Fix DFS frequency caluclation.

- having repeater_none_t running at default_core_frequency was messing up
the timestep calculation in global_step().
- added a check for repeater_default and DFS, which are incompatible.
- fixed reversed frequency calculation in McPAT integration.

Change-Id: I88326bdd9ef5a7fa0c719ba1a1b9ae6933bf4d53

ZCOMPS-repeater/repeater-none.cpp

@@ -23,9 +23,20 @@ if(!strcasecmp(COMPONENT_NAME,type))
 }
 
 #else
+
+extern double LLC_speed;
+
 class repeater_none_t: public repeater_t {
   public:
-    repeater_none_t(struct core_t * const _core, const char * const _name, struct cache_t * const _next_level) : repeater_t (_core, _name, _next_level) { speed = _core->knobs->default_cpu_speed; };
+    repeater_none_t(struct core_t * const _core, const char * const _name, struct cache_t * const _next_level) :
+        repeater_t (_core, _name, _next_level)
+      {
+        // Run at uncore speeds. This is important for correct DFS timing calculations
+        // in global_step().
+        // The real repeater implementation (repeater_default_t) has to run at core
+        // speeds, so we have to rethink its clock domains if we want DFS to work with it.
+        speed = LLC_speed;
+      }
     virtual void step() { };
     virtual int enqueuable(const enum cache_command cmd, const int asid, const md_addr_t addr) { return true; }
     virtual void enqueue(const enum cache_command cmd,

sim-slave.cpp

@@ -340,6 +340,10 @@ sim_post_init(void)
     cores[i]->vf_controller = vf_controller_create(knobs.dvfs_opt_str,cores[i]);
   }
 
+  if (strcasecmp(knobs.dvfs_opt_str, "none") &&
+      strcasecmp(knobs.exec.repeater_opt_str,"none"))
+    fatal("DVFS is not compatible with the memory repeater.");
+
   // Time between updating global state (uncore, different nocs)
   sync_interval = MIN(1e-3 / LLC_speed, 1e-3 / cores[0]->memory.mem_repeater->speed);
 

zesto-power.cpp

@@ -391,7 +391,10 @@ void core_power_t::translate_stats(struct stat_sdb_t* sdb, system_core *core_sta
 
   struct core_knobs_t* knobs = core->knobs;
   (void) L2_stats;
-  core_stats->vdd = 1.0;
+  //XXX: Ignore McPAT's DVFS calculation for now. We do our own scaling in
+  // compute_power(). That is, until we can validate that McPAT is doing
+  // more or less the right thing.
+  core_stats->vdd = core_power_t::default_vdd;
 
   stat = stat_find_core_stat(sdb, coreID, "oracle_total_uops");
   core_stats->total_instructions = stat->variant.for_sqword.end_val;
@@ -413,7 +416,7 @@ void core_power_t::translate_stats(struct stat_sdb_t* sdb, system_core *core_sta
 
   // get average frequency for this period
   stat = stat_find_stat(sdb, "sim_cycle");
-  core_stats->clock_rate = (int) ceil(stat->variant.for_sqword.end_val * knobs->default_cpu_speed / (double) core_stats->total_cycles);
+  core_stats->clock_rate = (int) ceil(core_stats->total_cycles * knobs->default_cpu_speed / (double) stat->variant.for_sqword.end_val);
 
   core_stats->idle_cycles = 0;
   core_stats->busy_cycles = core_stats->total_cycles - core_stats->idle_cycles;