SJF cloudlet scheduling

[hajar eddaibouni]

Hi,

 

 I am a beginner in CloudSim ,I want to implement SJF scheduling algorithm for cloudlet. I Know that I have to make changes in broker code but i don't know how. Plz help!!

Thanks,

Hajar.

[Mario Henrique Souza Pardo]

Hajar,

   you need to do changes in submitCloudlets method in DatacenterBroker. 

   Good luck!!

       Regards!

Mário Pardo

ICMC-USP / São Carlos / Brazil

mhp...@icmc.usp.br

Research Gate Profile [LINK]

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[hajar eddaibouni]

Hi Mário Pardo,

Thanks for your reply.  Now I want to calculate the burst time, i want to sort the list of cloudlet by burst time(concept of SJF) , now i can just sort the cloudlets by length using sort method of cloudsim!!

 can you tell how I can calculate the burst time of a cloudlet in cloudsim??!!

Thanks,

Regards.  

[Mario Henrique Souza Pardo]

Dear Hajar,

   congrats by your Success! =)

  to calculate this bursting time, what is your plan? I'm not sure if I understand the purpose  SJF scheduling... do you will base your calculation in the task length using cloudlet received list in broker? 

Explain better your idea to we can try to help with implementation, please. 

Regards!

Mário Pardo

ICMC-USP / São Carlos / Brazil

mhp...@icmc.usp.br

Research Gate Profile [LINK]

[hajar eddaibouni]

Hi Mário ,

Thanks for your help,

The concept of SJF algorithm is based on sorting the list of tasks by their estimated execution time, so the task having a smaller time of executing is the first to be executed.

the problem now that i don't now how to calculate that estimated execution time in Cloudsim, can you help me plz!!

Regards.

[Mario Henrique Souza Pardo]

Dear Hajar,

   if you have heterogeneous tasks (with different lengths) maybe you can handle this situation as following:

   - before the broker submit cloudlets you can do an ordered list (by task length) from original cloudletList using some ordering algorithm like Bubble Sort, etc. Then, you need analyse all VM instances (getting vmCreateList) and calculating the execution time for each cloudlet. To do this calcultation proceed as: 

   Step 1: Try to get each Virtual Machine queue length, get the lower queue for cloudlet at hand. (to do this I don't know what is the difficult but, you can try to create a special method in CloudletScheduler that you are using in VMs from your simulation program).

   Step 2: To calculate the execution time try something like: double executionTime = cloudlet.getCloudletLength() / (vm.getMips()*vm.getNumberOfPes());

   Step 3 and etc: follow your project rules to scheduling!!

   I hope that tips can be helpful for you, fellow!

   Have a nice coding!

    Regards!

Mário Pardo

ICMC-USP / São Carlos / Brazil

mhp...@icmc.usp.br

Research Gate Profile [LINK]

2014-03-09 10:24 GMT-03:00 hajar eddaibouni <hajar.ed...@gmail.com>:

Dear Mário ,

The concept of SJF algorithm is based on sorting the list of tasks by their estimated execution time, so the task having a smaller time of executing is the first to be executed.

the problem now that i don't now how to calculate that estimated execution time in Cloudsim, can you help me plz!!

Regards.

For more options, visit https://groups.google.com/d/optout.

[hajar eddaibouni]

Hi Mario, 

Thank you for your help, i can now sort the list of cloudlet by their length. Now I want to implement the Round Robin algorithm , but i don't know where to start because the concept of Round Robin is totally different from SJF.

The concept of roun robin is here: http://tanmayonrun.blogspot.com/2011/12/explain-and-solve-round-robin-rr-of.html

I don't know how to implement it in cloudsim,help me plz. 

[Mario Henrique Souza Pardo]

Hi Hajar,

   CloudSim default broker scheduling algorith is a single Round Robin. Can't you use it? If you want to use some kind of "quantum" for each cloudlet on Vm, so, I recommend you to use TimeShared classes like your strategy, because the RR Algorithm is ready for use in DatacenterBroker.

   Try to make some tests and give us your feedback.

   Have a nice coding buddy!

      Regards!

