Running multiple Thread Groups sequentially in JMeter

Concerning consecutive execution of thread groups in test plan: simple check Run Test Group consecutively check-box on the Test Plan configuration screen:

1. Use e.g. Loop Controller for this:

   Thread Group
   Number of Threads = 1
   Loop Count = 1
     ...
     Loop Controller
     Loop Count = N
         HTTP Request
     ...
   

   or even schema without Loop Controller but not so flexible:

   Thread Group
   Number of Threads = 1
   Loop Count = N
     ...
     HTTP Request
     ...
   

2. Use Number of Threads property of standard Thread Group for this together with Ramp-Up Period property:

   Thread Group
   Number of Threads = N
   Ramp-Up Period = 0
   Loop Count = 1
     ...
     HTTP Request
     ...
   

   This will start N simultaneous threads executing same scenario.