activity.hh revision 2325 
1
2#ifndef __CPU_ACTIVITY_HH__
3#define __CPU_ACTIVITY_HH__
4
5#include "base/timebuf.hh"
6#include "base/trace.hh"
7
8class ActivityRecorder {
9  public:
10    ActivityRecorder(int num_stages, int longest_latency, int count);
11
12    /** Records that there is activity this cycle. */
13    void activity();
14    /** Advances the activity buffer, decrementing the activityCount if active
15     *  communication just left the time buffer, and descheduling the CPU if
16     *  there is no activity.
17     */
18    void advance();
19    /** Marks a stage as active. */
20    void activateStage(const int idx);
21    /** Deactivates a stage. */
22    void deactivateStage(const int idx);
23
24    int getActivityCount() { return activityCount; }
25
26    void setActivityCount(int count)
27    { activityCount = count; }
28
29    bool active() { return activityCount; }
30
31    void reset();
32
33    void dump();
34
35    void validate();
36
37  private:
38    /** Time buffer that tracks if any cycles has active communication
39     *  in them.  It should be as long as the longest communication
40     *  latency in the system.  Each time any time buffer is written,
41     *  the activity buffer should also be written to. The
42     *  activityBuffer is advanced along with all the other time
43     *  buffers, so it should have a 1 somewhere in it only if there
44     *  is active communication in a time buffer.
45     */
46    TimeBuffer<bool> activityBuffer;
47
48    int longestLatency;
49
50    /** Tracks how many stages and cycles of time buffer have
51     *  activity. Stages increment this count when they switch to
52     *  active, and decrement it when they switch to
53     *  inactive. Whenever a cycle that previously had no information
54     *  is written in the time buffer, this is incremented. When a
55     *  cycle that had information exits the time buffer due to age,
56     *  this count is decremented. When the count is 0, there is no
57     *  activity in the CPU, and it can be descheduled.
58     */
59    int activityCount;
60
61    int numStages;
62
63    /** Records which stages are active/inactive. */
64    bool *stageActive;
65};
66
67#endif // __CPU_ACTIVITY_HH__
68