1 files changed, 67 insertions, 0 deletions
diff --git a/src/cpu/activity.hh b/src/cpu/activity.hh
new file mode 100644
index 000000000..2d53dc4bb
--- /dev/null
+++ b/src/cpu/activity.hh
@@ -0,0 +1,67 @@
+
+#ifndef __CPU_ACTIVITY_HH__
+#define __CPU_ACTIVITY_HH__
+
+#include "base/timebuf.hh"
+#include "base/trace.hh"
+
+class ActivityRecorder {
+  public:
+    ActivityRecorder(int num_stages, int longest_latency, int count);
+
+    /** Records that there is activity this cycle. */
+    void activity();
+    /** Advances the activity buffer, decrementing the activityCount if active
+     *  communication just left the time buffer, and descheduling the CPU if
+     *  there is no activity.
+     */
+    void advance();
+    /** Marks a stage as active. */
+    void activateStage(const int idx);
+    /** Deactivates a stage. */
+    void deactivateStage(const int idx);
+
+    int getActivityCount() { return activityCount; }
+
+    void setActivityCount(int count)
+    { activityCount = count; }
+
+    bool active() { return activityCount; }
+
+    void reset();
+
+    void dump();
+
+    void validate();
+
+  private:
+    /** Time buffer that tracks if any cycles has active communication
+     *  in them.  It should be as long as the longest communication
+     *  latency in the system.  Each time any time buffer is written,
+     *  the activity buffer should also be written to. The
+     *  activityBuffer is advanced along with all the other time
+     *  buffers, so it should have a 1 somewhere in it only if there
+     *  is active communication in a time buffer.
+     */
+    TimeBuffer<bool> activityBuffer;
+
+    int longestLatency;
+
+    /** Tracks how many stages and cycles of time buffer have
+     *  activity. Stages increment this count when they switch to
+     *  active, and decrement it when they switch to
+     *  inactive. Whenever a cycle that previously had no information
+     *  is written in the time buffer, this is incremented. When a
+     *  cycle that had information exits the time buffer due to age,
+     *  this count is decremented. When the count is 0, there is no
+     *  activity in the CPU, and it can be descheduled.
+     */
+    int activityCount;
+
+    int numStages;
+
+    /** Records which stages are active/inactive. */
+    bool *stageActive;
+};
+
+#endif // __CPU_ACTIVITY_HH__