From 7d362ac6914f6563c1a1531eaa34ae0428ae821a Mon Sep 17 00:00:00 2001
From: Wei Song <wsong83@gmail.com>
Date: Thu, 27 Jun 2024 13:50:03 +0800
Subject: [PATCH] make the pending finish transaction db work with MT

---
 cache/coherence.hpp  | 15 ++++-------
 util/multithread.hpp | 61 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 66 insertions(+), 10 deletions(-)

diff --git a/cache/coherence.hpp b/cache/coherence.hpp
index a5fa171..071e6f7 100644
--- a/cache/coherence.hpp
+++ b/cache/coherence.hpp
@@ -302,16 +302,13 @@ template<class IPUC, bool EnMT> requires C_DERIVE<IPUC, InnerCohPortUncached<EnM
 class InnerCohPortT : public IPUC
 {
 private:
-  // record the pending finish message from inner caches
-  // replace the single storage to a set in multi-thread sim
-  uint64_t addr_pending_finish;
-  int32_t  id_pending_finish;
+  PendingXact<EnMT> pending_xact; // record the pending finish message from inner caches
 protected:
   using InnerCohPortBase::coh;
   using InnerCohPortBase::outer;
   using InnerCohPortBase::policy;
 public:
-  InnerCohPortT(policy_ptr policy) : IPUC(policy), addr_pending_finish(0) {}
+  InnerCohPortT(policy_ptr policy) : IPUC(policy) {}
   virtual ~InnerCohPortT() {}
 
   virtual std::pair<bool, bool> probe_req(uint64_t addr, CMMetadataBase *meta, CMDataBase *data, coh_cmd_t cmd, uint64_t *delay) {
@@ -329,16 +326,14 @@ class InnerCohPortT : public IPUC
 
   // record pending finish
   virtual void finish_record(uint64_t addr, coh_cmd_t outer_cmd) {
-    addr_pending_finish = addr;
-    id_pending_finish = outer_cmd.id;
+    pending_xact.insert(addr, outer_cmd.id);
   }
 
   // only forward the finish message recorded by previous acquire
   virtual void finish_resp(uint64_t addr, coh_cmd_t outer_cmd) {
-    assert(addr_pending_finish == 0 || (addr_pending_finish == addr && id_pending_finish == outer_cmd.id));
-    if(addr_pending_finish == addr && id_pending_finish == outer_cmd.id) {
+    if(pending_xact.count(addr, outer_cmd.id)) {
       outer->finish_req(addr);
-      addr_pending_finish = 0;
+      pending_xact.remove(addr, outer_cmd.id);
     }
   }
 };
diff --git a/util/multithread.hpp b/util/multithread.hpp
index 3491a23..1df8f81 100644
--- a/util/multithread.hpp
+++ b/util/multithread.hpp
@@ -1,6 +1,9 @@
 #ifndef CM_UTIL_MULTITHREAD_HPP
 #define CM_UTIL_MULTITHREAD_HPP
 
+#include <unordered_map>
+#include <cstdint>
+#include <cassert>
 #include <atomic>
 #include <mutex>
 #include <condition_variable>
@@ -48,4 +51,62 @@ class AtomicVar {
   }
 };
 
+// a database for recoridng the pending transactions
+template<bool EnMT>
+class PendingXact {
+  std::unordered_map<uint64_t, uint64_t> db;
+  std::mutex mtx;
+public:
+  PendingXact() {}
+  virtual ~PendingXact() {}
+
+  void insert(uint64_t addr, uint32_t id) {
+    std::lock_guard lk(mtx);
+    if(!db.count(addr)) db[addr] = 0;
+    assert(0ull == (db[addr] & (1ull << id)) || 0 ==
+           "The to be inserted <addr, id> pair has already been inserted in the database!");
+    db[addr] |= (1ull << id);
+  }
+
+  void remove(uint64_t addr, uint32_t id) {
+    std::lock_guard lk(mtx);
+    if(db.count(addr)) {
+      db[addr] &= ~(1ull << id);
+      if(db[addr] == 0) db.erase(addr);
+    }
+  }
+
+  bool count(uint64_t addr, uint32_t id) {
+    std::lock_guard lk(mtx);
+    return db.count(addr) && (db[addr] & (1ull << id));
+  }
+};
+
+// specialization for non-multithread env
+template<>
+class PendingXact<false> {
+
+  uint64_t addr;
+  int32_t  id;
+
+public:
+  PendingXact(): addr(0), id(0) {}
+  virtual ~PendingXact() {}
+
+  void insert(uint64_t addr, uint32_t id) {
+    this->addr = addr;
+    this->id = id;
+  }
+
+  void remove(uint64_t addr, uint32_t id) {
+    if(count(addr, id)) this->addr = 0;
+  }
+
+  bool count(uint64_t addr, uint32_t id) {
+    return this->addr == addr && this->id == id;
+  }
+};
+
+
+
 #endif