diff --git a/src/mem/cache/tags/fa_lru.cc b/src/mem/cache/tags/fa_lru.cc
--- a/src/mem/cache/tags/fa_lru.cc
+++ b/src/mem/cache/tags/fa_lru.cc
@@ -186,6 +186,8 @@
     FALRUBlk* blk = hashLookup(blkAddr);
 
     if (blk && blk->isValid()) {
+        // If a cache hit
+        lat = accessLatency;
         assert(blk->tag == blkAddr);
         tmp_in_cache = blk->inCache;
         for (unsigned i = 0; i < numCaches; i++) {
@@ -200,6 +202,8 @@
             moveToHead(blk);
         }
     } else {
+        // If a cache miss
+        lat = lookupLatency;
         blk = nullptr;
         for (unsigned i = 0; i <= numCaches; ++i) {
             misses[i]++;
@@ -209,7 +213,6 @@
         *inCache = tmp_in_cache;
     }
 
-    lat = accessLatency;
     //assert(check());
     return blk;
 }
# HG changeset patch
# Parent 80e79ae636ca6b021cbf7aa985b5fd56cb5b2708
mem: Split the hit_latency into tag_latency and data_latency

If the cache access mode is parallel, i.e. "sequential_access" parameter
is set to "False", tags and data are accessed in parallel. Therefore,
the hit_latency is the maximum latency between tag_latency and
data_latency. On the other hand, if the cache access mode is
sequential, i.e. "sequential_access" parameter is set to "True",
tags and data are accessed sequentially. Therefore, the hit_latency
is the sum of tag_latency plus data_latency.

diff --git a/configs/common/Caches.py b/configs/common/Caches.py
--- a/configs/common/Caches.py
+++ b/configs/common/Caches.py
@@ -48,7 +48,8 @@
 
 class L1Cache(Cache):
     assoc = 2
-    hit_latency = 2
+    tag_latency = 2
+    data_latency = 2
     response_latency = 2
     mshrs = 4
     tgts_per_mshr = 20
@@ -63,7 +64,8 @@
 
 class L2Cache(Cache):
     assoc = 8
-    hit_latency = 20
+    tag_latency = 20
+    data_latency = 20
     response_latency = 20
     mshrs = 20
     tgts_per_mshr = 12
@@ -71,7 +73,8 @@
 
 class IOCache(Cache):
     assoc = 8
-    hit_latency = 50
+    tag_latency = 50
+    data_latency = 50
     response_latency = 50
     mshrs = 20
     size = '1kB'
@@ -79,7 +82,8 @@
 
 class PageTableWalkerCache(Cache):
     assoc = 2
-    hit_latency = 2
+    tag_latency = 2
+    data_latency = 2
     response_latency = 2
     mshrs = 10
     size = '1kB'
diff --git a/src/mem/cache/Cache.py b/src/mem/cache/Cache.py
--- a/src/mem/cache/Cache.py
+++ b/src/mem/cache/Cache.py
@@ -53,7 +53,8 @@
     size = Param.MemorySize("Capacity")
     assoc = Param.Unsigned("Associativity")
 
-    hit_latency = Param.Cycles("Hit latency")
+    tag_latency = Param.Cycles("Tag lookup latency")
+    data_latency = Param.Cycles("Data access latency")
     response_latency = Param.Cycles("Latency for the return path on a miss");
 
     max_miss_count = Param.Counter(0,
diff --git a/src/mem/cache/base.hh b/src/mem/cache/base.hh
--- a/src/mem/cache/base.hh
+++ b/src/mem/cache/base.hh
@@ -265,6 +265,12 @@
     const Cycles lookupLatency;
 
     /**
+     * The latency of data access of a cache. It occurs when there is
+     * an access to the cache.
+     */
+    const Cycles dataLatency;
+
+    /**
      * This is the forward latency of the cache. It occurs when there
      * is a cache miss and a request is forwarded downstream, in
      * particular an outbound miss.
diff --git a/src/mem/cache/base.cc b/src/mem/cache/base.cc
--- a/src/mem/cache/base.cc
+++ b/src/mem/cache/base.cc
@@ -72,9 +72,10 @@
       mshrQueue("MSHRs", p->mshrs, 0, p->demand_mshr_reserve), // see below
       writeBuffer("write buffer", p->write_buffers, p->mshrs), // see below
       blkSize(blk_size),
-      lookupLatency(p->hit_latency),
-      forwardLatency(p->hit_latency),
-      fillLatency(p->response_latency),
+      lookupLatency(p->tag_latency),
+      dataLatency(p->data_latency),
+      forwardLatency(p->tag_latency),
+      fillLatency(p->data_latency),
       responseLatency(p->response_latency),
       numTarget(p->tgts_per_mshr),
       forwardSnoops(true),
diff --git a/src/mem/cache/tags/Tags.py b/src/mem/cache/tags/Tags.py
--- a/src/mem/cache/tags/Tags.py
+++ b/src/mem/cache/tags/Tags.py
@@ -49,17 +49,22 @@
     # Get the block size from the parent (system)
     block_size = Param.Int(Parent.cache_line_size, "block size in bytes")
 
