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
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
|
// -*- C++ -*-
//=============================================================================
/**
* @file LB_LoadMinimum.h
*
* $Id$
*
* @author Jaiganesh Balasubramanian <jai@dre.vanderbilt.edu>
* Ossama Othman <ossama@uci.edu>
*/
//=============================================================================
#ifndef LB_LOAD_MINIMUM_H
#define LB_LOAD_MINIMUM_H
#include /**/ "ace/pre.h"
#include "LB_LoadMap.h"
# if !defined (ACE_LACKS_PRAGMA_ONCE)
# pragma once
# endif /* ACE_LACKS_PRAGMA_ONCE */
#include "orbsvcs/orbsvcs/CosLoadBalancingS.h"
#include "ace/Synch_Traits.h"
#include "ace/Thread_Mutex.h"
namespace TAO_LB
{
/**
* @name Default LoadMinimum strategy parameters.
*
* Defaults defined by the Load Balancing specification.
*/
//@{
const CORBA::Float LM_DEFAULT_TOLERANCE = 1;
const CORBA::Float LM_DEFAULT_DAMPENING = 0;
const CORBA::Float LM_DEFAULT_PER_BALANCE_LOAD = 0;
//@}
/**
* @name TAO-specific LoadMinimum strategy parameters.
*
* Parameters internal to TAO's LoadMinimum strategy
* implementation.
*/
//@{
/// Percentage difference between two load values that determines
/// whether the loads are considered equivalent.
/**
* If the percent difference between two loads, i.e.:
* (Old Load - New Load) / New Load
* is less than or equal to this value, the two loads will be
* considered equivalent. In such a case, an object group member
* residing at the location corresponding to one of the two loads
* will be selected at random.
*/
const CORBA::Float LM_DEFAULT_LOAD_PERCENT_DIFF_CUTOFF = 0.05f; // 1%
const CORBA::Float LM_DEFAULT_DIFF_AVERAGE_CUTOFF = 0.4f; // 80%
//@}
}
/**
* @class TAO_LB_LoadMinimum
*
* @brief "Least loaded" load balancing strategy
*
* This load balancing strategy is designed to select an object group
* member residing at a location with the smallest load.
*/
class TAO_LB_LoadMinimum
: public virtual POA_CosLoadBalancing::Strategy,
public virtual PortableServer::RefCountServantBase
{
public:
/// Constructor.
TAO_LB_LoadMinimum (PortableServer::POA_ptr poa);
/**
* @name CosLoadBalancing::Strategy methods
*
* Methods required by the CosLoadBalancing::Strategy interface.
*/
//@{
virtual char * name (ACE_ENV_SINGLE_ARG_DECL_WITH_DEFAULTS)
ACE_THROW_SPEC ((CORBA::SystemException));
virtual CosLoadBalancing::Properties * get_properties (
ACE_ENV_SINGLE_ARG_DECL_WITH_DEFAULTS)
ACE_THROW_SPEC ((CORBA::SystemException));
virtual void push_loads (
const PortableGroup::Location & the_location,
const CosLoadBalancing::LoadList & loads
ACE_ENV_ARG_DECL_WITH_DEFAULTS)
ACE_THROW_SPEC ((CORBA::SystemException));
virtual CosLoadBalancing::LoadList * get_loads (
CosLoadBalancing::LoadManager_ptr load_manager,
const PortableGroup::Location & the_location
ACE_ENV_ARG_DECL_WITH_DEFAULTS)
ACE_THROW_SPEC ((CORBA::SystemException,
CosLoadBalancing::LocationNotFound));
virtual CORBA::Object_ptr next_member (
PortableGroup::ObjectGroup_ptr object_group,
CosLoadBalancing::LoadManager_ptr load_manager
ACE_ENV_ARG_DECL_WITH_DEFAULTS)
ACE_THROW_SPEC ((CORBA::SystemException,
PortableGroup::ObjectGroupNotFound,
PortableGroup::MemberNotFound));
virtual void analyze_loads (
PortableGroup::ObjectGroup_ptr object_group,
CosLoadBalancing::LoadManager_ptr load_manager
ACE_ENV_ARG_DECL_WITH_DEFAULTS)
ACE_THROW_SPEC ((CORBA::SystemException));
//@}
/// Returns the default POA for this servant.
virtual PortableServer::POA_ptr _default_POA (
ACE_ENV_SINGLE_ARG_DECL_WITH_DEFAULTS
);
/// Initialize the LoadMinimum instance with the given properties.
void init (const PortableGroup::Properties & props
ACE_ENV_ARG_DECL);
protected:
/// Destructor.
~TAO_LB_LoadMinimum (void);
/// Retrieve the least loaded location from the given list of
/// locations.
CORBA::Boolean get_location (CosLoadBalancing::LoadManager_ptr load_manager,
const PortableGroup::Locations & locations,
PortableGroup::Location & location
ACE_ENV_ARG_DECL);
/// Return the effective load.
CORBA::Float effective_load (CORBA::Float previous_load,
CORBA::Float new_load);
/// Push the new load into this Strategy's load processor, and
/// return the corresponding effective load.
void push_loads (
const PortableGroup::Location & the_location,
const CosLoadBalancing::LoadList & loads,
CosLoadBalancing::Load & effective_load
ACE_ENV_ARG_DECL);
/// Utility method to extract a CORBA::Float value from the given
/// property.
void extract_float_property (const PortableGroup::Property & property,
CORBA::Float & value
ACE_ENV_ARG_DECL);
private:
/// This servant's default POA.
PortableServer::POA_var poa_;
/// Table that maps location to load list.
TAO_LB_LoadMap * load_map_;
/// Lock used to ensure atomic access to state retained by this
/// class.
TAO_SYNCH_MUTEX * lock_;
/// Cached set of properties used when initializing this strategy.
CosLoadBalancing::Properties properties_;
/**
* @name LoadMinimum Property Values
*
* Cached LoadMinimum load balancing strategy property values.
*/
//@{
///
CORBA::Float tolerance_;
///
CORBA::Float dampening_;
///
CORBA::Float per_balance_load_;
//@}
};
#if defined (__ACE_INLINE__)
#include "LB_LoadMinimum.inl"
#endif /* defined INLINE */
#include /**/ "ace/post.h"
#endif /* LB_LOAD_MINIMUM_H */
|
