Clock: Add a Cycles wrapper class and use where applicable

This patch addresses the comments and feedback on the preceding patch
that reworks the clocks and now more clearly shows where cycles
(relative cycle counts) are used to express time.

Instead of bumping the existing patch I chose to make this a separate
patch, merely to try and focus the discussion around a smaller set of
changes. The two patches will be pushed together though.

This changes done as part of this patch are mostly following directly
from the introduction of the wrapper class, and change enough code to
make things compile and run again. There are definitely more places
where int/uint/Tick is still used to represent cycles, and it will
take some time to chase them all down. Similarly, a lot of parameters
should be changed from Param.Tick and Param.Unsigned to
Param.Cycles.

In addition, the use of curTick is questionable as there should not be
an absolute cycle. Potential solutions can be built on top of this
patch. There is a similar situation in the o3 CPU where
lastRunningCycle is currently counting in Cycles, and is still an
absolute time. More discussion to be had in other words.

An additional change that would be appropriate in the future is to
perform a similar wrapping of Tick and probably also introduce a
Ticks class along with suitable operators for all these classes.

1 files changed, 7 insertions, 6 deletions

diff --git a/src/cpu/o3/cpu.hh b/src/cpu/o3/cpu.hh
index 5910f314d..076cce0fb 100644
--- a/src/cpu/o3/cpu.hh
+++ b/src/cpu/o3/cpu.hh
@@ -211,7 +211,7 @@ class FullO3CPU : public BaseO3CPU
     TickEvent tickEvent;
 
     /** Schedule tick event, regardless of its current state. */
-    void scheduleTickEvent(int delay)
+    void scheduleTickEvent(Cycles delay)
     {
         if (tickEvent.squashed())
             reschedule(tickEvent, clockEdge(delay));
@@ -251,7 +251,7 @@ class FullO3CPU : public BaseO3CPU
 
     /** Schedule thread to activate , regardless of its current state. */
     void
-    scheduleActivateThreadEvent(ThreadID tid, int delay)
+    scheduleActivateThreadEvent(ThreadID tid, Cycles delay)
     {
         // Schedule thread to activate, regardless of its current state.
         if (activateThreadEvent[tid].squashed())
@@ -314,7 +314,7 @@ class FullO3CPU : public BaseO3CPU
 
     /** Schedule cpu to deallocate thread context.*/
     void
-    scheduleDeallocateContextEvent(ThreadID tid, bool remove, int delay)
+    scheduleDeallocateContextEvent(ThreadID tid, bool remove, Cycles delay)
     {
         // Schedule thread to activate, regardless of its current state.
         if (deallocateContextEvent[tid].squashed())
@@ -392,7 +392,7 @@ class FullO3CPU : public BaseO3CPU
     virtual Counter totalOps() const;
 
     /** Add Thread to Active Threads List. */
-    void activateContext(ThreadID tid, int delay);
+    void activateContext(ThreadID tid, Cycles delay);
 
     /** Remove Thread from Active Threads List */
     void suspendContext(ThreadID tid);
@@ -400,7 +400,8 @@ class FullO3CPU : public BaseO3CPU
     /** Remove Thread from Active Threads List &&
      *  Possibly Remove Thread Context from CPU.
      */
-    bool scheduleDeallocateContext(ThreadID tid, bool remove, int delay = 1);
+    bool scheduleDeallocateContext(ThreadID tid, bool remove,
+                                   Cycles delay = Cycles(1));
 
     /** Remove Thread from Active Threads List &&
      *  Remove Thread Context from CPU.
@@ -748,7 +749,7 @@ class FullO3CPU : public BaseO3CPU
     std::list<int> cpuWaitList;
 
     /** The cycle that the CPU was last running, used for statistics. */
-    Tick lastRunningCycle;
+    Cycles lastRunningCycle;
 
     /** The cycle that the CPU was last activated by a new thread*/
     Tick lastActivatedCycle;