Mário Pardo

ICMC-USP / São Carlos / Brazil

mhp...@icmc.usp.br

Research Gate Profile [LINK]

[hajar eddaibouni]

Hi Mario,

Thank you for your help, so after making some tests and some googling i find that if i use CloudletSchedulerTimeShared for Vm/Cloudlet it would act like roundrobin algorithm but I have still two questions:

1- how the timeshared in cloudsim work, there is no variable that represent a time slice or quantum, so how the concept of round robin is verified in cloudsim?

2- I want to calculate the wating time and then compare the three scheduling algorithms (SJF, RR, FCFS) i used the method getWatingTime() in FCFS and SJF and it works, but in RR the result is always 0.0, i can't understand why?

Thank you & Regards.

[hajar eddaibouni]

Any Help plllz !!!!

[jyoti jha]

Hi Hajar,

i am doing priority based round robin scheduling, i need to do following things

1)assign the priority to vms based 

2) schedule cloudlets on vms(according to priority)

3) if vm gets overloaded move to next vm

4) calculate the total time.

please help me out, if possible let me know d changes you have done in cloudsim so that i can have an idea.

[Mario Henrique Souza Pardo]

Hi Hajar,

   sorry for the delay in reply for you.

   first, I would like to inform that the effect of Round Robin scheduling for the tasks is caused for the algorithm RR implemented on method submitCloudlets(). So, if you apply CloudletSchedulerSpaceShared or CloudletSchedulerTimeShared the task scheduling policy will be the same because it's a broker activity.

1- Answer: I have made a test to show you using CloudSimExample7.java file. In this file I just change the command line:

    vm[i] = new Vm(idShift + i, userId, mips, pesNumber, ram, bw, size, vmm, new CloudletSchedulerTimeShared());

   ...from createVm() method for this other one:

vm[i] = new Vm(idShift + i, userId, mips, pesNumber, ram, bw, size, vmm, new CloudletSchedulerSpaceShared());

  ... and then I performed and get the output report from CloudSim. The following output is using CloudletSchedulerTimeShared:

Cloudlet ID STATUS Data center ID VM ID Time Start Time Finish Time

0 SUCCESS 2 0 320 0,1 320,1

1 SUCCESS 2 1 320 0,1 320,1

2 SUCCESS 2 2 320 0,1 320,1

3 SUCCESS 2 3 320 0,1 320,1

4 SUCCESS 2 4 320 0,1 320,1

5 SUCCESS 2 0 320 0,1 320,1

6 SUCCESS 2 1 320 0,1 320,1

7 SUCCESS 2 2 320 0,1 320,1

8 SUCCESS 2 3 320 0,1 320,1

9 SUCCESS 2 4 320 0,1 320,1

Pay attention to the execution time (320 seconds) and to the Start Time. The execution time to the task should be 160.00 if it were executing alone in the VM, but how we now, each VM receveid 2 tasks in this example, so, the simulator share the time of VM in two slices, dividing the CPU capacity equally. This is the effect of TimeShared in the simulator.

Let's see what happens with the results when I change it for CloudletSchedulerSpaceShared:

Cloudlet ID STATUS Data center ID VM ID Time Start Time Finish Time

0 SUCCESS 2 0 160 0,1 160,1

1 SUCCESS 2 1 160 0,1 160,1

2 SUCCESS 2 2 160 0,1 160,1

3 SUCCESS 2 3 160 0,1 160,1

4 SUCCESS 2 4 160 0,1 160,1

5 SUCCESS 2 0 160 160,1 320,1

6 SUCCESS 2 1 160 160,1 320,1

7 SUCCESS 2 2 160 160,1 320,1

8 SUCCESS 2 3 160 160,1 320,1

9 SUCCESS 2 4 160 160,1 320,1

Pay attention again over values of execution time and start time. As we can see, the execution time decrease to half beucase the SpaceShared policy handle the tasks scheduling in VM level in a different way. Once a task get the CPU it will execute until the end, it means that this kind of policy run like a HPC application behavior. So, the CPUs from VM aren't shared between the tasks.

What's better? Depends of your scenario and application you want to emulate in the simulation.

