alpha,arm,mips,power,x86,cpu,sim: Cleanup activate/deactivate

activate(), suspend(), and halt() used on thread contexts had an optional
delay parameter. However this parameter was often ignored. Also, when used,
the delay was seemily arbitrarily set to 0 or 1 cycle (no other delays were
ever specified). This patch removes the delay parameter and 'Events'
associated with them across all ISAs and cores. Unused activate logic
is also removed.

5 files changed, 27 insertions, 339 deletions

diff --git a/src/cpu/o3/cpu.cc b/src/cpu/o3/cpu.cc
index fdbbd5c14..2ae185532 100644
--- a/src/cpu/o3/cpu.cc
+++ b/src/cpu/o3/cpu.cc
@@ -148,67 +148,6 @@ FullO3CPU<Impl>::TickEvent::description() const
 }
 
 template <class Impl>
-FullO3CPU<Impl>::ActivateThreadEvent::ActivateThreadEvent()
-    : Event(CPU_Switch_Pri)
-{
-}
-
-template <class Impl>
-void
-FullO3CPU<Impl>::ActivateThreadEvent::init(int thread_num,
-                                           FullO3CPU<Impl> *thread_cpu)
-{
-    tid = thread_num;
-    cpu = thread_cpu;
-}
-
-template <class Impl>
-void
-FullO3CPU<Impl>::ActivateThreadEvent::process()
-{
-    cpu->activateThread(tid);
-}
-
-template <class Impl>
-const char *
-FullO3CPU<Impl>::ActivateThreadEvent::description() const
-{
-    return "FullO3CPU \"Activate Thread\"";
-}
-
-template <class Impl>
-FullO3CPU<Impl>::DeallocateContextEvent::DeallocateContextEvent()
-    : Event(CPU_Tick_Pri), tid(0), remove(false), cpu(NULL)
-{
-}
-
-template <class Impl>
-void
-FullO3CPU<Impl>::DeallocateContextEvent::init(int thread_num,
-                                              FullO3CPU<Impl> *thread_cpu)
-{
-    tid = thread_num;
-    cpu = thread_cpu;
-    remove = false;
-}
-
-template <class Impl>
-void
-FullO3CPU<Impl>::DeallocateContextEvent::process()
-{
-    cpu->deactivateThread(tid);
-    if (remove)
-        cpu->removeThread(tid);
-}
-
-template <class Impl>
-const char *
-FullO3CPU<Impl>::DeallocateContextEvent::description() const
-{
-    return "FullO3CPU \"Deallocate Context\"";
-}
-
-template <class Impl>
 FullO3CPU<Impl>::FullO3CPU(DerivO3CPUParams *params)
     : BaseO3CPU(params),
       itb(params->itb),
@@ -346,9 +285,6 @@ FullO3CPU<Impl>::FullO3CPU(DerivO3CPUParams *params)
 
         renameMap[tid].init(&regFile, TheISA::ZeroReg, fpZeroReg,
                             &freeList);
-
-        activateThreadEvent[tid].init(tid, this);
-        deallocateContextEvent[tid].init(tid, this);
     }
 
     // Initialize rename map to assign physical registers to the
@@ -389,7 +325,6 @@ FullO3CPU<Impl>::FullO3CPU(DerivO3CPUParams *params)
         globalSeqNum[tid] = 1;
 #endif
 
-    contextSwitch = false;
     DPRINTF(O3CPU, "Creating O3CPU object.\n");
 
     // Setup any thread state.
@@ -613,9 +548,6 @@ FullO3CPU<Impl>::tick()
 
     commit.tick();
 
-    if (!FullSystem)
-        doContextSwitch();
-
     // Now advance the time buffers
     timeBuffer.advance();
 
@@ -761,18 +693,12 @@ FullO3CPU<Impl>::totalOps() const
 
 template <class Impl>
 void
-FullO3CPU<Impl>::activateContext(ThreadID tid, Cycles delay)
+FullO3CPU<Impl>::activateContext(ThreadID tid)
 {
     assert(!switchedOut());
 
     // Needs to set each stage to running as well.
-    if (delay){
-        DPRINTF(O3CPU, "[tid:%i]: Scheduling thread context to activate "
-                "on cycle %d\n", tid, clockEdge(delay));
-        scheduleActivateThreadEvent(tid, delay);
-    } else {
-        activateThread(tid);
-    }
+    activateThread(tid);
 
