[Qgis-user] excessive threads?

[Greg Troxel]

(I realize excessive is relative.  Back when I was young, we didn't have
any threads at all....)

My desktop is NetBSD 9, I ran out of threads, and found that qgis 3.22.8
was using 157 threads, much more than I expected.

Yes, I know 157 is not a super large number, and that the limit of 1024
threads is not tuned for hardware that's good enough to really use qgis.
(For various reasons, partially historical inertia, partially because
most NetBSD people have a computing history that tends towards what
today might be called minimalism, and because NetBSD is used on old
hardware and hardware with very little memory (if it doesn't run in 128
MB we think that's a bug), some of the default limits are too low.
Obviously when doing big things those limits need to be increased, but
it tends to surface resource usage that's higher than perhaps it should
be.  This is aligned with the idea that developers should have to use
the programs they are developing on at laest 10 year old normal hardware
to see what it's like.)

My qgis instance has a lot of layers, but many are geopackage, many are
shapefiles, a couple are postgis, a few are online TMS, a few are TIF,
and a few are jp2 tiles.  While it takes 20s to start up (machine is
2014 4-core, 24G RAM, 2T SSD), it's fast once started.

I really don't understand:

  What is qgis using threads for?

  Do others see large (100 or so, vs 10) thread counts?

  Why are there 157 (really, why are there more than about 10-20)?

Thanks,
Greg
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