github.com/bhojpur/cache@v0.0.4/pkg/engine/ristretto.go (about)

     1  package engine
     2  
     3  // Copyright (c) 2018 Bhojpur Consulting Private Limited, India. All rights reserved.
     4  
     5  // Permission is hereby granted, free of charge, to any person obtaining a copy
     6  // of this software and associated documentation files (the "Software"), to deal
     7  // in the Software without restriction, including without limitation the rights
     8  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
     9  // copies of the Software, and to permit persons to whom the Software is
    10  // furnished to do so, subject to the following conditions:
    11  
    12  // The above copyright notice and this permission notice shall be included in
    13  // all copies or substantial portions of the Software.
    14  
    15  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    16  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    17  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    18  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    19  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    20  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    21  // THE SOFTWARE.
    22  
    23  import (
    24  	"github.com/bhojpur/cache/pkg/engine/ristretto"
    25  )
    26  
    27  var _ Cache = &ristretto.Cache{}
    28  
    29  // NewRistrettoCache returns a Cache implementation based on Ristretto
    30  func NewRistrettoCache(maxEntries, maxCost int64, cost func(interface{}) int64) *ristretto.Cache {
    31  	// The TinyLFU paper recommends to allocate 10x times the max entries amount as counters
    32  	// for the admission policy; since our caches are small and we're very interested on admission
    33  	// accuracy, we're a bit more greedy than 10x
    34  	const CounterRatio = 12
    35  
    36  	config := ristretto.Config{
    37  		NumCounters: maxEntries * CounterRatio,
    38  		MaxCost:     maxCost,
    39  		BufferItems: 64,
    40  		Metrics:     true,
    41  		Cost:        cost,
    42  	}
    43  	cache, err := ristretto.NewCache(&config)
    44  	if err != nil {
    45  		panic(err)
    46  	}
    47  	return cache
    48  }