## Summary
- **Timer-aware idle sleep**: Exposes `Timer.MillisecondsUntilNextTick()` to calculate remaining ms until the next timer wheel tick (0–8ms). The game loop sleeps for that duration minus a 1ms safety margin, instead of spinning at 100% CPU.
- **I/O completion wakeup**: Replaces `Thread.Sleep` with `NetState.WaitForCompletion()`, which uses platform-native completion notification (RIO `RIONotify` on Windows, `eventfd` on Linux, `kevent` timeout on macOS) to wake immediately when network data arrives during sleep.
- **Always-on**: Removes the debug-only `core.enableIdleCPU` config gate. The sleep is self-regulating — under load, `MillisecondsUntilNextTick` returns 0 so no sleep occurs (zero overhead). On idle, CPU drops from ~100% to ~1%.
- **CPS calculation cleanup**: Replaces the 128-element ring buffer with an EMA (exponential moving average) for `CyclesPerSecond`/`AverageCPS` — fewer allocations, no LINQ `.Average()` call each sample.
- **IORingGroup 1.0.6**: Adds `WaitForCompletion(int timeoutMs)` to the `IIORingGroup` interface with platform implementations:
- **Windows**: `RIONotify` arms the CQ event, `WaitForSingleObject` with timeout
- **Linux**: `eventfd` registered with io_uring, `poll()` with timeout
- **macOS**: `kevent()` with timeout
## Test plan
- [ ] Build succeeds on all platforms (`dotnet build`)
- [ ] Empty server: verify CPU usage drops from ~100% to ~1% idle
- [ ] Loaded server: verify no added latency — `MillisecondsUntilNextTick` returns 0 when timers are firing, sleep is skipped
- [ ] Connect a client during idle — verify connection accepted within one timer tick (~8ms)
- [ ] Verify `[admin` gump shows reasonable CPS values (EMA convergence)
### Summary
Fixes a few minor issues with timers:
- Timer.Delay and Timer.Interval was not reflecting the actual tick time (aligned to the next 8ms)
- Negative delay values were causing a crash when DateTime.Now - delay was below DateTime.MinValue
- Timer.Next now reflects the correct wall clock tick time based on the adjusted Delay.
- Timer.Next is not assigned when the timer is started. This was important for timers that were created, but started later.
### Summary
- Fixes timer intervals not continuing
- Fixes `Timer.Index` being off by 1. Should start at 0 for the first OnTick
- Simplifies Gift of Renewal end check
- Fixes force of nature not applying at the proper time and simplifies the timer logic.
* Fixes an edge case where a check to see if a timer was being executed resulted in it not being properly detached on stop. Fixed this by changing how we determine what timer is currently being executed.
* Adds execution count to #DEBUG_TIMERS so shards can get notified (rudimentarily for now) about sequentially executing long chains of timers.
Unfortunately, for now, there is no good option when it comes to executing timers. If we execute let's say 500, and defer the rest, that makes all timers effectively 8ms off until it "catches up". Depending on the shard, that may never happen.
**Only one functional change**
* Fixes a bug in LogFactory where `Warning` is being logged as `Information`
Non-functional changes:
* Updates/Fixes copyright headers
* Removes namespace scopes for core files.
View with [whitespace off](https://github.com/modernuo/ModernUO/pull/1187/files?w=1).
* Makes EnsureDirectory properly work for relative and absolute paths
* Adds a `PathUtility.GetFullPath` which returns full paths for relative paths to `Core.BaseDirectory`. If the path is absolute, it will return as-is.
* Moves EnsureDirectory to `PathUtility`. So `ScriptsHandler.EnsureDirectory` and `AssemblyHandler.EnsureDirectory` are now `PathUtility.EnsureDirectory`
* Fixes crash guard so that it copies accounts properly.
* Changes world save and auto archive to use a random folder name inside of the temp folder.
1. Stopping a different timer, on the same slot as the timer being executed during OnTick
* Adds a check for the timer wheel currently being executed and does not detach the timer on Stop().
1. Timers are added to the current slot if they need 4095 slots, before the chain is fully detached/executed
* Removes all chains that will be executed from the timer wheel before executing.
* Fixed an issue where a timer truncated the link list.
* Fixed an issue where a timer stopped and started itself within an OnTick causing it to remove itself from the link list, but still think it's running.
* Fixes pooled timer leaking
* Fixes `[dumptimers` command so it outputs properly, adds spacing, and stacktraces
* Adds `[Tidy]` for serializing Lists. This will remove deleted entities during world save before serializing the list.
