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The pool is used mostly for obtaining byte buffers for responses from scrape targets. There are no responses smaller than 256 bytes in practice, so there is no sense in maintaining pools for byte slices up to 64 and 128 bytes.
62 lines
1.3 KiB
Go
62 lines
1.3 KiB
Go
package leveledbytebufferpool
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import (
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"math/bits"
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"sync"
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"github.com/VictoriaMetrics/VictoriaMetrics/lib/bytesutil"
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)
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// pools contains pools for byte slices of various capacities.
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//
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// pools[0] is for capacities from 0 to 256
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// pools[1] is for capacities from 257 to 512
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// pools[2] is for capacities from 513 to 1024
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// ...
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// pools[n] is for capacities from 2^(n+7)+1 to 2^(n+8)
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//
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// Limit the maximum capacity to 2^18, since there are no performance benefits
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// in caching byte slices with bigger capacities.
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var pools [10]sync.Pool
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// Get returns byte buffer, which is able to store at least dataLen bytes.
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func Get(dataLen int) *bytesutil.ByteBuffer {
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id, capacityNeeded := getPoolIDAndCapacity(dataLen)
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for i := 0; i < 2; i++ {
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if id < 0 || id >= len(pools) {
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break
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}
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if v := pools[id].Get(); v != nil {
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return v.(*bytesutil.ByteBuffer)
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}
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id++
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}
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return &bytesutil.ByteBuffer{
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B: make([]byte, 0, capacityNeeded),
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}
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}
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// Put returns bb to the pool.
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func Put(bb *bytesutil.ByteBuffer) {
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capacity := cap(bb.B)
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id, poolCapacity := getPoolIDAndCapacity(capacity)
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if capacity <= poolCapacity {
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bb.Reset()
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pools[id].Put(bb)
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}
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}
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func getPoolIDAndCapacity(size int) (int, int) {
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size--
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if size < 0 {
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size = 0
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}
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size >>= 8
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id := bits.Len(uint(size))
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if id >= len(pools) {
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id = len(pools) - 1
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}
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return id, (1 << (id + 8))
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}
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