Add option to print memory stats in bytes only

Author: igchor

cachelib/cachebench/cache/Cache.cpp

@@ -22,9 +22,10 @@ DEFINE_bool(report_api_latency,
             false,
             "Enable reporting cache API latency tracking");
 
-DEFINE_bool(report_memory_usage_stats,
-            false,
-            "Enable reporting statistics for each allocation class");
+DEFINE_string(report_memory_usage_stats,
+            "",
+            "Enable reporting statistics for each allocation class. Set to"
+            "'human_readable' to print KB/MB/GB or to 'raw' to print in bytes.");
 
 namespace facebook {
 namespace cachelib {

cachelib/cachebench/cache/Cache.h

@@ -44,7 +44,7 @@
 #include "cachelib/cachebench/util/NandWrites.h"
 
 DECLARE_bool(report_api_latency);
-DECLARE_bool(report_memory_usage_stats);
+DECLARE_string(report_memory_usage_stats);
 
 namespace facebook {
 namespace cachelib {

cachelib/cachebench/cache/CacheStats.h

@@ -21,7 +21,7 @@
 #include "cachelib/common/PercentileStats.h"
 
 DECLARE_bool(report_api_latency);
-DECLARE_bool(report_memory_usage_stats);
+DECLARE_string(report_memory_usage_stats);
 
 namespace facebook {
 namespace cachelib {
@@ -135,12 +135,16 @@ struct Stats {
           << std::endl;
     }
 
-    if (FLAGS_report_memory_usage_stats) {
+    if (FLAGS_report_memory_usage_stats != "") {
       for (TierId tid = 0; tid < slabsApproxFreePercentages.size(); tid++) {
         out << folly::sformat("tid{:2} free slabs : {:.2f}%", tid, slabsApproxFreePercentages[tid]) << std::endl;
       }
 
-      auto formatMemory = [](size_t bytes) -> std::tuple<std::string, double> {
+      auto formatMemory = [&](size_t bytes) -> std::tuple<std::string, double> {
+        if (FLAGS_report_memory_usage_stats == "raw") {
+          return {"B", bytes};
+        }
+
         constexpr double KB = 1024.0;
         constexpr double MB = 1024.0 * 1024;
         constexpr double GB = 1024.0 * 1024 * 1024;