From 3187c59183c0082522d4df676156855f699de8d4 Mon Sep 17 00:00:00 2001
From: Lukas Steiner <lsteiner@rhrk.uni-kl.de>
Date: Wed, 20 Jan 2021 11:30:37 +0100
Subject: [PATCH] Stagger refresh on different ranks.

---
 .../refresh/RefreshManagerAllBank.cpp         |  3 +-
 .../src/controller/refresh/RefreshManagerIF.h | 30 +++++++++++++++++++
 .../refresh/RefreshManagerPerBank.cpp         |  3 +-
 .../refresh/RefreshManagerSameBank.cpp        |  3 +-
 4 files changed, 36 insertions(+), 3 deletions(-)

diff --git a/DRAMSys/library/src/controller/refresh/RefreshManagerAllBank.cpp b/DRAMSys/library/src/controller/refresh/RefreshManagerAllBank.cpp
index 63d41ee2..c6e50e3e 100644
--- a/DRAMSys/library/src/controller/refresh/RefreshManagerAllBank.cpp
+++ b/DRAMSys/library/src/controller/refresh/RefreshManagerAllBank.cpp
@@ -45,7 +45,8 @@ RefreshManagerAllBank::RefreshManagerAllBank(std::vector<BankMachine *> &bankMac
 {
     Configuration &config = Configuration::getInstance();
     memSpec = config.memSpec;
-    timeForNextTrigger = memSpec->getRefreshIntervalAB();
+    timeForNextTrigger = getTimeForFirstTrigger(memSpec->getRefreshIntervalAB(),
+                                                rank, memSpec->numberOfRanks);
     setUpDummy(refreshPayload, 0, rank);
 
     maxPostponed = static_cast<int>(config.refreshMaxPostponed);
diff --git a/DRAMSys/library/src/controller/refresh/RefreshManagerIF.h b/DRAMSys/library/src/controller/refresh/RefreshManagerIF.h
index e404037e..3f6684f8 100644
--- a/DRAMSys/library/src/controller/refresh/RefreshManagerIF.h
+++ b/DRAMSys/library/src/controller/refresh/RefreshManagerIF.h
@@ -39,6 +39,7 @@
 #include <tlm.h>
 #include <utility>
 #include "../Command.h"
+#include "../../configuration/Configuration.h"
 
 class RefreshManagerIF
 {
@@ -48,6 +49,35 @@ public:
     virtual CommandTuple::Type getNextCommand() = 0;
     virtual sc_time start() = 0;
     virtual void updateState(Command) = 0;
+
+protected:
+    sc_time getTimeForFirstTrigger(sc_time refreshInterval, Rank rank, unsigned numberOfRanks)
+    {
+        // Calculate bit-reversal rank ID
+        unsigned rankID = rank.ID();
+        unsigned reverseRankID = 0;
+        unsigned rankBits = 0;
+        unsigned rankShift = numberOfRanks;
+
+        while (rankShift >>= 1)
+            rankBits++;
+
+        rankBits--;
+
+        while (rankID != 0)
+        {
+            reverseRankID |= (rankID & 1) << rankBits;
+            rankID >>= 1;
+            rankBits--;
+        }
+
+        // Use bit-reversal order for refreshes on ranks
+        sc_time timeForFirstTrigger = refreshInterval - reverseRankID * (refreshInterval / numberOfRanks);
+        sc_time tCK = Configuration::getInstance().memSpec->tCK;
+        timeForFirstTrigger = std::ceil(timeForFirstTrigger / tCK) * tCK;
+
+        return timeForFirstTrigger;
+    }
 };
 
 #endif // REFRESHMANAGERIF_H
diff --git a/DRAMSys/library/src/controller/refresh/RefreshManagerPerBank.cpp b/DRAMSys/library/src/controller/refresh/RefreshManagerPerBank.cpp
index 236ce8c6..484d063b 100644
--- a/DRAMSys/library/src/controller/refresh/RefreshManagerPerBank.cpp
+++ b/DRAMSys/library/src/controller/refresh/RefreshManagerPerBank.cpp
@@ -45,7 +45,8 @@ RefreshManagerPerBank::RefreshManagerPerBank(std::vector<BankMachine *> &bankMac
 {
     Configuration &config = Configuration::getInstance();
     memSpec = config.memSpec;
-    timeForNextTrigger = memSpec->getRefreshIntervalPB();
+    timeForNextTrigger = getTimeForFirstTrigger(memSpec->getRefreshIntervalPB(),
+                                                rank, memSpec->numberOfRanks);
 
     refreshPayloads = std::vector<tlm_generic_payload>(memSpec->banksPerRank);
     for (unsigned bankID = 0; bankID < memSpec->banksPerRank; bankID++)
diff --git a/DRAMSys/library/src/controller/refresh/RefreshManagerSameBank.cpp b/DRAMSys/library/src/controller/refresh/RefreshManagerSameBank.cpp
index e1d5c7fb..8b5210e3 100644
--- a/DRAMSys/library/src/controller/refresh/RefreshManagerSameBank.cpp
+++ b/DRAMSys/library/src/controller/refresh/RefreshManagerSameBank.cpp
@@ -45,7 +45,8 @@ RefreshManagerSameBank::RefreshManagerSameBank(std::vector<BankMachine *> &bankM
 {
     Configuration &config = Configuration::getInstance();
     memSpec = config.memSpec;
-    timeForNextTrigger = memSpec->getRefreshIntervalSB();
+    timeForNextTrigger = getTimeForFirstTrigger(memSpec->getRefreshIntervalSB(),
+                                                rank, memSpec->numberOfRanks);
 
     refreshPayloads = std::vector<tlm_generic_payload>(memSpec->banksPerGroup);
     for (unsigned bankID = 0; bankID < memSpec->banksPerGroup; bankID++)