stress2 is now in projects

John Baldwin jhb at
Wed Jan 21 06:19:28 PST 2009

On Sunday 18 January 2009 3:12:02 pm Bakul Shah wrote:
> Allowing a user to specify the random seed (and *always*
> reporting the random seed of every test) can't hurt and it
> may actually gain you repeatability in some cases.  Most bugs
> are typically of garden variety, not dependent on some
> complex interactions between parallel programs (or worse, on
> processor heisenbugs). You can always try repeating a failing
> test on a more deterministic set up like qemu etc.

Actually, all the bugs I've used stress2 for were race conditions and locking 
bugs for which having a set random seed would not have helped.

> One trick I have used in the past is to record "significant"
> events in one or more ring buffers using some cheap encoding.
> You have then access to past N events during any post kernel
> crash analysis.  This has far less of an overhead than debug
> printfs and you can even leave it enabled in production use.

man ktr

John Baldwin

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