[0.17.23] UPS drop when map overlay toggled

[Areckahn]

The game suffers UPS drops for several seconds when pressing any of the the map overlay options. It dos not seem to matter whether the option is being enabled or disabled, simply changing the state casues UPS to fall drastically if it was previously in a steady state.

In the attached save, when played in multiplayer, the UPS reliably (not every time, but almost all) dropped to 30 for several seconds when the host (but not the other player) toggled any of the map overlay options.

Loading the same game in single player caused similar issues, but the UPS loss was less severe, tending to only drop to the mid 40s or high 50s.

The game generally runs at a stable UPS of 60 when not toggling map options, though there are occaisional drops for unknown reasons, and sometimes following autosaves.

Save game, log, and debug screenshot taken during a UPS drop are attached.

[Rseding91]

Thanks for the report. All of the time is spent flipping the rendered image onto the screen (calling flip). Most likely because it's waiting on vsync and in combination with your 4k resolution it's just too much for it to render each frame.

You can probably disable vsync to work around the slowdown.

[posila]

in combination with your 4k resolution it's just too much for it to render each frame.

I wouldn't blame it on 4K ... GTX 1080 should handle Factorio in 4K without any problem; it even shows draw engine GPU time is just 2ms.

I am interested to know if the problem persists if you disable "Wait for V-Sync" in graphics options, though. Also, would your screen happen to have G-sync?

[Areckahn]

Issue certainly seems related to vsync setting.

Log for a session which includes playing about with the vsync setting is attached.

The no "no_vsync" screenshot does also show some ups drop, but it took about 5 seconds of spam clicking the pollution toggle to get it, and it recovered almost instantly (as opposed to when vysnc is enabled which causes more severe longer lasting ups drop).

Probably worth mentioning that with vsync enabled FPS locks at 30 (which I'm pretty sure it didn't pre v0.17 but I don't have any actual evidence of that to hand), but with vysnc disabled I get some pretty horrible tearing artifacts. I've been meaning to raise these as a separate issue but hadn't got round to it yet

AFAIK monitor is not g-sync (this model)

[Areckahn]

Also, enabling vsync is a nice reliable way for to be cause a huge ups drop for several seconds without the map being involved at all.