Slow and fast simulators

I am not talking about the benchmarks that you do on different simulators and classify them as slow and fast simulators. I am talking about running the simulators on debug and high performance modes.

Play with your simulator switches and understand how you can run it at different speeds. Its like running your car at different speeds using different gears. You need to change the gear based on power and speed requirements. Similarly you need to change the simulator options based on verification requirements.

Why you need this debug and performance mode?
Generally all the simulators run on high performance mode by default. In this mode the simulator does not have to instrument the code and log many details. So this performance mode enables the simulator to run at its highest speed. But in this mode, you cannot debug your design through line stepping, break point setting, delta cycle analysis, wave form dumping etc. Always
run your regression tests on high performance mode. Finally rerun your failing testcases on debug mode.

I have seen many of my customers who run the simulator on debug mode which is normally 2X slower than running on performance mode, for their regressions. Sometimes they enable waveform dumping too that again slows down the simulator. Usually verification engineers use the scripts written by some PERL or shell script experts. Only few guys want to take a look on the simulator options that have been used in the script, before running the regressions.

As a smart engineer, you should always scan your script before using it. Talk to CAD team, EDA guy and the script owner and make sure that you understand the simulator options and script very well. Even if you are so busy with your project verification, still you have to spend some time on analyzing the scripts.