Stress Testing The FreeBSD Kernel

With Peter Holm

In order to assure high quality in the FreeBSD kernel, with regards to panics, Peter Holm has been working on provoking, reporting and fixing kernel bugs.

This talk will describe the reasoning behind this special interest, how it is done and what it has achieved.

In order to stress test a kernel I have used four different aproaches, all involving small and very simple test programs:

Introduce as much randomness as possible in the tests, with regards to number of invocations, startup delay and test program mix
Introduce a few test programs to produce a background load of VM usage and network IO
Use random data as input
Modify legal data, by making random changes

With the release of FreeBSD 6.0 in November 2005 my work peaked with more than 150 (non unique) bug reports that year. All bugs found by stress testing were fixed by the FreeBSD community in an outstanding bug fix marathon before the 6.0 release.

Peter Holm's first contact with UNIX was in 1990 at Dansk Data Elektronik A/S, where he later gained insight in the QA process for a UNIX kernel. Started working with FreeBSD in 1995 and has been active (on and off) since 1999 with stress testing the kernel. For the last eight years he has been working as a freelance consultant.

Sidst opdateret: Tuesday, January 17, 2006