Evaluating SystemTap for Network Response Times

[Frank Ch. Eigler]

Nathan DeBardeleben <ndebard@lanl.gov> writes:

> [...]  We probably wouldn't be willing to do anymore static kernel
> instrumentation.  [...]

Understood.

> [...]  Believe it or not - we find kernel bugs semi-regularly, and
> they can waste tons of our time trying to track them down. [...]

Actually, it's not hard to believe.  Back when I worked on a system
that was a heavy user of the kernel (a big database server), one of
its architects mentioned that of all the bugs they found, roughly 25%
were in the OS kernel.  I asked what fraction of time was spent in the
kernel, and it also happened to be around 25%.  We both then realized
that this might not be a coincidence.

- FChE