Struct SlruCacheMetrics

pub struct SlruCacheMetrics {
    pub core: CoreCacheMetrics,
    pub probationary_size: u64,
    pub protected_size: u64,
    pub protected_max_size: u64,
    pub total_promotions: u64,
    pub total_demotions: u64,
    pub probationary_hits: u64,
    pub protected_hits: u64,
    pub probationary_evictions: u64,
    pub protected_evictions: u64,
}

SLRU-specific metrics (extends CoreCacheMetrics)

This struct contains metrics specific to the SLRU (Segmented LRU) cache algorithm. SLRU divides the cache into probationary and protected segments, so these metrics focus on segment utilization and promotion/demotion patterns.

Fields

core: CoreCacheMetrics

Core metrics common to all cache algorithms

probationary_size: u64

Number of items currently in the probationary segment

protected_size: u64

Number of items currently in the protected segment

protected_max_size: u64

Maximum allowed size for the protected segment

total_promotions: u64

Total number of promotions from probationary to protected segment

total_demotions: u64

Total number of demotions from protected to probationary segment

probationary_hits: u64

Number of cache hits in the probationary segment

protected_hits: u64

Number of cache hits in the protected segment

probationary_evictions: u64

Number of evictions from the probationary segment

protected_evictions: u64

Number of evictions from the protected segment

Implementations

impl SlruCacheMetrics

pub fn new(max_cache_size_bytes: u64, protected_max_size: u64) -> Self

Creates a new SlruCacheMetrics instance with the specified parameters

Arguments

• max_cache_size_bytes - The maximum allowed cache size in bytes
• protected_max_size - The maximum number of items in protected segment

pub fn record_promotion(&mut self)

Records a promotion from probationary to protected segment

pub fn record_demotion(&mut self)

Records a demotion from protected to probationary segment

pub fn record_probationary_hit(&mut self, object_size: u64)

Records a cache hit in the probationary segment

Arguments

• object_size - Size of the object that was served from cache (in bytes)

pub fn record_protected_hit(&mut self, object_size: u64)

Records a cache hit in the protected segment

Arguments

• object_size - Size of the object that was served from cache (in bytes)

pub fn record_probationary_eviction(&mut self, evicted_size: u64)

Records an eviction from the probationary segment

Arguments

• evicted_size - Size of the evicted object (in bytes)

pub fn record_protected_eviction(&mut self, evicted_size: u64)

Records an eviction from the protected segment

Arguments

• evicted_size - Size of the evicted object (in bytes)

pub fn update_segment_sizes( &mut self, probationary_size: u64, protected_size: u64, )

Updates the segment sizes

Arguments

• probationary_size - Current number of items in probationary segment
• protected_size - Current number of items in protected segment

pub fn protection_ratio(&self) -> f64

Calculates the protection ratio (protected hits / total hits)

Returns

Ratio of hits in protected segment vs total hits, or 0.0 if no hits

pub fn promotion_efficiency(&self) -> f64

Calculates the promotion efficiency (promotions / probationary hits)

Returns

How often probationary hits lead to promotions, or 0.0 if no probationary hits

pub fn protected_utilization(&self) -> f64

Calculates protected segment utilization

Returns

Ratio of current protected size to maximum protected size

pub fn to_btreemap(&self) -> BTreeMap<String, f64>

Converts SLRU metrics to a BTreeMap for reporting

This method returns all metrics relevant to the SLRU cache algorithm, including both core metrics and SLRU-specific segment metrics.

Uses BTreeMap to ensure consistent, deterministic ordering of metrics.

Returns

A BTreeMap containing all SLRU cache metrics as key-value pairs

Trait Implementations

impl CacheMetrics for SlruCacheMetrics

fn metrics(&self) -> BTreeMap<String, f64>

Returns all SLRU cache metrics as key-value pairs in deterministic order

Returns

A BTreeMap containing all metrics tracked by this SLRU cache instance

fn algorithm_name(&self) -> &'static str

Returns the algorithm name for this cache implementation

Returns

“SLRU” - identifying this as a Segmented Least Recently Used cache

impl Clone for SlruCacheMetrics

fn clone(&self) -> SlruCacheMetrics

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for SlruCacheMetrics

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.