cpu-o3: delete pending wake events if cancel

If this instruction is cancelled, the associated wake event should be descheduled. Change-Id: Ib4c325f42de5874c4cc8c40c4389b9c8985df9f3
OpenXiangShan · Jan 11, 2025 · cf13024 · cf13024
1 parent 79cacc0
commit cf13024
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Showing 2 changed files with 23 additions and 6 deletions.
diff --git a/src/cpu/o3/issue_queue.cc b/src/cpu/o3/issue_queue.cc
@@ -215,7 +215,7 @@ IssueQue::checkScoreboard(const DynInstPtr& inst)
         if (!scheduler->bypassScoreboard[src->flatIndex()]) [[unlikely]] {
             auto dst_inst = scheduler->getInstByDstReg(src->flatIndex());
             if (!dst_inst || !dst_inst->isLoad()) {
-                panic("dst is not load");
+                panic("dst[sn:%llu] is not load", dst_inst->seqNum);
             }
             scheduler->loadCancel(dst_inst);
             DPRINTF(Schedule, "[sn:%llu] %s can't get data from bypassNetwork, dst inst: %s\n", inst->seqNum,
@@ -606,15 +606,16 @@ IssueQue::doSquash(const InstSeqNum seqNum)
     }
 }
 
-Scheduler::SpecWakeupCompletion::SpecWakeupCompletion(const DynInstPtr& inst, IssueQue* to)
-    : Event(Stat_Event_Pri, AutoDelete), inst(inst), to_issue_queue(to)
+Scheduler::SpecWakeupCompletion::SpecWakeupCompletion(const DynInstPtr& inst, IssueQue* to, Scheduler* scheduler)
+    : Event(Stat_Event_Pri, AutoDelete), inst(inst), scheduler(scheduler), to_issue_queue(to)
 {
 }
 
 void
 Scheduler::SpecWakeupCompletion::process()
 {
     to_issue_queue->wakeUpDependents(inst, true);
+    scheduler->specWakeEvents.erase(this);
 }
 
 const char*
@@ -913,7 +914,9 @@ Scheduler::specWakeUpDependents(const DynInstPtr& inst, IssueQue* from_issue_que
                 }
             }
         } else {
-            auto wakeEvent = new SpecWakeupCompletion(inst, to);
+            auto wakeEvent = new SpecWakeupCompletion(inst, to, this);
+            // track these pending events
+            specWakeEvents.insert(wakeEvent);
             cpu->schedule(wakeEvent, cpu->clockEdge(Cycles(wakeDelay)) - 1);
         }
     }
@@ -983,6 +986,16 @@ Scheduler::loadCancel(const DynInstPtr& inst)
     while (!dfs.empty()) {
         auto top = dfs.top();
         dfs.pop();
+        // clear pending wake events scheduled by top
+        for (auto it = specWakeEvents.begin(); it != specWakeEvents.end();) {
+            auto e = *it;
+            if (e->inst == top) {
+                cpu->deschedule(e);
+                it = specWakeEvents.erase(it);
+            } else {
+                it++;
+            }
+        }
         for (int i = 0; i < top->numDestRegs(); i++) {
             auto dst = top->renamedDestIdx(i);
             if (dst->isFixedMapping()) {

diff --git a/src/cpu/o3/issue_queue.hh b/src/cpu/o3/issue_queue.hh
@@ -4,6 +4,7 @@
 #include <cstdint>
 #include <list>
 #include <string>
+#include <unordered_set>
 
 #include <boost/compute/detail/lru_cache.hpp>
 #include <boost/dynamic_bitset/dynamic_bitset.hpp>
@@ -193,11 +194,12 @@ class Scheduler : public SimObject
     friend class IssueQue;
     class SpecWakeupCompletion : public Event
     {
+      public:
         DynInstPtr inst;
+        Scheduler* scheduler;
         IssueQue* to_issue_queue = nullptr;
 
-      public:
-        SpecWakeupCompletion(const DynInstPtr& inst, IssueQue* to);
+        SpecWakeupCompletion(const DynInstPtr& inst, IssueQue* to, Scheduler* scheduler);
         void process() override;
         const char* description() const override;
     };
@@ -245,6 +247,8 @@ class Scheduler : public SimObject
     void specWakeUpDependents(const DynInstPtr& inst, IssueQue* from_issue_queue);
 
   public:
+    std::unordered_set<SpecWakeupCompletion*> specWakeEvents;
+
     Scheduler(const SchedulerParams& params);
     void setCPU(CPU* cpu);
     void resetDepGraph(uint64_t numPhysRegs);