2 - Well, I guess that you get 0.0 values in the return because you're using the CloudletSchedulerTimeShared, I have made a test in my computer and with Time Shared policy the result is exactly it. The cause of it is the cloudlets aren't waiting in the queue of VM to start, when its arrival in the VM they are started immediately, and then you have a 0.0 value in the waitingTime. Try to change for SpaceShared and give us your feedback.

   

   Hope that tips can be helpful!

         Regards!

Mário Pardo

ICMC-USP / São Carlos / Brazil

mhp...@icmc.usp.br

Research Gate Profile [LINK]

[hajar eddaibouni]

Hi Mario,

Thank you very match, I tested the CloudletSchedulerSaceShared and now i have a waiting time different from 0.0,

Plzz I have another question, now when i use cloudletSchedulerSpaceShared for FCFS and RoundRObin i have the same result , for FCFS i didn't make any changes in datacenterbroker Class because i found that it execute the cloudlets according to their submission Time ( the same concept of FCFS), and before you said that to implement The Round Robin algorithm i have just to use the default datacenterBroker class so the same way i used for FCFs an in the end i have of course the same result!!!!

Can you help me in how to implement FCFS and RoundRobin submitCLoudlet function in datacenterBroker class??  

[Mario Henrique Souza Pardo]

Hi Hajar,

   please, take a look at submitCloudlets method and pay attention to that code. You will percept that code performs as following: if a cloudlet has a vmID setted inside it, it's just sent to the VM which ID was assigned. And when a cloudlet doesn't have a VM ID setted, so, the code performs a cyclic alternation (is the same as Round Robin) sending each cloudlet to a different VM as a rotation algorithm.

   To create a different perspective to FCFS and Round Robin you need to alter this code providing a new form to tasks handling otherwise will appear as the algorithm when you execute you simulation.

   Hope that these ideas help you to get success in your implementation!

   Regards!

Mário Henrique de Souza Pardo / PhD Candidate

University of São Paulo / Institute of Mathematical and Computer Science (ICMC)

Laboratory of Distributed Systems and Concurrent Programming (LaSDPC)

São Carlos / SP / Brazil

mhp...@icmc.usp.br

Research Gate Profile [LINK]

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[Deepika Agrawal]

hie.. i need code of scheduling algorithm. as I am running shortage of time and also i am not efficient in java. Pls help me.

[Nootan Verma]

Hello Hajar, 

I m also beginner to CloudSim, working on task scheduling policies. I need ur help.. And i need the SJF code..plz help.

[amit vyas]

any have code shortest job first  cloudsim than post it

[amit vyas]

code for Backfill algorithm with priority base job scheduling

[Rubee Tandan]

Hello Mario and other group members,

I need help, I have to find arrival rate of cloudlets, and I don't know how to do it. Can you guys please help me?
Please reply as soon as possible.
Thank you

[Rubee Tandan]

11:16 AM (28 minutes ago)

Dear Mario and other group members,
I need the code for FCFS, SJF, ROUND ROBIN can any one help me?
please send me the codes if it is possible and if anyone have.
Any code will work i need something please help me.
My mail id is rubee2...@gmail.com, please send me the codes.

[Nikhil Dhakal]

Hi there,
You can find a tutorial for SJF implementation in youtube by SuperwitsAcademy. https://youtu.be/YFRtURmgHSQ?list=PLGe95EHDPn-X5Opz5xB-3rUnqr_PXOOnv

As for FCFS the cloudsim examples follow FCFS task scheduling.

[Rubee Tandan]

thanks a lot for your reply,

I implemented SJF, and FCFS but when i am tring to get the waiting time by getWatingtime() method I got 0 for every cloudlet and in this i was using timeshared mode.

When I change timeshare to space share I got different waiting time from 0 but I created 2 vm but only one was taking so the cloudlets which got other vm is not executing. 

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Thanks & Regards

Rubee Tanden

ME

CSA

Indian Institute of Science,Bangalore 

[Vikram Patalbansi]

Please add me in this group. I am doing research on cloud computing

[mohammad jomaa]

Hi  Vikram Patalbansi ,

i advise you to use cloudSim plus , i think you will find more Example on everything that you want .

R's

jomaa 

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