Team Compsys

Overall Objectives
Scientific Foundations
New Results
Contracts and Grants with Industry
Other Grants and Activities

Section: New Results

On-Chip Traffic Analysis

Participants : Patrice Abry [ ens -l yon, Physics Lab ] , Antoine Fraboulet, Tanguy Risset, Antoine Scherrer.

This work is part of the PhD of Antoine Scherrer, co-funded by stm icroelectronics and the cnrs . The goal is to (semi-)automatically generate a traffic generator from an execution trace of a SoC ip . This traffic generator can then be used to prototype noc performances in various configurations. We work on this topic in relation with stm icroelectronics. We are also working in collaboration with Patrice Abry, from the Physics laboratory of ens -l yon. Patrice Abry ( ) is a worldwide expert in traffic modeling with self-similar processes. Many results have been published in 2006 on this topic.

First, the analysis and synthesis of long range dependent processes are now fully operational. These tools have been applied to network anomalies detection, a work published in IEEE Transactions on Dependable and Secure Computing (TDSC) [4] . The technique developed for long range dependence synthesis is potentially applicable to many scientific domains.

Second, the complete noc prototyping environment is now operational. It has been implemented in the cycle-accurate SoC simulation environment SoCLib. It consists in:

All these components have been integrated in a semi-automatic noc prototyping environment . The designer only manually specifies the organization of the platform to be simulated (in a user-friendly format) and the choice of generation: traces are replayed or a stochastic traffic (according to some specified statistical characteristics) is generated. Traffic analysis has been performed on embedded applications (mp 3, mpeg , jpeg ), running on a multi-processor SoC interconnected with the Spin or DSpin noc (developed at LIP6). The original features of this environment are:

  1. The availability in such a cycle-accurate simulator of a complete set of tools to analyze and synthesize traffic with particular second order statistical properties.

  2. The automatic decomposition of a given traffic trace in phases with stationary statistical behavior (using a technique developed for software prototyping).

  3. The fact that the traffic generator can be configured independently of the network (it is latency aware), which makes possible to program the traffic generator from a trace obtained on a simple platform (no noc ) and use this program for all the noc configurations to be tested. This features improves the speed of the complete prototyping flow.

These experiments have been published in ASAP [16] and CODES/ISSS [17] . The complete work is described in Antoine Scherrer's PhD thesis.