     // We don't want to wake the CPU if it is drained. In that case,
     // we just want to flag the thread as active and schedule the tick
@@ -783,7 +709,7 @@ FullO3CPU<Impl>::activateContext(ThreadID tid, Cycles delay)
     // If we are time 0 or if the last activation time is in the past,
     // schedule the next tick and wake up the fetch unit
     if (lastActivatedCycle == 0 || lastActivatedCycle < curTick()) {
-        scheduleTickEvent(delay);
+        scheduleTickEvent(Cycles(0));
 
         // Be sure to signal that there's some activity so the CPU doesn't
         // deschedule itself.
@@ -803,22 +729,12 @@ FullO3CPU<Impl>::activateContext(ThreadID tid, Cycles delay)
 }
 
 template <class Impl>
-bool
-FullO3CPU<Impl>::scheduleDeallocateContext(ThreadID tid, bool remove,
-                                           Cycles delay)
-{
-    // Schedule removal of thread data from CPU
-    if (delay){
-        DPRINTF(O3CPU, "[tid:%i]: Scheduling thread context to deallocate "
-                "on tick %d\n", tid, clockEdge(delay));
-        scheduleDeallocateContextEvent(tid, remove, delay);
-        return false;
-    } else {
-        deactivateThread(tid);
-        if (remove)
-            removeThread(tid);
-        return true;
-    }
+void
+FullO3CPU<Impl>::deallocateContext(ThreadID tid, bool remove)
+{
+    deactivateThread(tid);
+    if (remove)
+        removeThread(tid);
 }
 
 template <class Impl>
@@ -827,10 +743,10 @@ FullO3CPU<Impl>::suspendContext(ThreadID tid)
 {
     DPRINTF(O3CPU,"[tid: %i]: Suspending Thread Context.\n", tid);
     assert(!switchedOut());
-    bool deallocated = scheduleDeallocateContext(tid, false, Cycles(1));
+    deallocateContext(tid, false);
+
     // If this was the last thread then unschedule the tick event.
-    if ((activeThreads.size() == 1 && !deallocated) ||
-        activeThreads.size() == 0)
+    if (activeThreads.size() == 0)
         unscheduleTickEvent();
 
     DPRINTF(Quiesce, "Suspending Context\n");
@@ -845,7 +761,7 @@ FullO3CPU<Impl>::haltContext(ThreadID tid)
     //For now, this is the same as deallocate
     DPRINTF(O3CPU,"[tid:%i]: Halt Context called. Deallocating", tid);
     assert(!switchedOut());
-    scheduleDeallocateContext(tid, true, Cycles(1));
+    deallocateContext(tid, true);
 }
 
 template <class Impl>
@@ -896,7 +812,7 @@ FullO3CPU<Impl>::insertThread(ThreadID tid)
 
     src_tc->setStatus(ThreadContext::Active);
 
-    activateContext(tid, Cycles(1));
+    activateContext(tid);
 
     //Reset ROB/IQ/LSQ Entries
     commit.rob->resetEntries();
@@ -973,77 +889,6 @@ FullO3CPU<Impl>::removeThread(ThreadID tid)
 */
 }
 