* Adds helpers for managing Lists/Sets/Dictionaries
### New API
```cs
// Creates the list if it is null, then adds
Utility.Add(ref list, value);
Utility.Add(ref set, value);
Utility.Add(ref dict, key, value);
// Nulls the variable if the count is zero
Utility.Remove(ref list, value);
Utility.Remove(ref set, value);
Utility.Remove(ref dict, key);
// Marks entity as dirty in addition to doing the action
entity.Add(list, value);
// Marks entity as dirty, and will create list if it doesn't exist
entity.Add(ref list, value);
// Marks entity as dirty in addition to doing the action
entity.Remove(list, value);
// Marks entity as dirty, and will null the list count is zero
entity.Remove(ref list, value);
```
### Updates to [dumptimers
<img width="825" alt="Screen Shot 2021-08-14 at 2 55 10 AM" src="https://user-images.githubusercontent.com/3953314/129442449-ccf7fe14-29d6-4f3f-9366-c8eb7b9828a7.png">
### Changes/Fixes:
* Adds timer pooling.
* Allows pool to be configurable in ModernUO.json
* Pool replenishes itself asynchronously if depleted.
* Fixes an issue with barkeeps and town criers
* Fixes an issue with incognito buff icons not being removed
* Fixes an issue with polymorph name mod not being removed
* Fixes several places where timers go on forever even after an object is deleted, keeping a reference (memory leak)
* Eliminates the timer for MiningCart altogether.
* Deletes `AcidSlime` since it is a duplicate of `PoolOfAcid`
* Fixes HonorableExecution and standardizes the code for other Bushido moves.
## Changes to the Timer API:
```cs
public class Timer
{
// Creates a timer that will be returned to the pool once execution stops.
public static void StartTimer(Action callback);
public static void StartTimer(TimeSpan delay, Action callback);
public static void StartTimer(TimeSpan delay, TimeSpan interval, Action callback);
public static void StartTimer(TimeSpan interval, int count, Action callback);
public static void StartTimer(TimeSpan delay, TimeSpan interval, int count, Action callback);
// Creates a timer and returns a token for more control. Requires manual cancellation in order for the timer to be returned to the pool.
// If the token is dereferenced, the timer will be dereferenced too. While not returning a timer to the pool is not considered hazardous, it does defeat the purpose of pooled timers.
public static void StartTimer(Action callback, out TimerExecutionToken token);
public static void StartTimer(TimeSpan delay, Action callback, out TimerExecutionToken token);
public static void StartTimer(TimeSpan delay, TimeSpan interval, Action callback, out TimerExecutionToken token);
public static void StartTimer(TimeSpan interval, int count, Action callback, out TimerExecutionToken token);
public static void StartTimer(TimeSpan delay, TimeSpan interval, int count, Action callback, out TimerExecutionToken token);
// If you aren't sure how to use the API above, or you don't care about performance, then you can use the old RunUO Timer.DelayCall
public static DelayCallTimer DelayCall(Action callback);
public static DelayCallTimer DelayCall(TimeSpan delay, Action callback);
public static DelayCallTimer DelayCall(TimeSpan delay, TimeSpan interval, Action callback);
public static DelayCallTimer DelayCall(TimeSpan interval, int count, Action callback);
public static DelayCallTimer DelayCall(TimeSpan delay, TimeSpan interval, int count, Action callback);
}
public struct TimerExecutionToken
{
public bool Running { get; }
public int Index { get; }
public int RemainingCount { get; }
public DateTime Next { get; }
}
```
## When to use `TimerExecutionToken`?
Use tokens when you want to gain the performance benefit of using a pooled timer, but you need one of the following:
* Access to the next time the timer will tick:`token.Next`
* Access to which interval, how many intervals there are, or how many are remaining: `token.Index`, `token.Count`, and `token.RemainingCount`
* Stop a timer manually.
* Determine if the timer is running: `timer.Running`
* See notes below about requirements for using tokens!
## Notes about using the TimerExecutionToken:
When you opt-in to receive a token, you must call `Cancel()` to return the timer. This can be done inside of the callback, or outside of the callback at any time.
If this is not called and your timer is an infinite interval, then you will create a potential memory leak, or null pointer exception in your callback.
If the timer ends and is stopped, but cancel is not called, then the timer will never return to the pool and stay referenced until the token is deleted or cancel is called. (Memory leak)
## Is this thread safe?
No. The ModernUO timer system is not thread safe at all. If you require a thread safe timer system, contact me and I'll help adapt this system. Keep in mind that there is a massive performance hit to make this thread safe when there are literally no use cases for it.
If you need to synchronize execution, meaning you want to execute code from another thread on the core thread. Let's say you have a discord bot that is pushing commands to the game server. Then use `EventLoopContext.Post(SendOrPostCallback callback, object state);`.
