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|
package clock //nolint:testpackage
import (
"sync/atomic"
"testing"
)
func benchWeight(_, _ int) uint64 { return 1 }
// goroutineSeq hands each parallel worker a distinct starting offset
// so workers don't go in lockstep over identical keys.
var goroutineSeq atomic.Uint64
func workerOffset() int {
return int(goroutineSeq.Add(1) * 0x9E3779B1)
}
func BenchmarkReadHeavy(b *testing.B) {
// ≈95% Get hits, ≈5% Add, and fits budget.
const n = 100_000
cache := New(n, benchWeight)
for k := range n {
cache.Add(k, k)
}
b.ResetTimer()
b.RunParallel(func(pb *testing.PB) {
i := workerOffset()
for pb.Next() {
i++
key := i % n
if i%20 == 0 {
cache.Add(key, key)
} else {
_, _ = cache.Get(key)
}
}
})
}
func BenchmarkHotKey(b *testing.B) {
// Every worker does Get over a relatively small hot set.
const (
hot = 64
maxWeight = 4096
)
cache := New(maxWeight, benchWeight)
for k := range hot {
cache.Add(k, k)
}
b.ResetTimer()
b.RunParallel(func(pb *testing.PB) {
i := workerOffset()
for pb.Next() {
i++
_, _ = cache.Get(i % hot)
}
})
}
func BenchmarkMixed(b *testing.B) {
// Even split of Get and Add over a working set that fits.
const n = 100_000
cache := New(n, benchWeight)
for k := range n {
cache.Add(k, k)
}
b.ResetTimer()
b.RunParallel(func(pb *testing.PB) {
i := workerOffset()
for pb.Next() {
i++
key := i % n
if i%2 == 0 {
cache.Add(key, key)
} else {
_, _ = cache.Get(key)
}
}
})
}
func BenchmarkChurn(b *testing.B) {
// Every op inserts a fresh key into a small budget.
// I don't think this is likely to happen for git delta caches,
// but this may matter if we use this for other workloads later.
const maxWeight = 4096
cache := New(maxWeight, benchWeight)
b.ResetTimer()
b.RunParallel(func(pb *testing.PB) {
base := workerOffset()
i := 0
for pb.Next() {
i++
cache.Add(base+i, i)
}
})
}
|
