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|
package manager
import (
"context"
"sync"
"sync/atomic"
"testing"
)
func TestMaxSlicePool(t *testing.T) {
pool := newMaxSlicePool(0)
var wg sync.WaitGroup
for i := 0; i < 100; i++ {
wg.Add(1)
go func() {
defer wg.Done()
// increase pool capacity by 2
pool.ModifyCapacity(2)
// remove 2 items
bsOne, err := pool.Get(context.Background())
if err != nil {
t.Errorf("failed to get slice from pool: %v", err)
}
bsTwo, err := pool.Get(context.Background())
if err != nil {
t.Errorf("failed to get slice from pool: %v", err)
}
done := make(chan struct{})
go func() {
defer close(done)
// attempt to remove a 3rd in parallel
bs, err := pool.Get(context.Background())
if err != nil {
t.Errorf("failed to get slice from pool: %v", err)
}
pool.Put(bs)
// attempt to remove a 4th that has been canceled
ctx, cancel := context.WithCancel(context.Background())
cancel()
bs, err = pool.Get(ctx)
if err == nil {
pool.Put(bs)
t.Errorf("expected no slice to be returned")
return
}
}()
pool.Put(bsOne)
<-done
pool.ModifyCapacity(-1)
pool.Put(bsTwo)
pool.ModifyCapacity(-1)
// any excess returns should drop
rando := make([]byte, 0)
pool.Put(&rando)
}()
}
wg.Wait()
if e, a := 0, len(pool.slices); e != a {
t.Errorf("expected %v, got %v", e, a)
}
if e, a := 0, len(pool.allocations); e != a {
t.Errorf("expected %v, got %v", e, a)
}
if e, a := 0, pool.max; e != a {
t.Errorf("expected %v, got %v", e, a)
}
_, err := pool.Get(context.Background())
if err == nil {
t.Errorf("expected error on zero capacity pool")
}
pool.Close()
}
func TestPoolShouldPreferAllocatedSlicesOverNewAllocations(t *testing.T) {
pool := newMaxSlicePool(0)
defer pool.Close()
// Prepare pool: make it so that pool contains 1 allocated slice and 1 allocation permit
pool.ModifyCapacity(2)
initialSlice, err := pool.Get(context.Background())
if err != nil {
t.Errorf("failed to get slice from pool: %v", err)
}
pool.Put(initialSlice)
for i := 0; i < 100; i++ {
newSlice, err := pool.Get(context.Background())
if err != nil {
t.Errorf("failed to get slice from pool: %v", err)
return
}
if newSlice != initialSlice {
t.Errorf("pool allocated a new slice despite it having pre-allocated one")
return
}
pool.Put(newSlice)
}
}
type recordedPartPool struct {
recordedAllocs uint64
recordedGets uint64
recordedOutstanding int64
*maxSlicePool
}
func newRecordedPartPool(sliceSize int64) *recordedPartPool {
sp := newMaxSlicePool(sliceSize)
rp := &recordedPartPool{}
allocator := sp.allocator
sp.allocator = func() *[]byte {
atomic.AddUint64(&rp.recordedAllocs, 1)
return allocator()
}
rp.maxSlicePool = sp
return rp
}
func (r *recordedPartPool) Get(ctx context.Context) (*[]byte, error) {
atomic.AddUint64(&r.recordedGets, 1)
atomic.AddInt64(&r.recordedOutstanding, 1)
return r.maxSlicePool.Get(ctx)
}
func (r *recordedPartPool) Put(b *[]byte) {
atomic.AddInt64(&r.recordedOutstanding, -1)
r.maxSlicePool.Put(b)
}
func swapByteSlicePool(f func(sliceSize int64) byteSlicePool) func() {
orig := newByteSlicePool
newByteSlicePool = f
return func() {
newByteSlicePool = orig
}
}
type syncSlicePool struct {
sync.Pool
sliceSize int64
}
func newSyncSlicePool(sliceSize int64) *syncSlicePool {
p := &syncSlicePool{sliceSize: sliceSize}
p.New = func() interface{} {
bs := make([]byte, p.sliceSize)
return &bs
}
return p
}
func (s *syncSlicePool) Get(ctx context.Context) (*[]byte, error) {
select {
case <-ctx.Done():
return nil, ctx.Err()
default:
return s.Pool.Get().(*[]byte), nil
}
}
func (s *syncSlicePool) Put(bs *[]byte) {
s.Pool.Put(bs)
}
func (s *syncSlicePool) ModifyCapacity(_ int) {
return
}
func (s *syncSlicePool) SliceSize() int64 {
return s.sliceSize
}
func (s *syncSlicePool) Close() {
return
}
|
