Re: 8.0 performance issue when running build.sh?

[Martin Husemann <martin%duskware.de@localhost>]

On Fri, Jul 06, 2018 at 04:04:50PM +0200, Martin Husemann wrote:
> I have no scientific data yet, but just noticed that build times on the
> auto build cluster did rise very dramatically since it has been updated
> to run NetBSD 8.0 RC2.
> 
> Since builds move around build slaves sometimes (not exactly randomly,
> but anyway) I picked the alpha port as an example (the first few
> architectures in the alphabetical list get build slaves assigned pretty
> consistently).

Here is an intermediate result from further experiments and statistics:

 - fpu_eager (as it is on NetBSD 8.0 RC2, which is not what is in -current
   and not what will be in the final 8.0 release) has a measurable performance
   impact - but it is not the big issue here.

 - if we ignore netbsd-7* branches, the performance loss is reasonable 
   explainable by the SVS penalty - we are going to check that theory soon.

 - maybe the netbsd-7 /bin/sh and/or /usr/bin/make cause some very bad
   interaction with SVS, making those build times sky rocket - if turning
   off SVS does not solve this, we will need to dig deeper.

So stay tuned, maybe only Intel to blame ;-)

If anyone has concrete pointers for the last issue (or ideas what to change/
measure) please speak up.

Martin