% /hades/examples/performance/README

A few example designs to test (and or demonstrate) raw simulator
performance. Other good performance tests are the PIC processor
designs in /hades/examples/pic16c84.

o inv_chain10:   
                          A simple chain of ten inverters, driven by
                          a clock generator. Except for the wakeup-events
                          from the clock generator, this design will have
                          at most on event scheduled from the inverters.
                          Therefore, it allows to measure the raw simulation
                          speed with a very simple StdLogic1164 component.

                          Depending on the virtual machine (w/o JIT), we
                          have seend between 10.000 and 250.000 events/sec.
    
                          To get performance from the Hotspot VM, you may
                          need to stop and restart the simulation...


o incr_chain10:     
                          A chain of ten incrementers of 40 bits each, and
                          some logic to initialize the circuit. The design
                          is used to demonstrate the performance of simple
                          operations on StdLogicVectors.

o gates_and_counter:
                          Another inverter chain with some initialization
                          logic. This design doesn't need clock generator
                          wakeup events and may run even faster. However,
                          the counter component also stresses the graphics
                          capabilities of your VM - mainly setText() calls
                          and image bitblts.

                          Play with several 'repaint frequency' settings
                          to see how they affect simulation performance
                          and VM stability.





For comparison, hand-stopped tests with corresponding VHDL designs
and two leading commercial VHDL simulators gave the following results
on a Sun workstation (Ultra-1, 143MHz, 64Mbyte RAM, Solaris 2.51):

events/second:                    inv_chain10  incr_chain10

Synopsys VSS 1998.08:                 137.000        30.300

Cadence Leapfrog sv 2.60-s021:              -         9.800
                
Neither Synopsys nor Leapfrog offer 'glow mode' or animation. 