-
-template <class Impl>
-void
-FullO3CPU<Impl>::activateWhenReady(ThreadID tid)
-{
-    DPRINTF(O3CPU,"[tid:%i]: Checking if resources are available for incoming"
-            "(e.g. PhysRegs/ROB/IQ/LSQ) \n",
-            tid);
-
-    bool ready = true;
-
-    // Should these all be '<' not '>='?  This seems backwards...
-    if (freeList.numFreeIntRegs() >= TheISA::NumIntRegs) {
-        DPRINTF(O3CPU,"[tid:%i] Suspending thread due to not enough "
-                "Phys. Int. Regs.\n",
-                tid);
-        ready = false;
-    } else if (freeList.numFreeFloatRegs() >= TheISA::NumFloatRegs) {
-        DPRINTF(O3CPU,"[tid:%i] Suspending thread due to not enough "
-                "Phys. Float. Regs.\n",
-                tid);
-        ready = false;
-    } else if (freeList.numFreeCCRegs() >= TheISA::NumCCRegs) {
-        DPRINTF(O3CPU,"[tid:%i] Suspending thread due to not enough "
-                "Phys. CC. Regs.\n",
-                tid);
-        ready = false;
-    } else if (commit.rob->numFreeEntries() >=
-               commit.rob->entryAmount(activeThreads.size() + 1)) {
-        DPRINTF(O3CPU,"[tid:%i] Suspending thread due to not enough "
-                "ROB entries.\n",
-                tid);
-        ready = false;
-    } else if (iew.instQueue.numFreeEntries() >=
-               iew.instQueue.entryAmount(activeThreads.size() + 1)) {
-        DPRINTF(O3CPU,"[tid:%i] Suspending thread due to not enough "
-                "IQ entries.\n",
-                tid);
-        ready = false;
-    } else if (iew.ldstQueue.numFreeLoadEntries() >=
-               iew.ldstQueue.entryAmount(activeThreads.size() + 1)) {
-        DPRINTF(O3CPU,"[tid:%i] Suspending thread due to not enough "
-                "LQ entries.\n",
-                tid);
-        ready = false;
-    } else if (iew.ldstQueue.numFreeStoreEntries() >=
-            iew.ldstQueue.entryAmount(activeThreads.size() + 1)) {
-        DPRINTF(O3CPU,"[tid:%i] Suspending thread due to not enough "
-                "SQ entries.\n",
-             tid);
-        ready = false;
-    }
-
-    if (ready) {
-        insertThread(tid);
-
-        contextSwitch = false;
-
-        cpuWaitList.remove(tid);
-    } else {
-        suspendContext(tid);
-
-        //blocks fetch
-        contextSwitch = true;
-
-        //@todo: dont always add to waitlist
-        //do waitlist
-        cpuWaitList.push_back(tid);
-    }
-}
-
 template <class Impl>
 Fault
 FullO3CPU<Impl>::hwrei(ThreadID tid)
@@ -1243,19 +1088,6 @@ FullO3CPU<Impl>::isDrained() const
 {
     bool drained(true);
 
-    for (ThreadID i = 0; i < thread.size(); ++i) {
-        if (activateThreadEvent[i].scheduled()) {
-            DPRINTF(Drain, "CPU not drained, tread %i has a "
-                    "pending activate event\n", i);
-            drained = false;
-        }
-        if (deallocateContextEvent[i].scheduled()) {
-            DPRINTF(Drain, "CPU not drained, tread %i has a "
-                    "pending deallocate context event\n", i);
-            drained = false;
-        }
-    }
-
     if (!instList.empty() || !removeList.empty()) {
         DPRINTF(Drain, "Main CPU structures not drained.\n");
         drained = false;
@@ -1832,24 +1664,6 @@ FullO3CPU<Impl>::getFreeTid()
 
 template <class Impl>
 void
-FullO3CPU<Impl>::doContextSwitch()
-{
-    if (contextSwitch) {
-
-        //ADD CODE TO DEACTIVE THREAD HERE (???)
-
-        ThreadID size = cpuWaitList.size();
-        for (ThreadID tid = 0; tid < size; tid++) {
-            activateWhenReady(tid);
-        }
-
-        if (cpuWaitList.size() == 0)
-            contextSwitch = true;
-    }
-}
-
-template <class Impl>
-void
 FullO3CPU<Impl>::updateThreadPriority()
 {
     if (activeThreads.size() > 1) {
diff --git a/src/cpu/o3/cpu.hh b/src/cpu/o3/cpu.hh
index cfed216c3..0fd08a68b 100644
--- a/src/cpu/o3/cpu.hh
+++ b/src/cpu/o3/cpu.hh
@@ -229,116 +229,6 @@ class FullO3CPU : public BaseO3CPU
             tickEvent.squash();
     }
 
