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37 lines
700 B
Go
37 lines
700 B
Go
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// Copyright (c) Tailscale Inc & AUTHORS
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// SPDX-License-Identifier: BSD-3-Clause
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//go:build !tailscale_go
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package syncs
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import (
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"runtime"
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"sync"
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"sync/atomic"
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)
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type shardValuePool struct {
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atomic.Int64
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sync.Pool
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}
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// NewShardValue constructs a new ShardValue[T] with a shard per CPU.
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func NewShardValue[T any]() *ShardValue[T] {
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sp := &ShardValue[T]{
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shards: make([]T, runtime.NumCPU()),
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}
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sp.pool.New = func() any {
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i := sp.pool.Add(1) - 1
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return &sp.shards[i%int64(len(sp.shards))]
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}
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return sp
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}
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// One yields a pointer to a single shard value with best-effort P-locality.
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func (sp *ShardValue[T]) One(yield func(*T)) {
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v := sp.pool.Get().(*T)
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yield(v)
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sp.pool.Put(v)
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}
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