The SMTSIM Multithreading Simulator was written by Dean M. Tullsen with significant assistance from Jack Lo, Gun Sirer and (unbeknownst to him) Jim Larus.

Although Susan Eggers, Hank Levy, Joel Emer, and Rebecca Stamm never actually got their hands dirty in the code, they each influenced parts of it.

This code is provided "as is" with no promise of support whatsoever, but please do send bug reports (especially solved bugs!) to me.

When using the simulator to produce published research, please cite it with:

Simulation and Modeling of a Simultaneous Multithreading Processor,
D.M. Tullsen,In the 22nd Annual Computer Measurement Group Conference,
December, 1996


Simultaneous Multithreading: Maximizing On-Chip Parallelism, D.M. Tullsen,
S.J. Eggers, and H.M. Levy, In 22nd Annual International Symposium on
Computer Architecture, June, 1995. (also reprinted in 25 Years of the
International Symposia on Computer Architecture: Selected Papers, 1998, if
you'd prefer).

The SMTSIM simulator only runs on Compaq/Digital Unix Alphas. Please let me know if you successfully port it to another system.  It runs unmodified (but compiled with a couple of specific flags) Alpha object code.

Here it is:  SMTSIM version 1.0

When you do take the simulator, please drop me a note so I can keep track of who has it.

The latest rewrite of this simulator (without which I would not be distributing it at all) was funded
by NSF Career Award MIP-9701708.

If you have comments or suggestions, email me at tullsen(a)