-    class ActivateThreadEvent : public Event
-    {
-      private:
-        /** Number of Thread to Activate */
-        ThreadID tid;
-
-        /** Pointer to the CPU. */
-        FullO3CPU<Impl> *cpu;
-
-      public:
-        /** Constructs the event. */
-        ActivateThreadEvent();
-
-        /** Initialize Event */
-        void init(int thread_num, FullO3CPU<Impl> *thread_cpu);
-
-        /** Processes the event, calling activateThread() on the CPU. */
-        void process();
-
-        /** Returns the description of the event. */
-        const char *description() const;
-    };
-
-    /** Schedule thread to activate , regardless of its current state. */
-    void
-    scheduleActivateThreadEvent(ThreadID tid, Cycles delay)
-    {
-        // Schedule thread to activate, regardless of its current state.
-        if (activateThreadEvent[tid].squashed())
-            reschedule(activateThreadEvent[tid],
-                       clockEdge(delay));
-        else if (!activateThreadEvent[tid].scheduled()) {
-            Tick when = clockEdge(delay);
-
-            // Check if the deallocateEvent is also scheduled, and make
-            // sure they do not happen at same time causing a sleep that
-            // is never woken from.
-            if (deallocateContextEvent[tid].scheduled() &&
-                deallocateContextEvent[tid].when() == when) {
-                when++;
-            }
-
-            schedule(activateThreadEvent[tid], when);
-        }
-    }
-
-    /** Unschedule actiavte thread event, regardless of its current state. */
-    void
-    unscheduleActivateThreadEvent(ThreadID tid)
-    {
-        if (activateThreadEvent[tid].scheduled())
-            activateThreadEvent[tid].squash();
-    }
-
-    /** The tick event used for scheduling CPU ticks. */
-    ActivateThreadEvent activateThreadEvent[Impl::MaxThreads];
-
-    class DeallocateContextEvent : public Event
-    {
-      private:
-        /** Number of Thread to deactivate */
-        ThreadID tid;
-
-        /** Should the thread be removed from the CPU? */
-        bool remove;
-
-        /** Pointer to the CPU. */
-        FullO3CPU<Impl> *cpu;
-
-      public:
-        /** Constructs the event. */
-        DeallocateContextEvent();
-
-        /** Initialize Event */
-        void init(int thread_num, FullO3CPU<Impl> *thread_cpu);
-
-        /** Processes the event, calling activateThread() on the CPU. */
-        void process();
-
-        /** Sets whether the thread should also be removed from the CPU. */
-        void setRemove(bool _remove) { remove = _remove; }
-
-        /** Returns the description of the event. */
-        const char *description() const;
-    };
-
-    /** Schedule cpu to deallocate thread context.*/
-    void
-    scheduleDeallocateContextEvent(ThreadID tid, bool remove, Cycles delay)
-    {
-        // Schedule thread to activate, regardless of its current state.
-        if (deallocateContextEvent[tid].squashed())
-            reschedule(deallocateContextEvent[tid],
-                       clockEdge(delay));
-        else if (!deallocateContextEvent[tid].scheduled())
-            schedule(deallocateContextEvent[tid],
-                     clockEdge(delay));
-    }
-
-    /** Unschedule thread deallocation in CPU */
-    void
-    unscheduleDeallocateContextEvent(ThreadID tid)
-    {
-        if (deallocateContextEvent[tid].scheduled())
-            deallocateContextEvent[tid].squash();
-    }
-
-    /** The tick event used for scheduling CPU ticks. */
-    DeallocateContextEvent deallocateContextEvent[Impl::MaxThreads];
-
     /**
      * Check if the pipeline has drained and signal the DrainManager.
      *
@@ -430,7 +320,7 @@ class FullO3CPU : public BaseO3CPU
     virtual Counter totalOps() const;
 
     /** Add Thread to Active Threads List. */
-    void activateContext(ThreadID tid, Cycles delay);
+    void activateContext(ThreadID tid);
 
     /** Remove Thread from Active Threads List */
     void suspendContext(ThreadID tid);
@@ -438,20 +328,13 @@ class FullO3CPU : public BaseO3CPU
     /** Remove Thread from Active Threads List &&
      *  Possibly Remove Thread Context from CPU.
      */
-    bool scheduleDeallocateContext(ThreadID tid, bool remove,
-                                   Cycles delay = Cycles(1));
+    void deallocateContext(ThreadID tid, bool remove);
 
     /** Remove Thread from Active Threads List &&
      *  Remove Thread Context from CPU.
      */
     void haltContext(ThreadID tid);
 
-    /** Activate a Thread When CPU Resources are Available. */
-    void activateWhenReady(ThreadID tid);
-
-    /** Add or Remove a Thread Context in the CPU. */
-    void doContextSwitch();
-
     /** Update The Order In Which We Process Threads. */
     void updateThreadPriority();
 
