Supervision : Alain GREINER

Co-supervision : WAJSBÜRT Franck

Système de fichiers scalable pour architectures manycores à faible empreinte énergétique

In this thesis we study the problems of implementing a UNIX-like scalable ?le system on a hardware cache coherent NUMA manycore architecture. To this end, we use the TSAR manycore architecture and ALMOS, a UNIX-like operating system. The TSAR architecture presents, from the operating system point of view, three problems to which we offer a set of solutions. One of these problems is speci?c to the TSAR architecture while the others are common to existing coherent NUMA manycore.
The ?rst problem concerns the support of a physical memory that is larger than the virtual memory. This is due to the extended physical address space of TSAR, which is 256 times bigger than the virtual address space. To resolve this problem, we modified the structure of the kernel to decompose it into multiple communicating units.
The second problem is the placement strategy to be used on the ?le system structures. To solve this problem, we implemented a strategy that evenly distributes the data on the different memory banks. The third problem is the synchronization of concurrent accesses to the ?le system. Our solution to resolve this problem uses multiple mechanisms. In particular, the solution uses an ef?cient lock-free mechanism that we designed, which synchronizes the accesses between several readers and a single writer.
Experimental results show that: (1) structuring the kernel into multiple units does not deteriorate the performance and may even improve them ; (2) our set of solutions allow us to give performances that scale better than NetBSD ; (3) the placement strategy which distributes evenly the data is the most adapted for manycore architectures.

2014-2016 Publications

• 2016
  • M. Karaoui : “Système de fichiers scalable pour architectures manycores à faible empreinte énergétique”, thesis, phd defence 06/28/2016, supervision Greiner, Alain, co-supervision : Wajsbürt, Franck (2016)
  • P.‑Y. Péneau, M. Karaoui, F. Wajsbürt : “Migration de processus pour un multi-noyau large échelle”, ComPAS 2016 - Conférence francophone d'informatique en Parallélisme, Architecture et Système, Lorient, France (2016)
  • M. Karaoui, P.‑Y. Péneau, Quentin L. Meunier, F. Wajsbürt, A. Greiner : “Exploiting Large Memory using 32-bit Energy-Efficient Manycore Architectures”, 10^th International Symposium on Embedded Multicore/Many-core Systems-on-Chip, Lyon, France, pp. 61-68, (IEEE) (2016)
• 2015
  • M. Karaoui, Quentin L. Meunier, F. Wajsbürt, A. Greiner : “GECOS : Mécanisme de synchronisation passant à l’échelle à plusieurs lecteurs et un écrivain pour structures chaînées”, Revue des Sciences et Technologies de l'Information - Série TSI : Technique et Science Informatiques, vol. 34, pp. 53-78, (Lavoisier) (2015)
• 2014
  • M. Karaoui, Quentin L. Meunier, F. Wajsbürt, A. Greiner : “Mécanisme de synchronisation scalable à plusieurs lecteurs et un écrivain”, Conférence en Parallélisme, Architecture et Systèmes, ComPAS 2014, Neuchâtel, Switzerland (2014)