Decentralized Scheduling Algorithm for DAG Based Tasks on P2P Grid

Algorithm 1

Fully decentralized P2P grid scheduling (FDPGS) algorithm for DAG based task.

Input: DAG based task 𝑡 generated on origin node 𝑁_origin.

BEGIN

(1)   Construct priority based task sequence 𝛽.

(2)   Do {

(3)         Choose first unscheduled subtask ST_𝑗 from 𝛽.

(4)         if (precedence level of ST_𝑗=1)

(5)         {

(6)           Pd_ld=0.

(7)         }

(8)         else if (precedence level of ST_𝑗−1! = precedence level ST_𝑗)

(9)         {

(10)         Pd_ld=RbK.

(11)  }

(12)         for (all nodes present in list 𝑙 of 𝑁_origin ).

(13)          {

(14)        compute ld^ST𝑗_𝑁 on node using (4) and store in list 𝑙

(15)         calculate Trt^ST𝑗_𝑋𝑁 on node using (2) and store in list 𝑙

(16)         if Wld^Old_𝑁≥Trt^ST𝑗_𝑋𝑁&&Wld^Old_𝑁≥Pd_ld

(17)          {

(18)              Calculate assumed workload Wld^ST𝑗_𝑁using (5)

(19)     }

(20)         else if Trt^ST𝑗_𝑋𝑁≥Wld^Old_𝑁&&Trt^ST𝑗_𝑋𝑁≥Pd_ld

(21)          {

(22)             Calculate assumed workload Wld^ST𝑗_𝑁using (6)

(23)  }

(24)         else if Pd_ld≥Trt^ST𝑗_𝑋𝑁&&Pd_ld≥Wld^Old_𝑁

(25)          {

(26)            Calculate assumed workload a Wld^ST𝑗_𝑁using (7)

(27)  }

(28)         Calculate Rb^ST𝑗_𝑁 for subtask ST_𝑗 and store in list 𝑙.

(29)       }

(30)        Find node 𝑅 for which Rb^ST𝑗_𝑁 is having smallest value and assign task to 𝑅.

(31)        Update value of Wld^Old_𝑅 in list 𝑙 on node 𝑅 and in list of all its direct neighbors.

(32)        if (precedence level of ST_𝑗=1∣∣ precedence level of ST_𝑗−1! = precedence level ST_𝑗)

(33)       {

(34)         RbK=Rb^ST𝑗_𝑅

(35)       }

(36)          else if (precedence level of ST_𝑗−1 = precedence level ST_𝑗)

(37)       {

(38)         if RbK≤Rb^ST𝑗_𝑅

(39)         {

(40)           RbK=Rb^ST𝑗_𝑅

(41)         }

(42)       }

(43)  }   while (there are unscheduled subtasks in 𝛽)

END

Output: Schedule for subtasks of DAG based task 𝑡.