Redesigned the memory partition unit to support multiple L2 cache banks per partition. Each L2 cache banks has its own connection to the interconnection network to allow L2 bandwidth to scale without increase the number of memory parttiion units.

[git-p4: depot-paths = "//depot/gpgpu_sim_research/fermi/distribution/": change = 16613]

1 files changed, 104 insertions, 27 deletions

diff --git a/src/gpgpu-sim/l2cache.h b/src/gpgpu-sim/l2cache.h
index 6ef00a7..07e37ca 100644
--- a/src/gpgpu-sim/l2cache.h
+++ b/src/gpgpu-sim/l2cache.h
@@ -52,9 +52,12 @@ private:
     const memory_config *m_memory_config;
 };
 
-class memory_partition_unit 
+// Memory partition unit contains all the units assolcated with a single DRAM channel. 
+// - It arbitrates the DRAM channel among multiple sub partitions.  
+// - It does not connect directly with the interconnection network. 
+class memory_partition_unit
 {
-public:
+public: 
    memory_partition_unit( unsigned partition_id, const struct memory_config *config, class memory_stats_t *stats );
    ~memory_partition_unit(); 
 
@@ -63,6 +66,93 @@ public:
    void cache_cycle( unsigned cycle );
    void dram_cycle();
 
+   void set_done( mem_fetch *mf );
+
+   void visualizer_print( gzFile visualizer_file ) const;
+   void print_stat( FILE *fp ) { m_dram->print_stat(fp); }
+   void visualize() const { m_dram->visualize(); }
+   void print( FILE *fp ) const;
+
+   class memory_sub_partition * get_sub_partition(int sub_partition_id) 
+   {
+      return m_sub_partition[sub_partition_id]; 
+   }
+
+   // Power model
+   void set_dram_power_stats(unsigned &n_cmd,
+                             unsigned &n_activity,
+                             unsigned &n_nop,
+                             unsigned &n_act,
+                             unsigned &n_pre,
+                             unsigned &n_rd,
+                             unsigned &n_wr,
+                             unsigned &n_req) const;
+
+   int global_sub_partition_id_to_local_id(int global_sub_partition_id) const; 
+
+   unsigned get_mpid() const { return m_id; }
+
+private: 
+
+   unsigned m_id;
+   const struct memory_config *m_config;
+   class memory_stats_t *m_stats;
+   class memory_sub_partition **m_sub_partition; 
+   class dram_t *m_dram;
+
+   class arbitration_metadata
+   {
+   public: 
+      arbitration_metadata(const struct memory_config *config); 
+
+      // check if a subpartition still has credit 
+      bool has_credits(int inner_sub_partition_id) const; 
+      // borrow a credit for a subpartition 
+      void borrow_credit(int inner_sub_partition_id); 
+      // return a credit from a subpartition 
+      void return_credit(int inner_sub_partition_id); 
+
+      // return the last subpartition that borrowed credit 
+      int last_borrower() const { return m_last_borrower; } 
+
+      void print( FILE *fp ) const; 
+   private: 
+      // id of the last subpartition that borrowed credit 
+      int m_last_borrower; 
+
+      int m_shared_credit_limit; 
+      int m_private_credit_limit; 
+
+      // credits borrowed by the subpartitions
+      std::vector<int> m_private_credit; 
+      int m_shared_credit; 
+   }; 
+   arbitration_metadata m_arbitration_metadata; 
+
+   // determine wheither a given subpartition can issue to DRAM 
+   bool can_issue_to_dram(int inner_sub_partition_id); 
+
+   // model DRAM access scheduler latency (fixed latency between L2 and DRAM)
+   struct dram_delay_t
+   {
+      unsigned long long ready_cycle;
+      class mem_fetch* req;
+   };
+   std::queue<dram_delay_t> m_dram_latency_queue;
+};
+
+class memory_sub_partition
+{
+public:
+   memory_sub_partition( unsigned sub_partition_id, const struct memory_config *config, class memory_stats_t *stats );
+   ~memory_sub_partition(); 
+
+   unsigned get_id() const { return m_id; } 
+
+   bool busy() const;
+
+   void cache_cycle( unsigned cycle );
+
    bool full() const;
    void push( class mem_fetch* mf, unsigned long long clock_cycle );
    class mem_fetch* pop(); 
@@ -71,31 +161,26 @@ public:
 
    unsigned flushL2();
 
+   // interface to L2_dram_queue
+   bool L2_dram_queue_empty() const; 
+   class mem_fetch* L2_dram_queue_top() const; 
+   void L2_dram_queue_pop(); 
+
+   // interface to dram_L2_queue
+   bool dram_L2_queue_full() const; 
+   void dram_L2_queue_push( class mem_fetch* mf ); 
+
    void visualizer_print( gzFile visualizer_file );
    void print_cache_stat(unsigned &accesses, unsigned &misses) const;
-   void print_stat( FILE *fp ) { m_dram->print_stat(fp); }
-   void visualize() const { m_dram->visualize(); }
    void print( FILE *fp ) const;
 
-
-   // Power model
-   void set_dram_power_stats(unsigned &n_cmd,
-			unsigned &n_activity,
-			unsigned &n_nop,
-			unsigned &n_act,
-			unsigned &n_pre,
-			unsigned &n_rd,
-			unsigned &n_wr,
-			unsigned &n_req) const;
-
    void accumulate_L2cache_stats(class cache_stats &l2_stats) const;
    void get_L2cache_sub_stats(struct cache_sub_stats &css) const;
 
 private:
 // data
-   unsigned m_id;
+   unsigned m_id;  //< the global sub partition ID
    const struct memory_config *m_config;
-   class dram_t *m_dram;
    class l2_cache *m_L2cache;
    class L2interface *m_L2interface;
    partition_mf_allocator *m_mf_allocator;
@@ -108,14 +193,6 @@ private:
    };
    std::queue<rop_delay_t> m_rop;
 
-   // model DRAM access scheduler latency (fixed latency between L2 and DRAM)
-   struct dram_delay_t
-   {
-      unsigned long long ready_cycle;
-      class mem_fetch* req;
-   };
-   std::queue<dram_delay_t> m_dram_latency_queue;
-
    // these are various FIFOs between units within a memory partition
    fifo_pipeline<mem_fetch> *m_icnt_L2_queue;
    fifo_pipeline<mem_fetch> *m_L2_dram_queue;
@@ -134,7 +211,7 @@ private:
 
 class L2interface : public mem_fetch_interface {
 public:
-    L2interface( memory_partition_unit *unit ) { m_unit=unit; }
+    L2interface( memory_sub_partition *unit ) { m_unit=unit; }
     virtual ~L2interface() {}
     virtual bool full( unsigned size, bool write) const 
     {
@@ -147,7 +224,7 @@ public:
         m_unit->m_L2_dram_queue->push(mf);
     }
 private:
-    memory_partition_unit *m_unit;
+    memory_sub_partition *m_unit;
 };
 
 #endif