Evaluating IA-32 web servers through simics: a practical experience

Nowadays, the use of multiprocessor systems is not just limited to typical scientific applications, but these systems are increasingly being used for executing commercial applications, such as databases and web servers. Therefore, it becomes essential to study the behavior of multiprocessor architectures under commercial workloads. To accomplish this, we need simulators able to model not only the CPU, memory and interconnection network but also other aspects that are critical in the execution of commercial workloads, such as I/O subsystem and operating system. In this paper, we present our first experiences using Simics, a simulator which allows full-system simulation of multiprocessor architectures covering all the topics previously mentioned. Using Simics we carry out a detailed performance study of a static web content server, showing how changes in some architectural parameters, such as number of processors and cache size, affect final performance. The results we have obtained corroborate the intuition of increasing performance of a dual-processor web server opposite to a single-processor one, and at the same time, allow us to check out Simics limitations. Finally, we compare these results with those that are obtained on real machines.