🚀 go-pugleaf

nm...@cus.cam.ac.uk (Nick Maclaren) writes:
> 
> In actual fact, there are bugs that can creep by the 3-level test
> for both compilers and VMs, but they are mind-bogglingly obscure
> by comparison with the ones that adding the third level picks up.
> 

for the resource manager ... I developed an automated benchmarking
system that would generate kernels, auto-reboot, run benchmarks, build
new kernels, run more benchmarks ... and it would run & run & run. The
basic set was 2000 benchmarks that took three months elapsed time to
run (before initial product release).

The benchmarking attempting to choose workloads along the edge of the
"normal" observed operational envelopes, random points withing the
envelope and some number of operations that were way outside any
normal envelope ... say saturating a couple fixed-head paging devices
(hundreds of pages/sec), with huge queues and average service time of
1second.

These outside the envelope benchmarks tended to precipitate zombie
user conditions and numerous timing failures. In order to eliminate
all such cases (from the normal system), I had to totally rewrite the
system serialization primitives in order to eliminate all possible
occurances of zombies & kernel failures because of various asyncronous
timing problems.

random refs:
http://www.garlic.com/~lynn/94.html#52
http://www.garlic.com/~lynn/2001c.html#13
http://www.garlic.com/~lynn/2001e.html#45
http://www.garlic.com/~lynn/2001f.html#56
http://www.garlic.com/~lynn/subtopic.html#fairshare

and of course, my favorite "envelope" subject:
http://www.garlic.com/~lynn/subtopic.html#boyd

-- 
Anne & Lynn Wheeler   | ly...@garlic.com -  http://www.garlic.com/~lynn/