An Application-Level QoS Control Method Based on Local Bandwidth Scheduling

Algorithm 2

Bandwidth dynamic scheduling method (the second allocation).

Input: The unallocated tokens after the first allocation ()

Output: The second token allocation policy ()

(1) SecondAllocation ()

(2) Obtain the running Web processes not listed in

(3) the priority database and mark them as

(4) Initialize the second allocation policy

(5) FOR i=0 to COUNT()-1 // Retrieve each process

(6) Mark the bucket of process in as B_i

(7) IF ((B_i) < (B_i)) // Bucket is not full

(8) // T_i is the remaining capacity of B_i

(9) T_i = (B_i) - (B_i)

(10) Initialize the allocation policy (allocation) for B_i

(11) // Set the BUCKET member of allocation (token ID)

(12) allocation.BUCKET = B_i

(13) // Set the TOKEN member of allocation (token count).

(14) // This value may be modified in the following steps.

(15) allocation.TOKEN = allocation.TOKEN + T_i

(16) Add allocation into the second allocation policy

(17) Delete allocated tokens from

(18)

(19)

(20) // Calculate how many tokens each process can get

(21) // using average allocation policy

(22) IF (COUNT() > 0)

(23) AVE = COUNT() / COUNT()

(24)

(25) // Loop through to update the token count for

(26) // each allocation

(27) FOR k=0 to COUNT()-1

(28) Mark the item of as A_k

(29) // update the token count using the average value

(30) A_k.TOKEN = A_k.TOKEN +

(31) MIN((A_k) - (A_k), AVE)

(32) Delete the allocated tokens from

(33)

(34) IF (COUNT() == 0) // Token allocation finished

(35) RETURN

(36)

(37) ELSE // Still have unallocated tokens

(38) // Try to allocate the remaining tokens to all the running

(39) // Web processes regardless of their existence in the

(40)// priority database through token borrowing

(41) Get all the running Web process L_p and sort it in descending order of priority

(42) FOR j=0 to COUNT(L_p)-1

(43) Mark the bucket of the j_th process in L_p as M_j

(44) IF ((M_j) < (M_j)) // Bucket is not full

(45) Get the maxBorrow of the current bucket ()

(46) IF ( > 0) // Can borrow more tokens

(47) // T_j is the remaining capacity of M_j

(48) T_j = (M_j) - (M_j)

(49) Initialize allocation for M_j

(50) // Set the BUCKET member of allocation (token ID)

(51) allocation.BUCKET = M_j

(52) // Set the TOKEN member of allocation (token count)

(53) allocation.TOKEN = allocation.TOKEN +

(54) MIN(COUNT(), T_j, )

(55) Add allocation into the second allocation policy

(56) Subtract the count of allocated tokens from the token

(57) borrowing parameter ()

(58) Delete the allocated tokens from

(59) IF (COUNT() == 0) // Token allocation finished

(60) RETURN

(61)

(62)

(63)

(64)

(65)

(66) RETURN null

(67)