cpu: Delegate comInstEventQueue methods to the ThreadContexts.

These then just use the comInstEventQueue array from the CPU, but soon
they will actually be self contained and allow the thread context to
use whatever mechanism it wants.

Also, now that the thread contexts need to exist before instruction
count based events can be scheduled, setting up max instruction based
events needs to happen in init after the CPU subclasses have had a
chance to set up the threadContexts vector.

Change-Id: I34bb401633d277a60be74e30d5a478a149b972ea
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/22108
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>

src/cpu/base.cc

@@ -162,43 +162,6 @@ BaseCPU::BaseCPU(Params *p, bool is_checker)
         comInstEventQueue[tid] =
             new EventQueue("instruction-based event queue");
 
-    //
-    // set up instruction-count-based termination events, if any
-    //
-    if (p->max_insts_any_thread != 0) {
-        const char *cause = "a thread reached the max instruction count";
-        for (ThreadID tid = 0; tid < numThreads; ++tid)
-            scheduleInstStop(tid, p->max_insts_any_thread, cause);
-    }
-
-    // Set up instruction-count-based termination events for SimPoints
-    // Typically, there are more than one action points.
-    // Simulation.py is responsible to take the necessary actions upon
-    // exitting the simulation loop.
-    if (!p->simpoint_start_insts.empty()) {
-        const char *cause = "simpoint starting point found";
-        for (size_t i = 0; i < p->simpoint_start_insts.size(); ++i)
-            scheduleInstStop(0, p->simpoint_start_insts[i], cause);
-    }
-
-    if (p->max_insts_all_threads != 0) {
-        const char *cause = "all threads reached the max instruction count";
-
-        // allocate & initialize shared downcounter: each event will
-        // decrement this when triggered; simulation will terminate
-        // when counter reaches 0
-        int *counter = new int;
-        *counter = numThreads;
-        for (ThreadID tid = 0; tid < numThreads; ++tid) {
-            Event *event = new CountedExitEvent(cause, *counter);
-            scheduleInstCountEvent(tid, event, p->max_insts_all_threads);
-        }
-    }
-
-    //
-    // set up instruction-count-based termination events, if any
-    //
-
     functionTracingEnabled = false;
     if (p->function_trace) {
         const string fname = csprintf("ftrace.%s", name());
@@ -323,6 +286,39 @@ BaseCPU::mwaitAtomic(ThreadID tid, ThreadContext *tc, BaseTLB *dtb)
 void
 BaseCPU::init()
 {
+    // Set up instruction-count-based termination events, if any. This needs
+    // to happen after threadContexts has been constructed.
+    if (params()->max_insts_any_thread != 0) {
+        const char *cause = "a thread reached the max instruction count";
+        for (ThreadID tid = 0; tid < numThreads; ++tid)
+            scheduleInstStop(tid, params()->max_insts_any_thread, cause);
+    }
+
+    // Set up instruction-count-based termination events for SimPoints
+    // Typically, there are more than one action points.
+    // Simulation.py is responsible to take the necessary actions upon
+    // exitting the simulation loop.
+    if (!params()->simpoint_start_insts.empty()) {
+        const char *cause = "simpoint starting point found";
+        for (size_t i = 0; i < params()->simpoint_start_insts.size(); ++i)
+            scheduleInstStop(0, params()->simpoint_start_insts[i], cause);
+    }
+
+    if (params()->max_insts_all_threads != 0) {
+        const char *cause = "all threads reached the max instruction count";
+
+        // allocate & initialize shared downcounter: each event will
+        // decrement this when triggered; simulation will terminate
+        // when counter reaches 0
+        int *counter = new int;
+        *counter = numThreads;
+        for (ThreadID tid = 0; tid < numThreads; ++tid) {
+            Event *event = new CountedExitEvent(cause, *counter);
+            scheduleInstCountEvent(
+                    tid, event, params()->max_insts_all_threads);
+        }
+    }
+
     if (!params()->switched_out) {
         registerThreadContexts();
 
@@ -735,7 +731,7 @@ BaseCPU::scheduleInstStop(ThreadID tid, Counter insts, const char *cause)
 Tick
 BaseCPU::getCurrentInstCount(ThreadID tid)
 {
-    return comInstEventQueue[tid]->getCurTick();
+    return threadContexts[tid]->getCurrentInstCount();
 }
 
 AddressMonitor::AddressMonitor() {

src/cpu/base.hh

@@ -468,26 +468,25 @@ class BaseCPU : public ClockedObject
     Tick
     nextInstEventCount(ThreadID tid)
     {
-        return comInstEventQueue[tid]->empty() ?
-            MaxTick : comInstEventQueue[tid]->nextTick();
+        return threadContexts[tid]->nextInstEventCount();
     }
 
     void
     serviceInstCountEvents(ThreadID tid, Tick count)
     {
-        comInstEventQueue[tid]->serviceEvents(count);
+        threadContexts[tid]->serviceInstCountEvents(count);
     }
 
     void
     scheduleInstCountEvent(ThreadID tid, Event *event, Tick count)
     {
-        comInstEventQueue[tid]->schedule(event, count);
+        threadContexts[tid]->scheduleInstCountEvent(event, count);
     }
 
     void
     descheduleInstCountEvent(ThreadID tid, Event *event)
     {
-        comInstEventQueue[tid]->deschedule(event);
+        threadContexts[tid]->descheduleInstCountEvent(event);
     }
 
   public:

src/cpu/thread_context.cc

@@ -55,6 +55,41 @@
 #include "params/BaseCPU.hh"
 #include "sim/full_system.hh"
 
+Tick
+ThreadContext::nextInstEventCount()
+{
+    auto *queue = getCpuPtr()->comInstEventQueue[threadId()];
+    return queue->empty() ? MaxTick : queue->nextTick();
+}
+
+void
+ThreadContext::serviceInstCountEvents(Tick count)
+{
+    auto *queue = getCpuPtr()->comInstEventQueue[threadId()];
+    queue->serviceEvents(count);
+}
+
+void
+ThreadContext::scheduleInstCountEvent(Event *event, Tick count)
+{
+    auto *queue = getCpuPtr()->comInstEventQueue[threadId()];
+    return queue->schedule(event, count);
+}
+
+void
+ThreadContext::descheduleInstCountEvent(Event *event)
+{
+    auto *queue = getCpuPtr()->comInstEventQueue[threadId()];
+    queue->deschedule(event);
+}
+
+Tick
+ThreadContext::getCurrentInstCount()
+{
+    auto *queue = getCpuPtr()->comInstEventQueue[threadId()];
+    return queue->getCurTick();
+}
+
 void
 ThreadContext::compare(ThreadContext *one, ThreadContext *two)
 {

src/cpu/thread_context.hh

@@ -192,6 +192,12 @@ class ThreadContext : public PCEventScope
 
     virtual EndQuiesceEvent *getQuiesceEvent() = 0;
 
+    virtual Tick nextInstEventCount();
+    virtual void serviceInstCountEvents(Tick count);
+    virtual void scheduleInstCountEvent(Event *event, Tick count);
+    virtual void descheduleInstCountEvent(Event *event);
+    virtual Tick getCurrentInstCount();
+
     // Not necessarily the best location for these...
     // Having an extra function just to read these is obnoxious
     virtual Tick readLastActivate() = 0;