mem-cache: Upgrade Compressor::Multi's stats

Use new style stats API for Compressor::Multi's stats.

Change-Id: Ia0313704cae4e7bd6bc675c71ea75b42a8e542f2
Signed-off-by: Daniel R. Carvalho <odanrc@yahoo.com.br>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/33377
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>
diff --git a/src/mem/cache/compressors/multi.cc b/src/mem/cache/compressors/multi.cc
index f42602e..229c3b9 100644
--- a/src/mem/cache/compressors/multi.cc
+++ b/src/mem/cache/compressors/multi.cc
@@ -37,6 +37,7 @@
 #include <queue>
 
 #include "base/bitfield.hh"
+#include "base/logging.hh"
 #include "base/trace.hh"
 #include "debug/CacheComp.hh"
 #include "params/MultiCompressor.hh"
@@ -57,7 +58,8 @@
 }
 
 Multi::Multi(const Params *p)
-    : Base(p), compressors(p->compressors)
+  : Base(p), compressors(p->compressors),
+    multiStats(stats, *this)
 {
     fatal_if(compressors.size() == 0, "There must be at least one compressor");
 }
@@ -137,7 +139,7 @@
 
     // Update compressor ranking stats
     for (int rank = 0; rank < compressors.size(); rank++) {
-        rankStats[results.top()->index][rank]++;
+        multiStats.ranks[results.top()->index][rank]++;
         results.pop();
     }
 
@@ -158,23 +160,26 @@
         casted_comp_data->compData.get(), cache_line);
 }
 
-void
-Multi::regStats()
+Multi::MultiStats::MultiStats(BaseStats& base_group, Multi& _compressor)
+  : Stats::Group(&base_group), compressor(_compressor),
+    ranks(this, "ranks",
+        "Number of times each compressor had the nth best compression")
 {
-    Base::regStats();
+}
 
-    rankStats
-        .init(compressors.size(), compressors.size())
-        .name(name() + ".rank")
-        .desc("Number of times each compressor had the nth best compression.")
-        ;
+void
+Multi::MultiStats::regStats()
+{
+    Stats::Group::regStats();
 
-    for (int compressor = 0; compressor < compressors.size(); compressor++) {
-        rankStats.subname(compressor, std::to_string(compressor));
-        rankStats.subdesc(compressor, "Number of times compressor " +
+    const std::size_t num_compressors = compressor.compressors.size();
+    ranks.init(num_compressors, num_compressors);
+    for (unsigned compressor = 0; compressor < num_compressors; compressor++) {
+        ranks.subname(compressor, std::to_string(compressor));
+        ranks.subdesc(compressor, "Number of times compressor " +
             std::to_string(compressor) + " had the nth best compression.");
-        for (unsigned rank = 0; rank < compressors.size(); rank++) {
-            rankStats.ysubname(rank, std::to_string(rank));
+        for (unsigned rank = 0; rank < num_compressors; rank++) {
+            ranks.ysubname(rank, std::to_string(rank));
         }
     }
 }
diff --git a/src/mem/cache/compressors/multi.hh b/src/mem/cache/compressors/multi.hh
index db4f376..06af978 100644
--- a/src/mem/cache/compressors/multi.hh
+++ b/src/mem/cache/compressors/multi.hh
@@ -37,6 +37,7 @@
 #include <cstdint>
 #include <vector>
 
+#include "base/statistics.hh"
 #include "base/types.hh"
 #include "mem/cache/compressors/base.hh"
 
@@ -57,25 +58,25 @@
     /** List of sub-compressors. */
     std::vector<Base*> compressors;
 
-    /**
-     * @defgroup CompressionStats Compression specific statistics.
-     * @{
-     */
+    struct MultiStats : public Stats::Group
+    {
+        const Multi& compressor;
 
-    /** Number of times each compressor provided the nth best compression. */
-    Stats::Vector2d rankStats;
+        MultiStats(BaseStats &base_group, Multi& _compressor);
 
-    /**
-     * @}
-     */
+        void regStats() override;
+
+        /**
+         * Number of times each compressor provided the nth best compression.
+         */
+        Stats::Vector2d ranks;
+    } multiStats;
 
   public:
     typedef MultiCompressorParams Params;
     Multi(const Params *p);
     ~Multi();
 
-    void regStats() override;
-
     std::unique_ptr<Base::CompressionData> compress(
         const uint64_t* data, Cycles& comp_lat, Cycles& decomp_lat) override;