Add setting to show only active CPUs

Closes: htop-dev#757

CPUMeter.c

@@ -36,6 +36,7 @@ static const int CPUMeter_attributes[] = {
 
 typedef struct CPUMeterData_ {
    unsigned int cpus;
+   unsigned int adjustActive;
    Meter** meters;
 } CPUMeterData;
 
@@ -188,6 +189,7 @@ static void CPUMeter_display(const Object* cast, RichString* out) {
 static void AllCPUsMeter_getRange(const Meter* this, int* start, int* count) {
    const CPUMeterData* data = this->meterData;
    unsigned int cpus = data->cpus;
+   unsigned int adjustActive = data->adjustActive;
    switch(Meter_name(this)[0]) {
       default:
       case 'A': // All
@@ -199,7 +201,7 @@ static void AllCPUsMeter_getRange(const Meter* this, int* start, int* count) {
          *count = (cpus+1) / 2;
          break;
       case 'R': // Second Half
-         *start = (cpus+1) / 2;
+         *start = (cpus+1) / 2 + adjustActive;
          *count = cpus / 2;
          break;
    }
@@ -214,20 +216,54 @@ static void AllCPUsMeter_updateValues(Meter* this) {
       Meter_updateValues(meters[i]);
 }
 
+static void AllCPUsMeter_done(Meter* this);
+
 static void CPUMeterCommonInit(Meter* this, int ncol) {
-   unsigned int cpus = this->pl->existingCPUs;
+   unsigned int cpus = this->pl->settings->showOnlyActiveCPUs ? this->pl->activeCPUs : this->pl->existingCPUs;
    CPUMeterData* data = this->meterData;
-   if (!data) {
+   if (!data || data->cpus != cpus) {
+      if (data)
+         AllCPUsMeter_done(this);
+
       data = this->meterData = xMalloc(sizeof(CPUMeterData));
       data->cpus = cpus;
       data->meters = xCalloc(cpus, sizeof(Meter*));
+      if (this->pl->settings->showOnlyActiveCPUs && (Meter_name(this)[0] == 'L' || Meter_name(this)[0] == 'R')) {
+         /* If there are more inactive CPUs in the first half then there are in the second half,
+          * shift the second half to begin at a later ID to cover the last CPU if online. */
+         unsigned int countL = 0, countR = 0;
+         for (unsigned int i = 0; i < this->pl->existingCPUs / 2; i++)
+            countL += ProcessList_isCPUonline(this->pl, i) ? 1 : 0;
+         for (unsigned int i = this->pl->existingCPUs / 2; i < this->pl->existingCPUs; i++)
+            countR += ProcessList_isCPUonline(this->pl, i) ? 1 : 0;
+         data->adjustActive = countR > countL ? countR - countL : 0;
+      } else
+         data->adjustActive = 0;
    }
+
    Meter** meters = data->meters;
    int start, count;
    AllCPUsMeter_getRange(this, &start, &count);
-   for (int i = 0; i < count; i++) {
+
+   int i = 0;
+
+   for (unsigned int j = start; j < this->pl->existingCPUs && i < count; j++) {
+      if (this->pl->settings->showOnlyActiveCPUs && !ProcessList_isCPUonline(this->pl, j))
+         continue;
+
+      if (!meters[i])
+         meters[i] = Meter_new(this->pl, j + 1, (const MeterClass*) Class(CPUMeter));
+
+      Meter_init(meters[i]);
+
+      i++;
+   }
+
+   /* Initialize any remaining items to the first CPU (there should however be none). */
+   assert(i == count);
+   for (; i < count; i++) {
       if (!meters[i])
-         meters[i] = Meter_new(this->pl, start + i + 1, (const MeterClass*) Class(CPUMeter));
+         meters[i] = Meter_new(this->pl, 1, (const MeterClass*) Class(CPUMeter));
 
       Meter_init(meters[i]);
    }

DisplayOptionsPanel.c

@@ -115,6 +115,7 @@ DisplayOptionsPanel* DisplayOptionsPanel_new(Settings* settings, ScreenManager*
    Panel_add(super, (Object*) CheckItem_newByRef("Leave a margin around header", &(settings->headerMargin)));
    Panel_add(super, (Object*) CheckItem_newByRef("Detailed CPU time (System/IO-Wait/Hard-IRQ/Soft-IRQ/Steal/Guest)", &(settings->detailedCPUTime)));
    Panel_add(super, (Object*) CheckItem_newByRef("Count CPUs from 1 instead of 0", &(settings->countCPUsFromOne)));
+   Panel_add(super, (Object*) CheckItem_newByRef("Show only active CPUs", &(settings->showOnlyActiveCPUs)));
    Panel_add(super, (Object*) CheckItem_newByRef("Update process names on every refresh", &(settings->updateProcessNames)));
    Panel_add(super, (Object*) CheckItem_newByRef("Add guest time in CPU meter percentage", &(settings->accountGuestInCPUMeter)));
    Panel_add(super, (Object*) CheckItem_newByRef("Also show CPU percentage numerically", &(settings->showCPUUsage)));

Settings.c

@@ -225,6 +225,8 @@ static bool Settings_read(Settings* this, const char* fileName, unsigned int ini
       } else if (String_eq(option[0], "cpu_count_from_zero")) {
          // old (inverted) naming also supported for backwards compatibility
          this->countCPUsFromOne = !atoi(option[1]);
+      } else if (String_eq(option[0], "show_only_active_cpu")) {
+         this->showOnlyActiveCPUs = atoi(option[1]);
       } else if (String_eq(option[0], "show_cpu_usage")) {
          this->showCPUUsage = atoi(option[1]);
       } else if (String_eq(option[0], "show_cpu_frequency")) {
@@ -352,6 +354,7 @@ int Settings_write(const Settings* this, bool onCrash) {
    fprintf(fd, "header_margin=%d\n", (int) this->headerMargin);
    fprintf(fd, "detailed_cpu_time=%d\n", (int) this->detailedCPUTime);
    fprintf(fd, "cpu_count_from_one=%d\n", (int) this->countCPUsFromOne);
+   fprintf(fd, "show_only_active_cpu=%d\n", (int) this->showOnlyActiveCPUs);
    fprintf(fd, "show_cpu_usage=%d\n", (int) this->showCPUUsage);
    fprintf(fd, "show_cpu_frequency=%d\n", (int) this->showCPUFrequency);
    #ifdef BUILD_WITH_CPU_TEMP
@@ -407,6 +410,7 @@ Settings* Settings_new(unsigned int initialCpuCount, Hashtable* dynamicColumns)
    this->highlightMegabytes = true;
    this->detailedCPUTime = false;
    this->countCPUsFromOne = false;
+   this->showOnlyActiveCPUs = false;
    this->showCPUUsage = true;
    this->showCPUFrequency = false;
    #ifdef BUILD_WITH_CPU_TEMP

Settings.h

@@ -40,6 +40,7 @@ typedef struct Settings_ {
    ProcessField treeSortKey;
 
    bool countCPUsFromOne;
+   bool showOnlyActiveCPUs;
    bool detailedCPUTime;
    bool showCPUUsage;
    bool showCPUFrequency;