github.com/cloudwego/kitex@v0.9.0/pkg/loadbalance/iterator.go (about)

     1  /*
     2   * Copyright 2023 CloudWeGo Authors
     3   *
     4   * Licensed under the Apache License, Version 2.0 (the "License");
     5   * you may not use this file except in compliance with the License.
     6   * You may obtain a copy of the License at
     7   *
     8   *     http://www.apache.org/licenses/LICENSE-2.0
     9   *
    10   * Unless required by applicable law or agreed to in writing, software
    11   * distributed under the License is distributed on an "AS IS" BASIS,
    12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13   * See the License for the specific language governing permissions and
    14   * limitations under the License.
    15   */
    16  
    17  package loadbalance
    18  
    19  import (
    20  	"sync/atomic"
    21  
    22  	"github.com/bytedance/gopkg/lang/fastrand"
    23  )
    24  
    25  // round implement a strict Round Robin algorithm
    26  type round struct {
    27  	state uint64    // 8 bytes
    28  	_     [7]uint64 // + 7 * 8 bytes
    29  	// = 64 bytes
    30  }
    31  
    32  func (r *round) Next() uint64 {
    33  	return atomic.AddUint64(&r.state, 1)
    34  }
    35  
    36  func newRound() *round {
    37  	r := &round{}
    38  	return r
    39  }
    40  
    41  func newRandomRound() *round {
    42  	r := &round{
    43  		state: fastrand.Uint64(),
    44  	}
    45  	return r
    46  }