Using Tracing Techniques to Investigate Performance Problems

Trying to soak up all the hardware resources available, or you're trying to reserve some for when youave spike and usage. O r, when you need it. And that's the distinction i've run into. The ibum 70, ten people, they built a whole box of hardware to watch the programm counter value on some instruction bus every cycle for seconds. That was the only way they could see what the programmes were really doing. And the same thing now, it's real hard to build low enough overhead tracing soft ware. You got lots of high overhead tracingsoft ware instead, and then you can't use it in a real time environment. I think the processes are surprisingly