[v1.06][X86] Fix accurate-pp in hybrid architectures (fixes #169)

Overview of changes:
- Adds field max_pp in frequency struct to hold the max freq for peak-performance estimation.
- Instead of getting the max frequency in get_peak_performance, we get it in get_cpu_info (more natural).
- Adds fill_frequency_info_pp which fills the max_pp of the passed cpu by calling measure_frequency.

The approach is to call measure_frequency with a vector where the max frequencies are stored. Then,
the first time measure_frequency is called, the frequency is measured while running all the cores,
and the max frequency is computed per module (e.g., in the case of 2 modules, we would compute
the freq for the first and for the second module), and saved into this vector. Subsequent calls to
measure_frequency will just read the corresponding value for the vector. In other words, the frequency
is only measured once for the whole CPU.

src/x86/cpuid.c

@@ -210,18 +210,14 @@ int64_t get_peak_performance(struct cpuInfo* cpu, bool accurate_pp) {
 
   for(int i=0; i < cpu->num_cpus; ptr = ptr->next_cpu, i++) {
     struct topology* topo = ptr->topo;
-    int64_t max_freq = get_freq(ptr->freq);
+    int64_t freq = get_freq(ptr->freq);
 
-    int64_t freq;
   #ifdef __linux__
     if(accurate_pp)
-      freq = measure_frequency(ptr);
-    else
-      freq = max_freq;
+      freq = get_freq_pp(ptr->freq);
   #else
     // Silence compiler warning
     (void)(accurate_pp);
-    freq = max_freq;
   #endif
 
     //First, check we have consistent data
@@ -450,6 +446,23 @@ int32_t get_core_type(void) {
   }
 }
 
+#ifdef __linux__
+// Gets the max frequency for estimating the peak performance,
+// filling in the passed cpuInfo parameter with this information.
+void fill_frequency_info_pp(struct cpuInfo* cpu) {
+  int32_t unused;
+  int32_t *max_freq_pp_vec = malloc(sizeof(int32_t) * cpu->num_cpus);
+  struct cpuInfo* ptr = cpu;
+
+  for (uint32_t i=0; i < cpu->num_cpus; i++) {
+    set_cpu_module(i, cpu->num_cpus, &unused);
+
+    ptr->freq->max_pp = measure_frequency(ptr, max_freq_pp_vec);
+    ptr = ptr->next_cpu;
+  }
+}
+#endif
+
 struct cpuInfo* get_cpu_info(void) {
   struct cpuInfo* cpu = emalloc(sizeof(struct cpuInfo));
   cpu->peak_performance = -1;
@@ -546,6 +559,7 @@ struct cpuInfo* get_cpu_info(void) {
       ptr->core_type = get_core_type();
     }
     ptr->first_core_id = first_core;
+    ptr->module_id = i;
     ptr->feat = get_features_info(ptr);
 
     ptr->arch = get_cpu_uarch(ptr);
@@ -570,6 +584,13 @@ struct cpuInfo* get_cpu_info(void) {
     if(ptr->topo == NULL) return cpu;
   }
 
+#ifdef __linux__
+  // If accurate_pp is requested, we need to get the max frequency
+  // after fetching the topology for all CPU modules, since the topology
+  // is required by fill_frequency_info_pp
+  if (accurate_pp()) fill_frequency_info_pp(cpu);
+#endif
+
   cpu->peak_performance = get_peak_performance(cpu, accurate_pp());
 
   return cpu;
@@ -1005,6 +1026,7 @@ struct frequency* get_frequency_info(struct cpuInfo* cpu) {
     }
   #endif
 
+  freq->max_pp = UNKNOWN_DATA;
   return freq;
 }