Mercurial > hg > graal-compiler
annotate src/share/vm/utilities/yieldingWorkgroup.hpp @ 1847:a932f331ef90
6991065: missed a review comment in 6829194
Reviewed-by: kvn
author | twisti |
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date | Tue, 12 Oct 2010 02:21:06 -0700 |
parents | c18cbe5936b8 |
children | 8b10f48633dc |
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0 | 1 /* |
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2 * Copyright (c) 2005, Oracle and/or its affiliates. All rights reserved. |
0 | 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
4 * | |
5 * This code is free software; you can redistribute it and/or modify it | |
6 * under the terms of the GNU General Public License version 2 only, as | |
7 * published by the Free Software Foundation. | |
8 * | |
9 * This code is distributed in the hope that it will be useful, but WITHOUT | |
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
12 * version 2 for more details (a copy is included in the LICENSE file that | |
13 * accompanied this code). | |
14 * | |
15 * You should have received a copy of the GNU General Public License version | |
16 * 2 along with this work; if not, write to the Free Software Foundation, | |
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
18 * | |
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
0 | 22 * |
23 */ | |
24 | |
25 | |
26 // Forward declarations | |
27 class YieldingFlexibleWorkGang; | |
28 | |
29 // Status of tasks | |
30 enum Status { | |
31 INACTIVE, | |
32 ACTIVE, | |
33 YIELDING, | |
34 YIELDED, | |
35 ABORTING, | |
36 ABORTED, | |
37 COMPLETING, | |
38 COMPLETED | |
39 }; | |
40 | |
41 // Class YieldingFlexibleGangWorker: | |
42 // Several instances of this class run in parallel as workers for a gang. | |
43 class YieldingFlexibleGangWorker: public GangWorker { | |
44 public: | |
45 // Ctor | |
46 YieldingFlexibleGangWorker(AbstractWorkGang* gang, int id) : | |
47 GangWorker(gang, id) { } | |
48 | |
49 public: | |
50 YieldingFlexibleWorkGang* yf_gang() const | |
51 { return (YieldingFlexibleWorkGang*)gang(); } | |
52 | |
53 protected: // Override from parent class | |
54 virtual void loop(); | |
55 }; | |
56 | |
57 // An abstract task to be worked on by a flexible work gang, | |
58 // and where the workers will periodically yield, usually | |
59 // in response to some condition that is signalled by means | |
60 // that are specific to the task at hand. | |
61 // You subclass this to supply your own work() method. | |
62 // A second feature of this kind of work gang is that | |
63 // it allows for the signalling of certain exceptional | |
64 // conditions that may be encountered during the performance | |
65 // of the task and that may require the task at hand to be | |
66 // `aborted' forthwith. Finally, these gangs are `flexible' | |
67 // in that they can operate at partial capacity with some | |
68 // gang workers waiting on the bench; in other words, the | |
69 // size of the active worker pool can flex (up to an apriori | |
70 // maximum) in response to task requests at certain points. | |
71 // The last part (the flexible part) has not yet been fully | |
72 // fleshed out and is a work in progress. | |
73 class YieldingFlexibleGangTask: public AbstractGangTask { | |
74 Status _status; | |
75 YieldingFlexibleWorkGang* _gang; | |
76 int _actual_size; // size of gang obtained | |
77 | |
78 protected: | |
79 int _requested_size; // size of gang requested | |
80 | |
81 // Constructor and desctructor: only construct subclasses. | |
82 YieldingFlexibleGangTask(const char* name): AbstractGangTask(name), | |
83 _status(INACTIVE), | |
84 _gang(NULL), | |
85 _requested_size(0) { } | |
86 | |
87 virtual ~YieldingFlexibleGangTask() { } | |
88 | |
89 friend class YieldingFlexibleWorkGang; | |
90 friend class YieldingFlexibleGangWorker; | |
91 NOT_PRODUCT(virtual bool is_YieldingFlexibleGang_task() const { | |
92 return true; | |
93 }) | |
94 | |
95 void set_status(Status s) { | |
96 _status = s; | |
97 } | |
98 YieldingFlexibleWorkGang* gang() { | |
99 return _gang; | |
100 } | |
101 void set_gang(YieldingFlexibleWorkGang* gang) { | |
102 assert(_gang == NULL || gang == NULL, "Clobber without intermediate reset?"); | |
