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The Performance of µ-Kernel-Based Systems

The Performance of µ-Kernel-Based Systems

Hermann Härtig, Michael Hohmuth, Jochen Liedtke, Sebastian Schönberg, and Jean Wolter


Proceedings of the 16th ACM Symposium on Operating System Principles (SOSP), St. Malo, France, October 1997

Date: 10.1997


First-generation μ-kernels have a reputation for being too slow and lacking sufficient flexibility. To determine whether L4, a lean second-generation μ-kernel, has overcome these limitations, we have repeated several earlier experiments and conducted some novel ones. Moreover, we ported the Linux operating system to run on top of the L4 μ-kernel and compared the resulting system with both Linux running native, and MkLinux, a Linux version that executes on top of a firstgeneration Mach-derived μ-kernel.

For L4Linux, the AIM benchmarks report a maximum throughput which is only 5% lower than that of native Linux. The corresponding penalty is 5 times higher for a co-located in-kernel version of MkLinux, and 7 times higher for a userlevel version of MkLinux. These numbers demonstrate both that it is possible to implement a high-performance conventional operating system personality above a μ-kernel, and that the performance of the μ-kernel is crucial to achieve this.

Further experiments illustrate that the resulting system is highly extensible and that the extensions perform well. Even real-time memory management including second-level cache allocation can be implemented at user-level, coexisting with L4Linux.


  author = {Hermann H\"artig and Michael Hohmuth and Jochen Liedtke and Sebastian Sch\"onberg and Jean Wolter},
  title = {The Performance of Microkernel-Based Systems},
  booktitle = {Proceedings of the 16th ACM Symposium on Operating System Principles (SOSP)},
  address = {St. Malo, France},
  month = oct # "~5--8",
  year = 1997,
  url = {http://l4ka.org/publications/}