@@ -792,9 +675,6 @@ class FullO3CPU : public BaseO3CPU
     /** Pointers to all of the threads in the CPU. */
     std::vector<Thread *> thread;
 
-    /** Is there a context switch pending? */
-    bool contextSwitch;
-
     /** Threads Scheduled to Enter CPU */
     std::list<int> cpuWaitList;
 
diff --git a/src/cpu/o3/fetch_impl.hh b/src/cpu/o3/fetch_impl.hh
index b9e3b78c5..7319b38a5 100644
--- a/src/cpu/o3/fetch_impl.hh
+++ b/src/cpu/o3/fetch_impl.hh
@@ -811,10 +811,7 @@ DefaultFetch<Impl>::checkStall(ThreadID tid) const
 {
     bool ret_val = false;
 
-    if (cpu->contextSwitch) {
-        DPRINTF(Fetch,"[tid:%i]: Stalling for a context switch.\n",tid);
-        ret_val = true;
-    } else if (stalls[tid].drain) {
+    if (stalls[tid].drain) {
         assert(cpu->isDraining());
         DPRINTF(Fetch,"[tid:%i]: Drain stall detected.\n",tid);
         ret_val = true;
@@ -970,9 +967,8 @@ DefaultFetch<Impl>::tick()
     }
 
     // If there was activity this cycle, inform the CPU of it.
-    if (wroteToTimeBuffer || cpu->contextSwitch) {
+    if (wroteToTimeBuffer) {
         DPRINTF(Activity, "Activity this cycle.\n");
-
         cpu->activityThisCycle();
     }
 
diff --git a/src/cpu/o3/thread_context.hh b/src/cpu/o3/thread_context.hh
index a00d2ffa3..b27fbb386 100755
--- a/src/cpu/o3/thread_context.hh
+++ b/src/cpu/o3/thread_context.hh
@@ -136,15 +136,14 @@ class O3ThreadContext : public ThreadContext
     virtual void setStatus(Status new_status)
     { thread->setStatus(new_status); }
 
-    /** Set the status to Active.  Optional delay indicates number of
-     * cycles to wait before beginning execution. */
-    virtual void activate(Cycles delay = Cycles(1));
+    /** Set the status to Active. */
+    virtual void activate();
 
     /** Set the status to Suspended. */
-    virtual void suspend(Cycles delay = Cycles(0));
+    virtual void suspend();
 
     /** Set the status to Halted. */
-    virtual void halt(Cycles delay = Cycles(0));
+    virtual void halt();
 
     /** Dumps the function profiling information.
      * @todo: Implement.
diff --git a/src/cpu/o3/thread_context_impl.hh b/src/cpu/o3/thread_context_impl.hh
index 43e903135..e6a3d5083 100755
--- a/src/cpu/o3/thread_context_impl.hh
+++ b/src/cpu/o3/thread_context_impl.hh
@@ -84,7 +84,7 @@ O3ThreadContext<Impl>::takeOverFrom(ThreadContext *old_context)
 
 template <class Impl>
 void
-O3ThreadContext<Impl>::activate(Cycles delay)
+O3ThreadContext<Impl>::activate()
 {
     DPRINTF(O3CPU, "Calling activate on Thread Context %d\n",
             threadId());
@@ -96,12 +96,12 @@ O3ThreadContext<Impl>::activate(Cycles delay)
     thread->setStatus(ThreadContext::Active);
 
     // status() == Suspended
-    cpu->activateContext(thread->threadId(), delay);
+    cpu->activateContext(thread->threadId());
 }
 
 template <class Impl>
 void
-O3ThreadContext<Impl>::suspend(Cycles delay)
+O3ThreadContext<Impl>::suspend()
 {
     DPRINTF(O3CPU, "Calling suspend on Thread Context %d\n",
             threadId());
@@ -118,10 +118,9 @@ O3ThreadContext<Impl>::suspend(Cycles delay)
 
 template <class Impl>
 void
-O3ThreadContext<Impl>::halt(Cycles delay)
+O3ThreadContext<Impl>::halt()
 {
-    DPRINTF(O3CPU, "Calling halt on Thread Context %d\n",
-            threadId());
+    DPRINTF(O3CPU, "Calling halt on Thread Context %d\n", threadId());
 
     if (thread->status() == ThreadContext::Halted)
         return;