Improvement - move calls to Game.SaveGameStats into Jobs

[mwerle]

Follow-up to #5927; details in this discussion.

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Web-eWorks:

Something you might consider for a follow-on PR - data/pigui/modules/saveloadgame.lua calls Game.SaveGameStats repeatedly to load details about savefiles on disk. That function should* be able to be moved off-thread using the Job system (finalizing the job and delivering the result via LuaEvent on the main thread) so there isn't a perceptual hitch/stutter when enumerating details about saved games.

That's the equivalent of throwing you in the deep end to see if you can swim, so feel free to demur and I'll tackle it when I get time.

= I've not rigorously analyzed it to ensure it's free of dependencies against the main thread - that would be part of the work involved in moving it to an asynchronous job.

[mwerle]

So I was going to yell for help, but I managed to work it out. Possibly more convolutedly than required..

My draft implementation can be found in #5934

In this implementation, the individual stutters are gone, instead there is one huge long stutter, and the interface updates all at once instead of entry by entry as currently. Perhaps I misunderstood and the Lua Events should be triggered from inside each job, but I have no idea how threadsafe the C++ / Lua interface is..

[mwerle]

...and a very quick test shows that no, it is not threadsafe and blows up.

[syonfox]

Yeah current master branch crashes when I go to the system view.

[syonfox]

Info: Created shader geosphere_terrain (address=0x562de39d9cd0)
Info: Created shader rayleigh_fast (address=0x562de32d44a0)
Fatal: [T] pigui/modules/system-view-ui.lua:419: attempt to call method 'GetSystemSelectionMode' (a nil value)
stack traceback:
[T] pigui/modules/system-view-ui.lua:419: in function 'Show'
[T] pigui/libs/window-layout.lua:85: in function 'fun'
[T] pigui/libs/wrappers.lua:129: in function 'window'
[T] pigui/libs/window-layout.lua:84: in function 'fun'
[T] pigui/libs/wrappers.lua:662: in function 'withFont'
[T] pigui/libs/window-layout.lua:80: in function 'display'
[T] pigui/modules/system-view-ui.lua:909: in function 'fun'
[T] pigui/libs/wrappers.lua:129: in function 'window'
[T] pigui/baseui.lua:52: in function <[T] pigui/baseui.lua:49>

[mwerle]

Yeah current master branch crashes when I go to the system view.

Info: Created shader geosphere_terrain (address=0x562de39d9cd0) Info: Created shader rayleigh_fast (address=0x562de32d44a0) Fatal: [T] pigui/modules/system-view-ui.lua:419: attempt to call method 'GetSystemSelectionMode' (a nil value)

... that's completely unrelated to this work (but the crash does look like it's related to my other PR #5922) ..

I can't repro this crash (master on commit 770ed87 - 20 or so hours ago)

[syonfox]

sorry it seems to work now maybe was a save game bug or something after recompiling it seems to be resolved on a new game.

[mwerle]

sorry it seems to work now maybe was a save game bug or something after recompiling it seems to be resolved on a new game.

No worries; but please do not comment in completely unrelated issues...