( ESNUG 412 Item 14 ) ------------------------------------------- [05/22/03]

Subject: ( SNUG 03 #6 ) An App Note On How To Speed Up Your ModelSim Runs

> We recently did a comparison of VCS and ModelSim SE.  We were attracted to
> the substantial cost savings the ModelSim offers.  We've tested them both
> with our latest Verilog design.  We've compared VCS version 6.1 against
> ModelSim SE 5.7a (their latest I believe) on a Linux PC box (AMD 1.67 GHz,
> 2GB phys mem, Red Hat 6.2) and found:
>
> (a) design compile time and memory usage:
>
> The ModelSim SE compiles much faster than VCS.  But it turns out that much
> of the "real" compilation occurs when you launch the simulator (vsim).
> The compiler (vlog) appears to be a light source code elaborator.  However
> the SE took between x2-x3 the memory of VCS during compilation.
>
> (b) simulation runtime and memory usage:
>
> The simulation runtime between the SE and VCS varied based on the size of
> the test, but on the average SE took x5 longer to run, and took x3 the
> memory of VCS.
>
>     - Joon Lee
>       SafeNet, Inc.


From: Joe Rodriguez <joer=person company=model naught pawn>

Hi John,

I am a Technical Marketing Engineer in the ModelSim group at Mentor.  I
appreciate all the comments in your postings.  I wanted to let everyone know
that ModelSim Verilog's default configuration is for maximum visibility.  It
has compile options for higher performance.  The main ModelSim performance
optimization is the +opt Verilog compiler switch.  There are just a few
considerations to keep in mind depending if you are running mixed HDL, or
pure Verilog.  Enclosed is our App note that details how to run ModelSim
faster.

    - Joe Rodriguez
      Model Tech                                 Portland, OR


  [ Editor's Note: Joe's app note is #45 of DeepChip Downloads  - John ]