From: Nilay Vaish <nilay@cs.wisc.edu>
Date: Mon, 15 Oct 2012 22:27:15 +0000 (-0500)
Subject: ruby banked array: do away with event scheduling
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=c7b0901b97a86eb2d61e4ddd96a73a9d777a57c1;p=gem5.git

ruby banked array: do away with event scheduling
It seems unecessary that the BankedArray class needs to schedule an event
to figure out when the access ends. Instead only the time for the end of access
needs to be tracked.
---

diff --git a/src/mem/ruby/system/BankedArray.cc b/src/mem/ruby/system/BankedArray.cc
index 8af0701a5..df7852a0e 100644
--- a/src/mem/ruby/system/BankedArray.cc
+++ b/src/mem/ruby/system/BankedArray.cc
@@ -29,15 +29,12 @@
  *
  */
 
-#include <vector>
-
 #include "base/intmath.hh"
-#include "mem/ruby/common/TypeDefines.hh"
 #include "mem/ruby/system/BankedArray.hh"
-#include "sim/eventq.hh"
+#include "mem/ruby/system/System.hh"
 
-BankedArray::BankedArray(unsigned int banks, Cycles accessLatency, unsigned int startIndexBit) :
-    EventManager(&mainEventQueue)
+BankedArray::BankedArray(unsigned int banks, Cycles accessLatency,
+                         unsigned int startIndexBit)
 {
     this->banks = banks;
     this->accessLatency = accessLatency;
@@ -59,19 +56,21 @@ BankedArray::tryAccess(Index idx)
     unsigned int bank = mapIndexToBank(idx);
     assert(bank < banks);
 
-    if (busyBanks[bank].scheduled()) {
-        if (!(busyBanks[bank].startAccess == curTick() && busyBanks[bank].idx == idx)) {
+    if (busyBanks[bank].endAccess >= curTick()) {
+        if (!(busyBanks[bank].startAccess == curTick() &&
+            busyBanks[bank].idx == idx)) {
             return false;
         } else {
-            return true;  // We tried to allocate resources twice in the same cycle for the same addr
+            // We tried to allocate resources twice
+            // in the same cycle for the same addr
+            return true;
         }
     }
 
     busyBanks[bank].idx = idx;
     busyBanks[bank].startAccess = curTick();
-
-    // substract 1 so that next cycle the resource available
-    schedule(busyBanks[bank], curTick()+accessLatency-1);
+    busyBanks[bank].endAccess = curTick() +
+        (accessLatency-1) * g_system_ptr->clockPeriod();
 
     return true;
 }
diff --git a/src/mem/ruby/system/BankedArray.hh b/src/mem/ruby/system/BankedArray.hh
index 7ebf39dfb..89007befa 100644
--- a/src/mem/ruby/system/BankedArray.hh
+++ b/src/mem/ruby/system/BankedArray.hh
@@ -35,37 +35,32 @@
 #include <vector>
 
 #include "mem/ruby/common/TypeDefines.hh"
-#include "sim/eventq.hh"
+#include "sim/core.hh"
 
-
-
-class BankedArray : public EventManager
+class BankedArray
 {
-private:
+  private:
     unsigned int banks;
     Cycles accessLatency;
     unsigned int bankBits;
     unsigned int startIndexBit;
 
-    //std::vector<bool> busyBanks;
-
-    class TickEvent : public Event
+    class AccessRecord
     {
-    public:
-        TickEvent() : Event() {}
-        void process() {}
+      public:
+        AccessRecord() : idx(0), startAccess(0), endAccess(0) {}
         Index idx;
         Tick startAccess;
+        Tick endAccess;
     };
-    friend class TickEvent;
 
     // If the tick event is scheduled then the bank is busy
     // otherwise, schedule the event and wait for it to complete
-    std::vector<TickEvent> busyBanks;
+    std::vector<AccessRecord> busyBanks;
 
     unsigned int mapIndexToBank(Index idx);
 
-public:
+  public:
     BankedArray(unsigned int banks, Cycles accessLatency, unsigned int startIndexBit);
 
     // Note: We try the access based on the cache index, not the address