Update metrics tracking and enhance cache eviction strategies

- Added metrics for bytes saved from cache to improve performance insights.
- Updated cache eviction strategies in MemoryFS and DiskFS to include metrics tracking for hits and evictions.
- Enhanced README.md with updated garbage collection algorithm descriptions and recommendations for cache usage.
- Introduced new madviseSequential functionality for improved memory access hints on Unix systems.
- Adjusted validation configuration in examples to better reflect realistic usage scenarios.

README.md

@@ -261,11 +261,11 @@ SteamCache2 supports different garbage collection algorithms for memory and disk
 **Available GC Algorithms:**
 
 - **`lru`** (default): Least Recently Used - evicts oldest accessed files
-- **`lfu`**: Least Frequently Used (P1 real impl) - evicts by lowest AccessCount (tiebreak older ATime); uses existing FileInfo counters
-- **`fifo`**: First In, First Out - evicts oldest created files (predictable)
-- **`largest`**: Size-based - evicts largest files first (maximizes file count)
-- **`smallest`**: Size-based - evicts smallest files first (maximizes cache hit rate)
-- **`hybrid`**: Recency + frequency hybrid (P1 meaningful) - evicts by lowest time-decayed score (GetTimeDecayedScore combining ATime + AccessCount)
+- **`lfu`**: Least Frequently Used - evicts by lowest AccessCount (tiebreak older ATime); uses existing FileInfo counters
+- **`fifo`**: First In, First Out - evicts oldest created files (predictable and terrible all in one) don't ever use it
+- **`largest`**: Size-based - evicts largest files first (maximizes small file count) if used on memory greatly improves access time
+- **`smallest`**: Size-based - evicts smallest files first (maximizes large file count) probably best used for disk since there kinda slow with small files
+- **`hybrid`**: Recency + frequency hybrid - evicts by lowest time-decayed score (GetTimeDecayedScore combining ATime + AccessCount)
 
 **Recommended Algorithms by Cache Type:**
 
@@ -273,18 +273,19 @@ SteamCache2 supports different garbage collection algorithms for memory and disk
 - **`lru`** - Best overall performance, good balance of speed and hit rate
 - **`lfu`** - Excellent for gaming cafes where popular games stay cached
 - **`hybrid`** - Optimal for mixed workloads with varying file sizes
+- **`largest`** - Crazy good for access times since disks are slow with lots of tiny files
 
 **For Disk Cache (Slow, Large Size):**
 - **`hybrid`** - Recommended for optimal performance, balances speed and storage efficiency
-- **`largest`** - Good for maximizing number of cached files
+- **`smallest`** - Good for maximizing linear reads which is the only place spinning disks have performance don't expect too much though steam kinda uses small files
 - **`lru`** - Reliable default with good performance
 
 **Use Cases:**
-- **Gaming Cafes**: Use `lfu` for memory, `hybrid` for disk
-- **LAN Events**: Use `lfu` for memory, `hybrid` for disk
-- **Home Use**: Use `lru` for memory, `hybrid` for disk
-- **Testing**: Use `fifo` for predictable behavior
-- **Large File Storage**: Use `largest` for disk to maximize file count
+- **Gaming Cafes**: Use `largest` for memory, `hybrid` for disk
+- **LAN Events**: Use `largest` for memory, `hybrid` for disk
+- **Home Use**: Use `largest` for memory, `hybrid` for disk
+- **Testing**: Use `fifo` for nothing its pointless
+- **Large File Storage**: Use `smallest` for disk get rid of the slow tiny files first
 
 ### DNS Configuration