Are you refering to VM startup time ?? As for as my understanding, you cannot get VM startup time from CloudSim.  Theoretically VM startup time has multiple impact factors and CloudSIm doesn't cover those. Some of users suggested me to use simple timers in VM of CloudSim, but that was not good enough.  Its better to create a testbed with Openstack and measure it. 

Thank you for the reply.

I am a beginner of cloudsim. So I want to implement some load balancing algorithms in cloudsim. When I was implementing min-min algorithm , I didn't get how to calculate ready time, while calculating the completion time:

Completion timeij=Execution Timeij+ Ready timej

where, Ready Timej - Ready time of resource Rj.

So I too thought it is the startup time of VM. But I have seen many papers that have modified min-min algorithm in cloudsim only. If you get any idea of calculating ready time for the calculation of the completion time please let me know.

And can you please suggest me which is better among Openstack or a simulator for cloud computing load balancing?

Hi, 

According to the first part of your question, the start-up time of VM is the finish time of the last executed task in this VM. To calculate the execution time, yes you can divide the length of task by processing speed of VM (usually in terms of MIPS).

Thank you Alboaneen.

In CloudSim all tasks are start at 0 so by default all Vms start time will 0 but if you want to change the ready time of each task then you must model your own workload model, for that u can use exponential distribution or hyper exponential distribution for task execution time and u can use random function to generate different arrival time of each task.