m m m m To proceed further with task schedulig problem i PCTR matrix, cosiderig that t 1 is based o processig time (t) (it may be processig cost or reliability), task t 2 is based o processig cost (c) (it may be processig time ad reliability) ad task t 3 is based o processig reliability (r) (it may be processig time ad processig cost). Hece a ew matrix amed MPCTR ca be derived by usig PCTR, I MPCTR task t 1 will represet processig time (t), t 2 task processig cost (c) ad t 3 task processig reliability (r). New matrix MPCTR represet as Table 3: Table 3: Modified Processor Cost Time Reliability Matrix Processors p 1 p 2 p 3 Task Modules t-c-r t-c-r t-c-r t 1 m m m m m Volume: 03 Issue: 05 May-2014, 825

4 m t 2 m m m m m m m t 3 m m m m m m m m MPCTR ca be break ito three differet tables for each costrait i.e. Table 4 for processig time, Table 5 for processig cost ad Table 6 for processig reliability i order to demostrate all the three costraits of processig i.e. time cost ad reliability i Mobile Computig Eviromet (MCE). Table 5: Processig Cost m 21 m 22 m 23 m 24 m 25 m 26 m 27 p p p Table 4: Processig Time m 11 m 12 m 13 m 14 m 15 p p p Table 6: Processig Reliability m 31 m 32 m 33 m 34 m 35 m 36 m 37 m 38 p p p To demostrate ew schedulig techique, this research paper is iitially cosiderig Table 4 for task schedulig i MCE. Table 4 represet umber of five modules which are origially belogs to task t 1 eed to get schedule o umber of 3 processors. I Table 4 umbers of task modules are 5 ad the umbers of processors are 3 (m>), schedulig techique will determie miimum value for each row ad will get the resultig output as metioed i Table 7: Table 7: Matrix represetig miimum value m 11 m 12 m 13 m 14 m 15 p 1 15 p 2 16 p 3 18 Hece there are oly three processors i the eviromet, employed techique would schedule oly three task module i MCE as metioed i Table 8. Table 8: Schedulig Table Processor Task Processig Cost p 1 m p 2 m p 3 m After the first task schedulig step executio, still two task i the queue ad gets uscheduled, here umbers of processors are greater tha umber of task (two) (m<), ow the elemet will be searched by colum wise ad that approach will esure that oe of the task module will get remai Volume: 03 Issue: 05 May-2014, 826

5 uexecuted. Ad the fial task schedulig is metioed i Table 9. Table 9: Overall processig time Processor Task Processig Etime time p 1 m 11 * m p 2 m p 3 m 13 * m Graphical represetatio of overall processig time is metioed i Fig 2: Fig 3: Overall processig cost occurred durig the executio i MCE Table 11: Overall processig reliability Processor Task Processig Ereliability Cost p 1 m 31* m 34 * m 36 p 2 m 33 * m 37 * m p 3 m 32* m Fig 2: Overall processig time take by the processor i MCE Figure 4 showig graphical represetatio of overall processig reliability of give example: By applyig the same task schedulig techique, this research paper would also calculate processig cost ad processig reliability for the give example i this research paper as metioed i Table 10 ad Table 11 respectively. Table 10: Overall processig cost Processor Task Processig Ecost Cost p 1 m 22 * m 25 * m 27 p 2 m 23 * m p 3 m 21* m Graphical represetatio of overall processig cost is metioed i Fig 3: Fig 4: Overall processig reliability of the task i MCE 7. CONCLUSIONS This research paper provide the solutio to the problem of task schedulig through a smart task schedulig techique, i which the umber of the tasks is more tha the umber of processors i Mobile Computig Eviromet (MCE). Opted schedulig techique will esure to satisfy various costraits i.e. time, cost ad reliability i MCE. The task schedulig techique is preseted i pseudo code ad applied o the several sets of iput data to test the performace ad effectiveess of the pseudo code. Optimizatio of task is the commo objective for ay task schedulig problem that the Volume: 03 Issue: 05 May-2014, 827

6 task eeds to be processed with optimal time, cost ad reliability. This paper cosider three tasks i.e. t 1, t 2 ad t 3 with differet tasks module ad process t 1 with miimum time, t 2 process with miimum cost ad t 3 process with maximum reliability i MCE. The optimal output of the give example that is cosider i research paper to test the task schedulig techique is metioed i the implemetatio sectio of the paper is metioed i Table 12: Table 12: Cosolidated results for Time, Cost ad Reliability i MCE Task p 1 p 2 p 3 Optimal ETime Optimal ECost Optimal Ereliablity t1 m 11 * m 14 m 12 m 13 * m t2 m 22 * m 25 * m 27 m 23 * m 24 m 21 * m t3 m 34 * m 31 * m 36 m 33 * m 37 * m 38 m 32 * m Time complexity comparisos (as metioed i Table 13) are show i Figure 6, 7 ad 8. Fig 5: Fial Task Schedulig i Mobile Computig Eviromet (MCE) The techique stated i pseudo code applied o several sets of iput data ad that verified the objective of get maximum processig reliability for give tasks for their executio. The aalysis of a algorithm maily focuses o time complexity. The time complexity of above metioed algorithm is O(m+). By takig several iput examples, the above algorithm returs results as metioed i Table 13. Fig 6: Time complexity for No of Processors 3 Number of Processors () Table 13 Time Complexity Number Complexity of of tasks algorithm [5] (m) O(m 2 ) Complexity of preset algorithm O(m+) Fig 7: Time complexity for No of Processors 4 Volume: 03 Issue: 05 May-2014, 828

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