Hello, I have a question regarding the implementation of M5's Event Queue.
My current understanding of the simulator's event queue, is that there is currently only one main Event Queue in which all the corresponding simobjects place their scheduled events into this single queue. This is as opposed to having each SimObject have their own SelfEventQueue that feeds into the Main Event Queue (something that would lead towards parallelizing the simulator, not sure if this is currently being worked on?) Anyways, In reading through the comments of the source code (eventq.hh lines: ~100) The comments describe the event queue as a linked list of linked lists such that each "bin" (i am assuming by bin it refers to a linked list) that is defined by when+priority (where when is the timestamp==cycle) in which the scheduled event should be executed. >From my understanding, the way this is structured is such that multiple scheduled events can have the same 'when' timestamp, depending on the current cycle time + the latency derived by the scheduling SimObject. So from a storage perspective, i can see how several events might coincidentally have the same 'when' and possibly the same defined priority, but in terms of execution, how does the event queue decide which to execute? Because theoretically only one event can be set for execution per cycle (although many instructions for different events may be in execution simultaneously due to Instruction Level Parallelism?) In the case, that the different events do not have the same 'when' timestamp, that means then each bin essentially contains only one element (event), and if this latter case is how it is actually set up, then what is the need to have multiple linked lists where each corresponds to a bin if there is only one element? I apologize in advance for the long, detailed, and possibly confusing question, and would appreciate any help. Thanks. Malek The event queue is described as a linked list of linked lists. _______________________________________________ m5-users mailing list [email protected] http://m5sim.org/cgi-bin/mailman/listinfo/m5-users
