@artch Is the tombstone spawned with the same id as the original creep, perhaps the code I had to run the creep tried to continue treating it as a creep then? I don't have any code that deals with tombstones. Also, since this error is apparently being thrown from outside my code, I'm not certain how I could catch or remedy it, I resolved it by pushing my code again in the end..

I believe this started happening after a creep died, likely a new creep was scheduled to start spawning. This is running on Shard 1 on the PTR

Error: Could not find an object with ID 5ab24757d06c682273e56812
    at data (:36311:19)
    at Object.get [as spawning] (eval at exports.defineGameObjectProperties (:1121:9), :6:68)
    at Object.exports.defineGameObjectProperties.obj.toJSON (:1140:29)
    at JSON.stringify ()
    at global._init.global._start (:29412:45)
    at ()
    at make (/opt/ivm/engine/dist/core/runtime/make.js:243:31)

I'm also getting this error in PTR, given lookAt(14,24) which is a normal position in the room:

TypeError: Cannot read property '24' of undefined
    at _lookSpatialRegister (:14286:77)
    at Object.lookAt (:14380:9)

This is with IVM enabled

Yes, I'm seeing the same error, withdrawing from a powerSpawn is returning ERR_NOT_ENOUGH_RESOURCES when called with valid parameters currently.

https://github.com/screeps/engine/blob/master/src/game/creeps.js#L627 is the line in error, you can see the correct line below:
https://github.com/screeps/engine/blob/master/src/game/creeps.js#L657

Thanks for pointing me in the direction of Memory.  Initially halving my memory footprint reduced my average usage by about 15CPU/tick, I had no idea that utilizing even 400k would cause such a significant impact on performance.

Currently using about 400k of memory, normal JSON.parse on a private server takes between 8-12CPU/tick from what I have seen.  I get the CPU at the very beginning of the main loop, and check it again immediately after the first load from Memory.  This should be giving me a pretty accurate representation of the parse costs.

What I am seeing though is an extra 15-20CPU scattered randomly throughout the main loop, sometimes in the middle of a creep's behaviour, sometimes lumped in with Memory parsing or other areas.  I can only reasonably assume this is GC, unless you have an alternative explanation.

Understandably getting C code working inside the Screeps environment may not be possible currently, but I would really appreciate some better way of profiling my code.  I have heard that it's possible other player's GC can affect the runtime of our code, is that true?

Hi,

I've been working hard to optimize my code, but I'm struggling with the 6 - 36 CPU that is shaved off of my bucket each tick, supposedly by Garbage Collection(GC).  Random parts of my code (like if statements) start to consume 20CPU in a tick, or if not it shows up at the beginning of the tick.

 I would like to profile my code using something like:

https://github.com/matthieu/node-gc

https://github.com/dainis/node-gcstats

but I'm not certain how I could get these modules to load from within the screeps environment.  Could we have a feature that allows us to better understand how GC is affecting our CPU usage?

Much appreciated.