GC-notes.txt

REFERENCE COUNTING (NOT USED IN .NET)
Pros:
- Deterministic
- Incremental work
- simple implementation
Cons:
- Mutator's overhead - best case is within 10% of the fastest tracing GC
- Cyclic references
may use deferred reference counting

TRACING
Pros:
- Simple to use
- "Faster" - smaller mutator overhead with only occasional pauses
- Handles cyclic references out of the box
Cons:
- Non-deterministic deallocation
- Not always pauseless
- Can be hard to implement

In .NET we have various runtimes but only a few GC implementations.
The GC has two modes of operation: workstation and server.
The workstation GC is the default on client machines and the server GC is the default on server machines.
The server GC is optimized for throughput, while the workstation GC is optimized for latency.
The GC has three generations: 0, 1, and 2.


The GC is a generational, mark-and-sweep, compacting, stop-the-world, tracing GC. 
It is a conservative GC, meaning that it will not move objects that are not known to be references.
It is a compacting GC, meaning that it will move objects around in memory to reduce fragmentation. 
It is a generational GC, meaning that it will treat objects differently based on their age. 
It is a mark-and-sweep GC, meaning that it will mark objects that are still in use and sweep away those that are not.
It is a stop-the-world GC, meaning that it will pause all threads while it does its work.
It is a tracing GC, meaning that it will follow references to find all live objects.