I use the "Allow 3mb of memory for each Vuser" rule.
Your CPU running @ 100% with 5 Vusers is NOT a Loadrunner or machine problem, I have had 200 Vusers running on kit slightly more powerful. I would suggest it may be your application that is causing this.
Two more wild ideas:
- You use a lot of CPU intensive functions like RAND and no think time at all?
How many hits/sec or transactions/sec are you getting from your 5 VUsers?
- If antivirus is disabled?
Taking a step back. Which machine is showing 100% CPU? Is the host in question the Virtual user host? Is the host in question the Server hosting the WebLogic Application?
Items that I have seen cause 100% CPU in the past.
Running the entire test on one box (Controller + Virtual Users + Server under test)
Running on a Windows Host running an OpenGL screensaver (make sure your screensaver is blank). This applies to Virtual user hosts as well as the servers hosting the WebLogic app.
Running your virtual users on a host which cannot fill the available pipe (200Mhz host with a gigabit ethernet adapter). The VU host CPU is consumed by the NIC and Stack interrupy service requests. Usually a factor of 2x processor to fill a given pipe in WinTel universe (i.e. GigE would require a 2GHZ processor)