I have a 2 part question. In SilkPerfomer we have Virtual Users that simulate the transactions what are they called in LoadRunner?
The second question refers to how they relate to real users in concurrency (I know a Virtual User can do more transactions over "n" but is their a formula that LoadRunner uses for concurrent users)?
The reason I ask this is because I am being asked to compare my test runs in SP with previous run made by another party using LR. They did a 200user test and managed to get 1500 transaction done in a time period and then stated that the system should be able to handle 1500 concurrent users. My understanding of SP is that the only way to know if the system can truly handle 1500 concurrent users is to place 1500 concurrent users on the system, is this correct. I am being asked to justify my finding against the previous test and just want to know if LR has some feature that justifies the theory used previously.
But in the end doesn't it all come down to BEER? Beer is the ultimate answer to all questions in the universe so yes the answer to your question is BEER.
Transactions in SilkPerformer are more analogous to functions, such as the entire iteration of a business process which is contained within a function "Action()" as an example.
it would be useful to know which graph you are looking at, but in general you have the graph of running virtual users which may or may not correspond to "concurrent" in your context. On the plus side, as compared to SilkPerformer, every timing record is kept uniquely in an open databased format. The results of an analysis session are either stored in An Access formatted database or in a Microsoft SQL Server formatted database, so you can open the database, look for a table called event_meter and look at the open timing records for a given time offset into the test.
One item you may be able to graph that could correspond to concurrent active sessions, as opposed to those which are in inter-iteration sleep, is the main function associated with the business process. The default name for this in most LR scripts is Action(), but the developer could change it to anything he|she wanted. In the run time settings the setting much be checked for treating each action as a transaction (timing record), then you could simply graph the number of items/sec associated with the core business process function. This should get you the "active" sessions doing work at any given moment, which is going to be less generally than the users which are in "Run" mode.