Supervision : Pierre SENS

Co-supervision : SOPENA Julien

A kernel cooperative cache for virtualized environments

With the advent of cloud architectures, virtualization has become a key mechanism for ensuring isolation and flexibility. However, a drawback of using virtual machines (VMs) is the fragmentation of physical resources. As operating systems leverage free memory for I/O caching, memory fragmentation is particularly problematic for I/O-intensive applications, which suffer a significant performance drop. In this context, providing the ability to dynamically adjust the resources allocated among the VMs is a primary concern.
To address this issue, this thesis proposes a distributed cache mechanism called Puma. Puma pools together the free memory left unused by VMs: it enables a VM to entrust clean page-cache pages to other VMs. Puma extends the Linux kernel page cache, and thus remains transparent, to both applications and the rest of the operating system. Puma adjusts itself dynamically to the caching activity of a VM, which Puma evaluates by means of metrics derived from existing Linux kernel memory management mechanisms. Our experiments show that Puma significantly improves the performance of I/O-intensive applications and that it adapts well to dynamically changing conditions.

2012-2016 Publications

• 2016
  • M. Lorrillere : “Caches collaboratifs noyau adaptés aux environnements virtualisés”, thesis, phd defence 02/04/2016, supervision Sens, Pierre, co-supervision : Sopena, Julien (2016)
• 2015
  • M. Lorrillere, J. Poudroux, J. Sopena, S. Monnet : “Gestion dynamique du cache entre machines virtuelles”, Conférence d'Informatique en Parallélisme, Architecture et Système, Compas'2015, Lille, France, pp. 1-10 (2015)
  • M. Lorrillere, J. Sopena, S. Monnet, P. Sens : “Puma: pooling unused memory in virtual machines for I/O intensive applications”, SYSTOR'15 - 8^th ACM International Systems and Storage Conference, Haifa, Israel, pp. 1:1-1:11, (ACM) (2015)
  • M. Lorrillere, J. Sopena, S. Monnet, P. Sens : “Conception et évaluation d’un système de cache réparti adapté aux environnements virtualisés”, Revue des Sciences et Technologies de l'Information - Série TSI : Technique et Science Informatiques, vol. 34 (1-2), pp. 22, (Lavoisier) (2015)
• 2014
  • M. Lorrillere, J. Sopena, S. Monnet, P. Sens : “PUMA: Un cache distant pour mutualiser la mémoire inutilisée des machines virtuelles”, ComPAS'2014 : Conférence d'informatique en Parallélisme, Architecture et Système, Neuchâtel, Switzerland, pp. 1-12 (2014)
• 2013
  • M. Lorrillere, J. Sopena, S. Monnet, P. Sens : “Vers un cache réparti adapté au cloud computing”, Conférence d'informatique en Parallélisme, Architecture et Système (ComPAS'2013) - 9^e Conférence Française sur les Systèmes d'Exploitation (CFSE'13), Grenoble, France, pp. 1-12 (2013)
• 2012
  • L. Millet, M. Lorrillere, L. Arantes, S. Gançarski, H. Naacke, J. Sopena : “Facing peak loads in a P2P transaction system”, Proceedings of the First Workshop on P2P and Dependability (P2PDEP'12), P2P-Dep '12, Sibiu, Romania, pp. 1-7, (ACM) (2012)