-    # Get the hit latency from the parent (cache)
-    hit_latency = Param.Cycles(Parent.hit_latency,
-                               "The hit latency for this cache")
+    # Get the tag lookup latency from the parent (cache)
+    tag_latency = Param.Cycles(Parent.tag_latency,
+                               "The tag lookup latency for this cache")
+
+    # Get the RAM access latency from the parent (cache)
+    data_latency = Param.Cycles(Parent.data_latency,
+                               "The data access latency for this cache")
+
+    sequential_access = Param.Bool(Parent.sequential_access,
+        "Whether to access tags and data sequentially")
 
 class BaseSetAssoc(BaseTags):
     type = 'BaseSetAssoc'
     abstract = True
     cxx_header = "mem/cache/tags/base_set_assoc.hh"
     assoc = Param.Int(Parent.assoc, "associativity")
-    sequential_access = Param.Bool(Parent.sequential_access,
-        "Whether to access tags and data sequentially")
 
 class LRU(BaseSetAssoc):
     type = 'LRU'
diff --git a/src/mem/cache/tags/base.hh b/src/mem/cache/tags/base.hh
--- a/src/mem/cache/tags/base.hh
+++ b/src/mem/cache/tags/base.hh
@@ -69,7 +69,15 @@
     const unsigned blkSize;
     /** The size of the cache. */
     const unsigned size;
-    /** The access latency of the cache. */
+    /** The tag lookup latency of the cache. */
+    const Cycles lookupLatency;
+    /** The data access latency of the cache. */
+    const Cycles dataLatency;
+    /**
+     * The total access latency of the cache. This latency
+     * is different depending on the cache access mode
+     * (parallel or sequential)
+     */
     const Cycles accessLatency;
     /** Pointer to the parent cache. */
     BaseCache *cache;
diff --git a/src/mem/cache/tags/base.cc b/src/mem/cache/tags/base.cc
--- a/src/mem/cache/tags/base.cc
+++ b/src/mem/cache/tags/base.cc
@@ -56,7 +56,11 @@
 
 BaseTags::BaseTags(const Params *p)
     : ClockedObject(p), blkSize(p->block_size), size(p->size),
-      accessLatency(p->hit_latency), cache(nullptr), warmupBound(0),
+      lookupLatency(p->tag_latency), dataLatency(p->data_latency),
+      accessLatency(p->sequential_access ?
+                    p->tag_latency + p->data_latency :
+                    std::max(p->tag_latency, p->data_latency)),
+      cache(nullptr), warmupBound(0),
       warmedUp(false), numBlocks(0)
 {
 }
diff --git a/src/mem/cache/tags/base_set_assoc.hh b/src/mem/cache/tags/base_set_assoc.hh
--- a/src/mem/cache/tags/base_set_assoc.hh
+++ b/src/mem/cache/tags/base_set_assoc.hh
@@ -208,7 +208,6 @@
         Addr tag = extractTag(addr);
         int set = extractSet(addr);
         BlkType *blk = sets[set].findBlk(tag, is_secure);
-        lat = accessLatency;;
 
         // Access all tags in parallel, hence one in each way.  The data side
         // either accesses all blocks in parallel, or one block sequentially on
@@ -223,12 +222,17 @@
         }
 
         if (blk != nullptr) {
+            // If a cache hit
+            lat = accessLatency;
             if (blk->whenReady > curTick()
                 && cache->ticksToCycles(blk->whenReady - curTick())
-                > accessLatency) {
+                > lat) {
                 lat = cache->ticksToCycles(blk->whenReady - curTick());
             }
             blk->refCount += 1;
+        } else {
+            // If a cache miss
+            lat = lookupLatency;
         }
 
         return blk;