Re: Retiring WITHOUT_CXX

From: Warner Losh <>
Date: Fri, 26 Nov 2021 18:48:44 UTC
On Fri, Nov 26, 2021 at 11:26 AM Rodney W. Grimes <> wrote:

> > --------
> > Baptiste Daroussin writes: > On Fri, Nov 26, 2021 at 09:09:54AM -0800,
> Rodney W. Grimes wrote:
> >
> > > > You can disagree with my assertion, but I shall continue to assert
> > > > that it *seems* as if rather than adding B O S to the CI
> >
> > I dont know how long time B-O-S runs these days, it used to take
> > a couple of weeks, and I have a hard time squaring that with any
> > contemporary use of the "CI" paradigme :-)
> Dexter can provide an exact number, but IIRC on his purpose built
> test box it is on the order of 2 or 3 days.

I can do a clean buildworld in about ~20-30 minutes on my fastest machine.
There's ~300 build options which puts us at ~74 hours, or ~3 days. I've
not done a build survey, though, to know for sure. Note that this doesn't do
combinations, which is a combinatoric explosion in size (even doing all
would be 150x slower).

Which is at least ~20x too slow to put into any pre-commit workflow, but
would be suitable for periodic testing, perhaps. But then we need to ask if
that ~75 hours of CPU time on a 128-thread CPU generates useful information
in proportion to the size of the test...

But it boils down to all things having a cost. And some costs are too great.