wehub-resource-sync
96 lines
3.8 KiB
Go
96 lines
3.8 KiB
Go
package prefixcache
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import (
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"fmt"
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"time"
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)
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// Config holds prefix-cache-aware routing settings. Per-model overrides
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// (policy, abs/rel thresholds, min-match) live on ModelSchedulingConfig; TTL
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// and window/depth are global-only.
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type Config struct {
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GlobalPolicy RoutePolicy
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MinPrefixMatch float64 // ratio matched/total, [0,1]
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BalanceAbsThreshold int // absolute in-flight slack
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BalanceRelThreshold float64 // relative load ratio, >= 1
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TTL time.Duration // idle-timeout for entries
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HalfLife time.Duration // recency decay for cacheWeight
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WindowBytes int // chunk window size
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MaxDepth int // max trailing blocks hashed
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// PressureWindow is the rolling window over which forced-disturb events are
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// counted for the autoscale signal (see Pressure). Default 1 minute.
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PressureWindow time.Duration
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// PressureScaleThreshold is the minimum forced-disturb count within
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// PressureWindow that makes the reconciler treat the cache-warm replica as
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// saturated and scale up (subject to MaxReplicas and capacity). Default 1,
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// i.e. any sustained forced-disturb.
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PressureScaleThreshold int
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}
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func DefaultConfig() Config {
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return Config{
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GlobalPolicy: RoutePolicyPrefixCache,
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MinPrefixMatch: 0.3,
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BalanceAbsThreshold: 2,
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BalanceRelThreshold: 1.5,
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TTL: 5 * time.Minute,
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HalfLife: 2 * time.Minute,
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WindowBytes: 256,
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MaxDepth: 64,
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PressureWindow: time.Minute,
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PressureScaleThreshold: 1,
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}
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}
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// validateThresholdBounds enforces the numeric bounds shared between the
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// per-model override validator (ValidateThresholds) and Config.Validate:
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// minMatch in [0,1]; absThr >= 0; relThr == 0 (inherit) or >= 1. It is the
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// single source of truth for those bounds so the endpoint and the global
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// config cannot drift apart.
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func validateThresholdBounds(absThr int, relThr, minMatch float64) error {
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if minMatch < 0 || minMatch > 1 {
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return fmt.Errorf("prefixcache: min_prefix_match must be in [0,1], got %v", minMatch)
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}
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if absThr < 0 {
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return fmt.Errorf("prefixcache: balance_abs_threshold must be >= 0, got %d", absThr)
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}
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if relThr != 0 && relThr < 1 {
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return fmt.Errorf("prefixcache: balance_rel_threshold must be 0 (inherit) or >= 1, got %v", relThr)
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}
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return nil
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}
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// ValidateThresholds checks per-model override bounds. routePolicy must be one
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// of "", "round_robin", "prefix_cache" (explicit allow-list - NOT ParsePolicy,
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// which maps unknown to Default and would accept typos). minMatch in [0,1];
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// absThr >= 0; relThr == 0 (inherit) or >= 1.
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func ValidateThresholds(routePolicy string, absThr int, relThr, minMatch float64) error {
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switch routePolicy {
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case "", "round_robin", "prefix_cache":
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default:
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return fmt.Errorf(`prefixcache: route_policy must be one of "", "round_robin", "prefix_cache", got %q`, routePolicy)
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}
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return validateThresholdBounds(absThr, relThr, minMatch)
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}
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func (c Config) Validate() error {
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// Config.BalanceRelThreshold has no "inherit" sentinel - it is a concrete
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// global value that must be >= 1 - so pass 0 for relThr to the shared
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// numeric check and assert the >= 1 floor here separately.
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if err := validateThresholdBounds(c.BalanceAbsThreshold, 0, c.MinPrefixMatch); err != nil {
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return err
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}
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if c.BalanceRelThreshold < 1 {
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return fmt.Errorf("prefixcache: balance_rel_threshold must be >= 1, got %v", c.BalanceRelThreshold)
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}
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if c.WindowBytes <= 0 || c.MaxDepth <= 0 {
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return fmt.Errorf("prefixcache: window_bytes and max_depth must be > 0")
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}
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// TTL must be positive: it is the entry idle-lifetime and the eviction
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// ticker runs at TTL/2, so time.NewTicker would panic on TTL <= 0.
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if c.TTL <= 0 {
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return fmt.Errorf("prefixcache: ttl must be > 0, got %v", c.TTL)
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}
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return nil
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}
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