1/* 2 * Copyright (c) 2006 The Regents of The University of Michigan 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions are 7 * met: redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer; 9 * redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution; 12 * neither the name of the copyright holders nor the names of its 13 * contributors may be used to endorse or promote products derived from 14 * this software without specific prior written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 17 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 18 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 19 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 20 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 * 28 * Authors: Kevin Lim 29 */ 30 31#ifndef __CPU_ACTIVITY_HH__ 32#define __CPU_ACTIVITY_HH__ 33 34#include "base/timebuf.hh" 35#include "base/trace.hh" 36 37/** 38 * ActivityRecorder helper class that informs the CPU if it can switch 39 * over to being idle or not. It works by having a time buffer as 40 * long as any time buffer in the CPU, and the CPU and all of its 41 * stages inform the ActivityRecorder when they write to any time 42 * buffer. The ActivityRecorder marks a 1 in the "0" slot of the time 43 * buffer any time a stage writes to a time buffer, and it advances 44 * its time buffer at the same time as all other stages. The 45 * ActivityRecorder also records if a stage has activity to do next 46 * cycle. The recorder keeps a count of these two. Thus any time the 47 * count is non-zero, there is either communication still in flight, 48 * or activity that still must be done, meaning that the CPU can not 49 * idle. If count is zero, then the CPU can safely idle as it has no 50 * more outstanding work to do. 51 */
| 1/* 2 * Copyright (c) 2006 The Regents of The University of Michigan 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions are 7 * met: redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer; 9 * redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution; 12 * neither the name of the copyright holders nor the names of its 13 * contributors may be used to endorse or promote products derived from 14 * this software without specific prior written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 17 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 18 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 19 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 20 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 * 28 * Authors: Kevin Lim 29 */ 30 31#ifndef __CPU_ACTIVITY_HH__ 32#define __CPU_ACTIVITY_HH__ 33 34#include "base/timebuf.hh" 35#include "base/trace.hh" 36 37/** 38 * ActivityRecorder helper class that informs the CPU if it can switch 39 * over to being idle or not. It works by having a time buffer as 40 * long as any time buffer in the CPU, and the CPU and all of its 41 * stages inform the ActivityRecorder when they write to any time 42 * buffer. The ActivityRecorder marks a 1 in the "0" slot of the time 43 * buffer any time a stage writes to a time buffer, and it advances 44 * its time buffer at the same time as all other stages. The 45 * ActivityRecorder also records if a stage has activity to do next 46 * cycle. The recorder keeps a count of these two. Thus any time the 47 * count is non-zero, there is either communication still in flight, 48 * or activity that still must be done, meaning that the CPU can not 49 * idle. If count is zero, then the CPU can safely idle as it has no 50 * more outstanding work to do. 51 */
|
55 56 /** Records that there is activity this cycle. */ 57 void activity(); 58 59 /** Advances the activity buffer, decrementing the activityCount 60 * if active communication just left the time buffer, and 61 * determining if there is no activity. 62 */ 63 void advance(); 64 65 /** Marks a stage as active. */ 66 void activateStage(const int idx); 67 68 /** Deactivates a stage. */ 69 void deactivateStage(const int idx); 70 71 /** Returns how many things are active within the recorder. */ 72 int getActivityCount() { return activityCount; } 73 74 /** Sets the count to a starting value. Can be used to disable 75 * the idling option. 76 */ 77 void setActivityCount(int count) 78 { activityCount = count; } 79 80 /** Returns if the CPU should be active. */ 81 bool active() { return activityCount; } 82 83 /** Clears the time buffer and the activity count. */ 84 void reset(); 85 86 /** Debug function to dump the contents of the time buffer. */ 87 void dump(); 88 89 /** Debug function to ensure that the activity count matches the 90 * contents of the time buffer. 91 */ 92 void validate(); 93 94 private:
| 57 58 /** Records that there is activity this cycle. */ 59 void activity(); 60 61 /** Advances the activity buffer, decrementing the activityCount 62 * if active communication just left the time buffer, and 63 * determining if there is no activity. 64 */ 65 void advance(); 66 67 /** Marks a stage as active. */ 68 void activateStage(const int idx); 69 70 /** Deactivates a stage. */ 71 void deactivateStage(const int idx); 72 73 /** Returns how many things are active within the recorder. */ 74 int getActivityCount() { return activityCount; } 75 76 /** Sets the count to a starting value. Can be used to disable 77 * the idling option. 78 */ 79 void setActivityCount(int count) 80 { activityCount = count; } 81 82 /** Returns if the CPU should be active. */ 83 bool active() { return activityCount; } 84 85 /** Clears the time buffer and the activity count. */ 86 void reset(); 87 88 /** Debug function to dump the contents of the time buffer. */ 89 void dump(); 90 91 /** Debug function to ensure that the activity count matches the 92 * contents of the time buffer. 93 */ 94 void validate(); 95 96 private:
|
95 /** Time buffer that tracks if any cycles has active communication 96 * in them. It should be as long as the longest communication 97 * latency in the system. Each time any time buffer is written, 98 * the activity buffer should also be written to. The 99 * activityBuffer is advanced along with all the other time 100 * buffers, so it should have a 1 somewhere in it only if there 101 * is active communication in a time buffer. 102 */ 103 TimeBuffer<bool> activityBuffer; 104 105 /** Longest latency time buffer in the CPU. */ 106 int longestLatency; 107 108 /** Tracks how many stages and cycles of time buffer have 109 * activity. Stages increment this count when they switch to 110 * active, and decrement it when they switch to 111 * inactive. Whenever a cycle that previously had no information 112 * is written in the time buffer, this is incremented. When a 113 * cycle that had information exits the time buffer due to age, 114 * this count is decremented. When the count is 0, there is no 115 * activity in the CPU, and it can be descheduled. 116 */ 117 int activityCount; 118 119 /** Number of stages that can be marked as active or inactive. */ 120 int numStages; 121 122 /** Records which stages are active/inactive. */ 123 bool *stageActive; 124}; 125 126#endif // __CPU_ACTIVITY_HH__
| 101 /** Time buffer that tracks if any cycles has active communication 102 * in them. It should be as long as the longest communication 103 * latency in the system. Each time any time buffer is written, 104 * the activity buffer should also be written to. The 105 * activityBuffer is advanced along with all the other time 106 * buffers, so it should have a 1 somewhere in it only if there 107 * is active communication in a time buffer. 108 */ 109 TimeBuffer<bool> activityBuffer; 110 111 /** Longest latency time buffer in the CPU. */ 112 int longestLatency; 113 114 /** Tracks how many stages and cycles of time buffer have 115 * activity. Stages increment this count when they switch to 116 * active, and decrement it when they switch to 117 * inactive. Whenever a cycle that previously had no information 118 * is written in the time buffer, this is incremented. When a 119 * cycle that had information exits the time buffer due to age, 120 * this count is decremented. When the count is 0, there is no 121 * activity in the CPU, and it can be descheduled. 122 */ 123 int activityCount; 124 125 /** Number of stages that can be marked as active or inactive. */ 126 int numStages; 127 128 /** Records which stages are active/inactive. */ 129 bool *stageActive; 130}; 131 132#endif // __CPU_ACTIVITY_HH__
|