Struct MetricsCache 

pub struct MetricsCache {
    pub cpu: CpuMetricsCache,
    pub memory: MemoryMetricsCache,
    pub process: ProcessMetricsCache,
    pub network: NetworkMetricsCache,
    pub gpu: GpuMetricsCache,
    pub frame_id: u64,
    pub updated_at_us: u64,
}

Cached metrics snapshot for O(1) panel access.

This struct provides pre-computed, cached views of system metrics to avoid redundant calculations during rendering. Per the spec: “All metrics must be O(1) cached views, not O(n) per-frame refreshes.”

Architecture

┌─────────────────────────────────────────────────────────────────┐
│  collect_metrics() [O(n)]  →  MetricsCache  →  render() [O(1)]  │
│                                                                  │
│  ┌─────────────┐     ┌─────────────┐     ┌─────────────────┐    │
│  │ /proc scan  │ →   │ SIMD Reduce │ →   │ Cached Summary  │    │
│  │ (2600 PIDs) │     │ (AVX2/NEON) │     │ (top 50, sums)  │    │
│  └─────────────┘     └─────────────┘     └─────────────────┘    │
└─────────────────────────────────────────────────────────────────┘

Performance Targets

Operation	Target	Notes
Cache update	<100ms	Once per collect_metrics()
Cache read	<1μs	O(1) field access
Memory overhead	<1KB	Just aggregates, not full data

Fields

cpu: CpuMetricsCache

Cached CPU aggregate

memory: MemoryMetricsCache

Cached memory aggregate

process: ProcessMetricsCache

Cached process aggregate

network: NetworkMetricsCache

Cached network aggregate

gpu: GpuMetricsCache

Cached GPU aggregate

frame_id: u64

Frame ID when cache was last updated

updated_at_us: u64

Timestamp of last update (for cache invalidation)

Implementations

impl MetricsCache

pub fn new() -> Self

Create a new empty cache

pub fn is_stale(&self, current_time_us: u64, max_age_us: u64) -> bool

Check if cache is stale (older than max_age_us)

pub fn update_cpu( &mut self, per_core: &[f64], load_avg: [f32; 3], freq_ghz: f32, frame_id: u64, )

Update CPU cache from raw data

pub fn update_memory( &mut self, used: u64, total: u64, cached: u64, swap_used: u64, swap_total: u64, zram_ratio: f32, )

Update memory cache from raw data

pub fn update_process( &mut self, total: u32, running: u32, sleeping: u32, top_cpu: Option<(u32, f32, String)>, top_mem: Option<(u32, f32, String)>, total_cpu: f32, )

Update process cache from raw data

pub fn update_network( &mut self, interface: String, rx_rate: u64, tx_rate: u64, total_rx: u64, total_tx: u64, conn_count: u32, )

Update network cache from raw data

pub fn update_gpu( &mut self, name: String, usage: f32, vram: f32, temp: f32, power: f32, )

Update GPU cache from raw data

pub fn mark_updated(&mut self, timestamp_us: u64)

Set timestamp for cache freshness tracking

Trait Implementations

impl Clone for MetricsCache

fn clone(&self) -> MetricsCache

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for MetricsCache

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

Formats the value using the given formatter.

impl Default for MetricsCache

fn default() -> MetricsCache

Returns the “default value” for a type.