Testing Manycore Scaling with Simics
By Jakob Engblom
A few years ago, I did a Simics demo where I tested the scalability of a multithreaded program as the target hardware went from two to four to eight cores. Unfortunately, I could not take it beyond that point, since the hardware platform that I used simply did not allow for more than eight cores. Now, with the Simics Quick Start Platforms (QSP), the situation is different. I picked up the demo again, and pushed it to sixty (60) cores with ease.
The QSP platform that comes with Simics scales out to 128 processors by default (and more if you are willing to do some modifications to the model). It also comes with a Linux image that works for 128 processors, providing the infrastructure for testing threaded programs. Armed with this, I compiled my original pthread-based Linux program for the QSP, and ported my old demo scripts to the QSP – taking the chance to generalize things and add some new bells and whistles to the setup in the process.