blob: cfb0ff9dc4f241950ba5875348e48da12590e6bf (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
|
#region Copyright notice and license
// Copyright 2016 gRPC authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#endregion
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Text.RegularExpressions;
using System.Threading;
using System.Threading.Tasks;
using Google.Protobuf;
using Grpc.Core;
using Grpc.Core.Utils;
using Grpc.Testing;
namespace Grpc.IntegrationTesting
{
public interface IInterarrivalTimer
{
void WaitForNext();
Task WaitForNextAsync();
}
/// <summary>
/// Interarrival timer that doesn't wait at all.
/// </summary>
public class ClosedLoopInterarrivalTimer : IInterarrivalTimer
{
public ClosedLoopInterarrivalTimer()
{
}
public void WaitForNext()
{
// NOP
}
public Task WaitForNextAsync()
{
return TaskUtils.CompletedTask;
}
}
/// <summary>
/// Interarrival timer that generates Poisson process load.
/// </summary>
public class PoissonInterarrivalTimer : IInterarrivalTimer
{
readonly ExponentialDistribution exponentialDistribution;
DateTime? lastEventTime;
public PoissonInterarrivalTimer(double offeredLoad)
{
this.exponentialDistribution = new ExponentialDistribution(new Random(), offeredLoad);
this.lastEventTime = DateTime.UtcNow;
}
public void WaitForNext()
{
var waitDuration = GetNextWaitDuration();
int millisTimeout = (int) Math.Round(waitDuration.TotalMilliseconds);
if (millisTimeout > 0)
{
// TODO(jtattermusch): probably only works well for a relatively low interarrival rate
Thread.Sleep(millisTimeout);
}
}
public async Task WaitForNextAsync()
{
var waitDuration = GetNextWaitDuration();
int millisTimeout = (int) Math.Round(waitDuration.TotalMilliseconds);
if (millisTimeout > 0)
{
// TODO(jtattermusch): probably only works well for a relatively low interarrival rate
await Task.Delay(millisTimeout);
}
}
private TimeSpan GetNextWaitDuration()
{
if (!lastEventTime.HasValue)
{
this.lastEventTime = DateTime.Now;
}
var origLastEventTime = this.lastEventTime.Value;
this.lastEventTime = origLastEventTime + TimeSpan.FromSeconds(exponentialDistribution.Next());
return this.lastEventTime.Value - origLastEventTime;
}
/// <summary>
/// Exp generator.
/// </summary>
private class ExponentialDistribution
{
readonly Random random;
readonly double lambda;
readonly double lambdaReciprocal;
public ExponentialDistribution(Random random, double lambda)
{
this.random = random;
this.lambda = lambda;
this.lambdaReciprocal = 1.0 / lambda;
}
public double Next()
{
double uniform = random.NextDouble();
// Use 1.0-uni above to avoid NaN if uni is 0
return lambdaReciprocal * (-Math.Log(1.0 - uniform));
}
}
}
}
|
