round robin cpu scheduling » gate fundas
Post on 01-Nov-2015
9 Views
Preview:
DESCRIPTION
TRANSCRIPT
-
05/08/2015 RoundRobinCPUSchedulingGATEFundas
http://www.gatefundas.com/roundrobincpuscheduling/ 1/5
ALLGATERELATEDQUERIES,ARTICLESANDDISCUSSIONS
Search
GATEFundas
ShortestRemainingtimefirst(SRTF)CPUscheduling
MiscellaneousexamplesonCPUschedulingwhereprocessesspendsometimedoingCPUandsometimedoingI/O
OperatingSystem Addcomments
RoundRobinCPUSchedulingOct112014
RoundRobinschedulingismostpracticalschedulingalgorithmsusedforschedulingtheprocessesontotheCPU.Inthisalgorithmeveryprocessisexecutedforatimequantum(timeslice)andthenpreemptedtogivechancetootherprocess.
Criteria:Timequantum(Timeslice),arrivaltimeMode:Preemptive
Flowchartofroundrobinscheduling
Example1:Findaverageresponsetime,averageturnaroundtimeandaveragewaitingtime
P.No. Arrivaltime Bursttime
1 0 4
2 1 5
3 2 2
4 3 1
5 4 6
6 6 3
Timequantum=2
Solution:Inroundrobinschedulingwehavetomaintainonereadyqueueinwhichprocessesarekeptandexecutedinthesameordertheyentered.
Bethefirstofyourfriendstolikethis
GATEfundas129likes
LikePage Share
Search
Search
Subnetting
IPaddressing2
IPaddressing1
SolutionsofSomepreviousyearGATEquestionsonCPUscheduling
PrioritybasedScheduling
RecentPosts
RecentComments
Home ComputerNetworks TheoryOfComputation DBMS OperatingSystem Electronics&Communication
Fe
edba
ck
-
05/08/2015 RoundRobinCPUSchedulingGATEFundas
http://www.gatefundas.com/roundrobincpuscheduling/ 2/5
Readyqueue:emptyP1arrivesatt=0Readyqueue:P1soaccordingtoflowchartB.T
-
05/08/2015 RoundRobinCPUSchedulingGATEFundas
http://www.gatefundas.com/roundrobincpuscheduling/ 3/5
2 4 6
3 3 7
4 1 9
5 2 2
6 6 3
Timequantum=3
Solution:FollowingtheexplanationofaboveexampleGANTTchartandreadyqueueofthisexampleareasfollows
ReadyQueue:P4,P5,P3,P2,P4,P1,P6,P3,P2,P4,P1,P3
P4 P5 P3 P2 P4 P1 P6 P3 P2 P4 P1 P3
0 1 4 6 9 12 15 18 21 24 27 303233
Responsetime=firstresponsetimearrivaltimeTurnaroundtime=completiontimearrivaltimeWaitingtime=turnaroundtimebursttime
P.No. Arrivaltime Bursttime Completiontime Turnaroundtime Waitingtime responsetime
1 5 5 32 27 22 10
2 4 6 27 23 17 5
3 3 7 33 30 23 3
4 1 9 30 29 20 0
5 2 2 6 4 2 2
6 6 3 21 15 12 12
Total=128 Total=96 Total=32
AverageResponsetime=32/6=5.3Averageturnaroundtime=128/6=21.3Averagewaitingtime=96/6=16
Example3:Consider4processesP1,P2,P3,P4allarrivinginthesameorder.Thebursttimerequirementsoftheprocessesare4,1,8,1respectivelythenwhatisthecompletiontimeofprocessP1.AssumingroundrobinschedulingwithTimeQuantum=1a)7b)8c)9d)10
Solution:Givenallprocessesarriveinsameordersotakearrivingtimeofallprocessesas0
P.No Arrivaltime Bursttime
1 0 4
2 0 1
3 0 8
4 0 1
AsarrivaltimesofalltheprocessesaresamesofirstplacetheprocessesinreadyqueuebasedonlowestprocessnumberfirstReadyQueue:=P1,P2,P3,P4Nowproceedinthesamewayasexplainedabove.
-
05/08/2015 RoundRobinCPUSchedulingGATEFundas
http://www.gatefundas.com/roundrobincpuscheduling/ 4/5
P1 P2 P3 P4 P1 P3 P1 P3 P1 P3
0 1 2 3 4 5 6 7 8 9
CompletiontimeofP1is9
Example4:[GATE2012]Considerthreeprocessesshowninthetable
Process Arrivaltime Bursttime
P1 0 5
P2 1 7
P3 3 4
ThecompletionorderoftheprocessesunderthepoliciesFCFSandroundrobinwithtimequantumof2units(a)FCFS:P1,P2,P3RR:P1,P2,P3(b)FCFS:P1,P3,P2RR:P1,P3,P2(c)FCFS:P1,P2,P3RR:P1,P3,P2(d)FCFS:P1,P3,P2RR:P1,P2,P3
Solution:
P1arrivesatt=0ReadyQueue:P1forP1B.T
-
05/08/2015 RoundRobinCPUSchedulingGATEFundas
http://www.gatefundas.com/roundrobincpuscheduling/ 5/5
2014GATEFundas CustomisedbyGATEFundasteam
Examplesonlosslessjoindecomposition2commentsayearago
nishantagrawal25AC+isacbdegfororiginaldependencysetbutwhenyouwilllookindecomposedrelationitisonly
MinimalcoverorCanonicalcoverofgivenFDset2commentsayearago
nishantagrawal25GladtoknowthattheseexampleshelpedyouThanksforpointingoutthetypo,It'scorrectednowPleasetellif
ALSOONWWW.GATEFUNDAS.COM
2Comments www.gatefundas.com Login1
Share SortbyBest
Jointhediscussion
Reply
meli 7monthsagoAreusurethat?MynoteshowTurnarround=completesubmited..notTurnarround=completearrival
Reply
nishantagrawal25 7monthsagoMod >meliSubmittedandarrivalmeanssamethinghere...SubmittedmeanswhenjobissubmittedtotheCPUwhichissameasarrivaltime
WHAT'STHIS?
Subscribe AddDisqustoyoursited Privacy
Recommend
Share
Share
top related