Re: Rump makes the kernel problematically brittle

[Thor Lancelot Simon <tls%panix.com@localhost>]

On Thu, Apr 02, 2020 at 04:16:35PM -0400, Greg Troxel wrote:
> The other side of the coin to "rump is fragile" is "an operating system
> without rump-style tests that can be run automatically is suscpetible to
> hard-to-detect failures from changes, and is therefore fragile".  There
> have been many instances (usually on current-users, I think) of reports
> of newly-failing tests cases, leading to rapid removal of
> newly-introduced defects.

I have to say I have always found rump a major impediment to kernel
development.  I chalk this up to one problem with rump, and one problem
only, but it is a problem so serious to this day I feel core should not
have allowed rump to be committed to HEAD without it being definitively
resolved.

The problem is that rump duplicates the entire kernel configuration and
build framework -- poorly.  Rump builds more like v7 did than like modern
BSD, and this means that any code added to the kernel typically has to
be fitted into not one build system but two.  This just plain sucks.  It
is shoddy.  It is definitely the case that rump is a huge technical
accomplishment that enables us to do really cool things - with testing,
with userspace network stacks, and more.  But it is tremendously unfortunate
that it was checked into our tree before it was ready, and has remained
that way ever since.

I'd love to see a GSoC project to actually make rump build like the
kernel...but it may be too much work.

Thor

-- 
 Thor Lancelot Simon	                                     tls%panix.com@localhost
  "Whether or not there's hope for change is not the question.  If you
   want to be a free person, you don't stand up for human rights because
   it will work, but because it is right."	--Andrei Sakharov