103 _gang = gang; | |
104 } | |
105 | |
106 public: | |
107 // The abstract work method. | |
108 // The argument tells you which member of the gang you are. | |
109 virtual void work(int i) = 0; | |
110 | |
111 // Subclasses should call the parent's yield() method | |
112 // after having done any work specific to the subclass. | |
113 virtual void yield(); | |
114 | |
115 // An abstract method supplied by | |
116 // a concrete sub-class which is used by the coordinator | |
117 // to do any "central yielding" work. | |
118 virtual void coordinator_yield() = 0; | |
119 | |
120 // Subclasses should call the parent's abort() method | |
121 // after having done any work specific to the sunbclass. | |
122 virtual void abort(); | |
123 | |
124 Status status() const { return _status; } | |
125 bool yielded() const { return _status == YIELDED; } | |
126 bool completed() const { return _status == COMPLETED; } | |
127 bool aborted() const { return _status == ABORTED; } | |
128 bool active() const { return _status == ACTIVE; } | |
129 | |
130 int requested_size() const { return _requested_size; } | |
131 int actual_size() const { return _actual_size; } | |
132 | |
133 void set_requested_size(int sz) { _requested_size = sz; } | |
134 void set_actual_size(int sz) { _actual_size = sz; } | |
135 }; | |
136 | |
137 // Class YieldingWorkGang: A subclass of WorkGang. | |
138 // In particular, a YieldingWorkGang is made up of | |
139 // YieldingGangWorkers, and provides infrastructure | |
140 // supporting yielding to the "GangOverseer", | |
141 // being the thread that orchestrates the WorkGang via run_task(). | |
142 class YieldingFlexibleWorkGang: public AbstractWorkGang { | |
143 // Here's the public interface to this class. | |
144 public: | |
145 // Constructor and destructor. | |
342 | 146 YieldingFlexibleWorkGang(const char* name, int workers, |
147 bool are_GC_task_threads); | |
0 | 148 |
149 YieldingFlexibleGangTask* yielding_task() const { | |
150 assert(task() == NULL || task()->is_YieldingFlexibleGang_task(), | |
151 "Incorrect cast"); | |
152 return (YieldingFlexibleGangTask*)task(); | |
153 } | |
154 // Run a task; returns when the task is done, or the workers yield, | |
155 // or the task is aborted, or the work gang is terminated via stop(). | |
156 // A task that has been yielded can be continued via this same interface | |
157 // by using the same task repeatedly as the argument to the call. | |
158 // It is expected that the YieldingFlexibleGangTask carries the appropriate | |
159 // continuation information used by workers to continue the task | |
160 // from its last yield point. Thus, a completed task will return | |
161 // immediately with no actual work having been done by the workers. | |
162 void run_task(AbstractGangTask* task) { | |
163 guarantee(false, "Use start_task instead"); | |
164 } | |
165 void start_task(YieldingFlexibleGangTask* new_task); | |
166 void continue_task(YieldingFlexibleGangTask* gang_task); | |
167 | |
168 // Abort a currently running task, if any; returns when all the workers | |
169 // have stopped working on the current task and have returned to their | |
170 // waiting stations. | |
171 void abort_task(); | |
172 | |
173 // Yield: workers wait at their current working stations | |
174 // until signalled to proceed by the overseer. | |
175 void yield(); | |
176 | |
177 // Abort: workers are expected to return to their waiting | |
178 // stations, whence they are ready for the next task dispatched | |
179 // by the overseer. | |
180 void abort(); | |
181 | |
182 private: | |
183 // The currently active workers in this gang. | |
184 // This is a number that is dynamically adjusted by | |
185 // the run_task() method at each subsequent invocation, | |
186 // using data in the YieldingFlexibleGangTask. | |
187 int _active_workers; | |
188 int _yielded_workers; | |
189 void wait_for_gang(); | |
190 | |
191 public: | |
192 // Accessors for fields | |
193 int active_workers() const { | |
194 return _active_workers; | |
195 } | |
196 | |
197 int yielded_workers() const { | |
198 return _yielded_workers; | |
199 } | |
200 | |
201 private: | |
202 friend class YieldingFlexibleGangWorker; | |
203 void reset(); // NYI | |
204 }; |