What's a "Negative time delta during VM update"

[mikegray]

I'm getting a lot of them in my papyrus logs in game that seems to be running just fine otherwise. (Just fine means: as far as can tell, at this point, for the time being, cross your fingers and knock on wood!)

 

I tend to get longish clumps of them, and they don't seem to connect to any other kind error or warning. They can come right in the middle of, say, Frostfall messages, right before or after a VM freeze or anywhere else. Here's an example of a few lines:

 

[11/23/2013 - 01:08:48PM] warning: Negative time delta during VM update - clamping to 0. (Current: 259419, Previous 259420, Delta: -1)

[11/23/2013 - 01:08:49PM] warning: Negative time delta during VM update - clamping to 0. (Current: 259527, Previous 259528, Delta: -1)

[11/23/2013 - 01:08:49PM] warning: Negative time delta during VM update - clamping to 0. (Current: 259536, Previous 259537, Delta: -1)

I think "VM" means virtual machine, and I'm pretty sure that the message means that for some reason the game is having trouble keeping itself in sync. ("In sync" ... with ... um itself, I guess.)

I'd be perfectly happy to ignore the whole business, but the fact that I can get about 100 lines of this stuff in 4-5 seconds is worrying me a bit!

I've wondered vaguely whether alt-tabbing out of the game could have something to do with this. I have a couple SKSE plugins in that help that work better on my AMD card ... )

Edited November 23, 2013 by mikegray

[Soolie]

The time delta is the Change in time between VM cycles. This is used to keep track of timing and is used in physics calculations. This should never be negative since that would imply that time is running backwards... Which is clearly silly. This is usually a small positive value such as a few milliseconds or something like that. In all of those cases, the time delta is -1. alt-tabbing could indeed be a possible cause of this, Also does it still occur without skse?

[mikegray]

Hmm.

 

This is tricky to gauge - but I DO have a feeling that I get more of them when I'm using all the SKSE plugins to run in windowed mode and switch in and out of Skyrim at will. Repeat: FEELING. Not knowledge, by a long shot!

 

This afternoon, I checked up on my SKSE plugins and discovered that there is a lot of new stuff I haven't been using. (http://skyrim.nexusmods.com/mods/40706/?) I played for more than an hour this afternoon with its various settings on and got very, very nice performance, no CTDs, all good. Did a lot of alt-tabbing. But I also ended up with a 1mb log file, mostly filled with these errors.

 

(Stupidly, I forgot to write down the exact time of each alt-tab.)

 

I'm about to open up the game again with the SKSE stuff turned off and play for maybe 15 minutes without leaving the game. See what happens.

[mikegray]

Hmm.

 

OK, I seem to have found one pattern that holds:

 

As far as I can tell, there is one thing that ALWAYS causes a whole slew of negative delta errors:

 

Opening a different savefile without re-starting the game. I.e., I'm playing with savefile 97, then I go either back or forward to try savefile 93 or 102.

 

Oddly, this is NOT caused by getting killed and having the game automatically re-open the last autosave or the manual save I began playing with.

 

There do seem to be other circumstance that lead to negative delta errors, but, so far, this is the only thing guaranteed to cause them.

Edited November 24, 2013 by mikegray