Re: build.sh sets with xz (was Re: vfs cache timing changes)

["Tom Spindler (moof)" <dogcow%babymeat.com@localhost>]

On Fri, Sep 13, 2019 at 06:59:42AM -0400, Greg Troxel wrote:
> (I have not really been building current so am unclear on the xz
> details.)
> 
> I'd like us to keep somewhat separate the notions of:
> 
>   someone is doing build.sh release
> 
>   someone wants min-size sets at the expense of a lot of cpu time

I agree, modulo s/release/sets/, especially when we're doing things
like "reproducible builds" or "make images suitable for giving
others".  Very different use cases. When I'm developing (and/or
trying to verify if the build works), I don't care that the tgz
sets are 1.9x the size of the xz ones [mostly due to comp and base,
if you're curious]; if I'm trying to send them across the net, I do.

The big issue I run into is that `build.sh sets` - which you much
need for most kinds of consistent installation - takes quite a bit
longer and much more CPU with xz as compared to pigz. The results
from doing `build.sh -x sets` in my VM, with the only change being
USE_PIGZGZIP=1 in /etc/mk.conf, are

USE_PIGZGZIP=1 216s user 38s system 80s wallclock
(commented out) 536s user 77s system 279s wallclock

and this is on a relatively modern machine's VM with a fast SSD;
the difference gets greatly amplified on my anemic real-hardware
server boxes.