Some test code

go.mod

@@ -3,6 +3,6 @@ module git.crumpington.com/public/toolbox
 go 1.16
 
 require (
-	golang.org/x/sys v0.0.0-20201119102817-f84b799fce68 // indirect
+	golang.org/x/sys v0.0.0-20201119102817-f84b799fce68
 	golang.org/x/term v0.0.0-20210317153231-de623e64d2a6
 )

kvmemcache/bench/bench/main.go

@@ -0,0 +1,76 @@
+package main
+
+import (
+	"fmt"
+	"math/rand"
+	"sync"
+	"time"
+
+	"git.crumpington.com/public/toolbox/kvmemcache"
+)
+
+const (
+	mean        = 1000000
+	stdDev      = 100
+	computeTime = 2 * time.Millisecond
+
+	cacheSize = 800
+	cacheTTL  = time.Second
+
+	numThreads = 8
+	numCalls   = 1024 * 1024
+)
+
+func randKey() string {
+	fSample := rand.NormFloat64()*stdDev + mean
+	sample := int64(fSample)
+	return fmt.Sprintf("%d", sample)
+}
+
+func run(c *kvmemcache.Cache, wg *sync.WaitGroup) {
+	defer wg.Done()
+	for i := 0; i < numCalls; i++ {
+		key := randKey()
+		_, _ = c.Get(key)
+	}
+}
+
+func main() {
+	c := kvmemcache.New(kvmemcache.Config{
+		MaxSize: cacheSize,
+		TTL:     cacheTTL,
+		Src: func(key string) (interface{}, error) {
+			time.Sleep(computeTime)
+			return key, nil
+		},
+	})
+
+	wg := &sync.WaitGroup{}
+	wg.Add(numThreads)
+
+	t0 := time.Now()
+
+	for i := 0; i < numThreads; i++ {
+		go run(c, wg)
+	}
+
+	wg.Wait()
+
+	dt := time.Since(t0)
+	dtSec := float64(dt) / float64(time.Second)
+	stats := c.Stats()
+
+	fmt.Printf(`
+Time taken: %12.3f sec
+Hits:       %12d
+Misses:     %12d
+Calls/sec:  %12.3f
+Speedup:    %12.3f
+`,
+		dtSec,
+		stats.Hits,
+		stats.Misses,
+		float64(stats.Hits+stats.Misses)/dtSec,
+		float64(numThreads*numCalls*computeTime)/float64(dt),
+	)
+}

kvmemcache/bench/thunderingherd/main.go

@@ -0,0 +1,45 @@
+package main
+
+import (
+	"log"
+	"sync"
+	"time"
+
+	"git.crumpington.com/public/toolbox/kvmemcache"
+)
+
+func main() {
+	N := 1024 * 2048
+	trigger := make(chan bool)
+
+	c := kvmemcache.New(kvmemcache.Config{
+		MaxSize: 4,
+		Src: func(key string) (interface{}, error) {
+			<-trigger
+			return key, nil
+		},
+	})
+
+	readyGroup := sync.WaitGroup{}
+	doneGroup := sync.WaitGroup{}
+
+	readyGroup.Add(N)
+	doneGroup.Add(N)
+
+	for i := 0; i < N; i++ {
+		go func() {
+			readyGroup.Done()
+			c.Get("a")
+			doneGroup.Done()
+		}()
+	}
+
+	readyGroup.Wait()
+
+	t0 := time.Now()
+	trigger <- true
+	doneGroup.Wait()
+	dt := time.Since(t0)
+
+	log.Printf("%v", dt)
+}