"Johannes Kröger (WhereGroup) via Qgis-user" <[email protected]> writes:
> Am 31.07.22 um 18:11 schrieb Mike Stanton via Qgis-user: >> >> It all depends on the module you are running and whether it >> effectively uses the “-multi” option with “all_available_cores” and >> of course how many cores are available on your system. >> > I think there is some confusion here. Greg, can you confirm that you > are talking about QGIS' thread usage "at rest", so when a project is > open and browsed but not while you are running an analysis or data > processing tool? That is how I understand your question. Yes, at rest. I have a project with a lot of layers. Many of them are just gpx files - basically raw data from surveying. I have a bunch of geopackage layers where I store processed observations and my current map data, and then various basemap stuff. I don't do a lot of heavy analysis/processing. It's mostly editing/curating this data and occasional pdf map production. I had this project open on a different desktop after having looked at something (might have opened to ask what is the distance from point x to point y) and just didn't close it. Just idling in display mode. I hadn't touched it in hours. Then I had some other program hit the (wrongly too low, not the point) limit, and on investigation found far more threads than I expected. If I only had N threads, for N = 4 * hw.ncpu, I would not have even thought about writing. But I had 157 on a 4-core machine. > I could imagine that QGIS uses at least one thread per data source. Maybe, but it seems like if it reads a gpx and doesn't intend to reread it that thread should be joined. I opened a very small project, with just an OSM basemap (TMS) and a tiff (from the georeferencer in an earlier session), and had only 16. I added a few geopackage layers and the count bounced around a little and settled at 9. I added a few jp2 tiles and also that settled down. But when I zoomed to a tile, it changed to 16. So it seems .jp2 tiles, when displayed (when in viewport?) provoke thread usage -- but I really mean 'seems' so far.
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