Performance improvement hackathon: improve process comparison routines,

disable useless code in release builds such as runtime type-checking on
dynamic data structures and process fields that are not being computed,
faster(?) method for verifying the process owner (still need to ensure
correctness), don't destroy and create process objects for hidden kernel
threads over and over. Phew. I shouldn't be doing all this today, but I
could not resist.

ChangeLog

 
 What's new in version 0.6.3
 
+* Performance improvements; uses much less CPU than the
+  previous release with the default setup.
 * Use 64-bit values when storing processor times to
   avoid overflow.
+* Memory consumption improvements, compensating storage
+  of 64-bit values.
 * Internal change: rename TypedVector to Vector and
   ListBox (and related classes) to Panel.
 

CheckItem.c

@@ -21,11 +21,15 @@ typedef struct CheckItem_ {
 
 }*/
 
+#ifdef DEBUG
 char* CHECKITEM_CLASS = "CheckItem";
+#else
+#define CHECKITEM_CLASS NULL
+#endif
 
 CheckItem* CheckItem_new(char* text, bool* value) {
    CheckItem* this = malloc(sizeof(CheckItem));
-   ((Object*)this)->class = CHECKITEM_CLASS;
+   Object_setClass(this, CHECKITEM_CLASS);
    ((Object*)this)->display = CheckItem_display;
    ((Object*)this)->delete = CheckItem_delete;
    this->text = text;

CheckItem.h

@@ -22,7 +22,11 @@ typedef struct CheckItem_ {
 } CheckItem;
 
 
+#ifdef DEBUG
 extern char* CHECKITEM_CLASS;
+#else
+#define CHECKITEM_CLASS NULL
+#endif
 
 CheckItem* CheckItem_new(char* text, bool* value);
 

FunctionBar.c

@@ -30,7 +30,11 @@ typedef struct FunctionBar_ {
 
 }*/
 
+#ifdef DEBUG
 char* FUNCTIONBAR_CLASS = "FunctionBar";
+#else
+#define FUNCTIONBAR_CLASS NULL
+#endif
 
 static char* FunctionBar_FKeys[10] = {"F1", "F2", "F3", "F4", "F5", "F6", "F7", "F8", "F9", "F10"};
 
@@ -40,7 +44,7 @@ static int FunctionBar_FEvents[10] = {KEY_F(1), KEY_F(2), KEY_F(3), KEY_F(4), KE
 
 FunctionBar* FunctionBar_new(int size, char** functions, char** keys, int* events) {
    FunctionBar* this = malloc(sizeof(FunctionBar));
-   ((Object*) this)->class = FUNCTIONBAR_CLASS;
+   Object_setClass(this, FUNCTIONBAR_CLASS);
    ((Object*) this)->delete = FunctionBar_delete;
    this->functions = functions;
    this->size = size;

FunctionBar.h

@@ -31,7 +31,11 @@ typedef struct FunctionBar_ {
 } FunctionBar;
 
 
+#ifdef DEBUG
 extern char* FUNCTIONBAR_CLASS;
+#else
+#define FUNCTIONBAR_CLASS NULL
+#endif
 
 FunctionBar* FunctionBar_new(int size, char** functions, char** keys, int* events);
 

Hashtable.c

@@ -55,7 +55,7 @@ Hashtable* Hashtable_new(int size, bool owner) {
 }
 
 int Hashtable_hashAlgorithm(Hashtable* this, int key) {
-   return (key % this->size);
+   return key % this->size;
 }
 
 void Hashtable_delete(Hashtable* this) {
@@ -116,17 +116,20 @@ void* Hashtable_remove(Hashtable* this, int key) {
       } else
          bucketPtr = &((*bucketPtr)->next);
 }
-
+//#include <stdio.h>
 inline void* Hashtable_get(Hashtable* this, int key) {
    int index = this->hashAlgorithm(this, key);
    HashtableItem* bucketPtr = this->buckets[index];
-   while (true)
+   // fprintf(stderr, "%d -> %d\n", key, index);
+   while (true) {
       if (bucketPtr == NULL) {
          return NULL;
       } else if (bucketPtr->key == key) {
          return bucketPtr->value;
       } else
          bucketPtr = bucketPtr->next;
+      // fprintf(stderr, "*\n");
+   }
 }
 
 void Hashtable_foreach(Hashtable* this, Hashtable_PairFunction f, void* userData) {

Hashtable.h

@@ -47,7 +47,7 @@ inline int Hashtable_size(Hashtable* this);
 void Hashtable_put(Hashtable* this, int key, void* value);
 
 void* Hashtable_remove(Hashtable* this, int key);
-
+//#include <stdio.h>
 inline void* Hashtable_get(Hashtable* this, int key);
 
 void Hashtable_foreach(Hashtable* this, Hashtable_PairFunction f, void* userData);

Header.c

@@ -35,8 +35,8 @@ typedef struct Header_ {
 
 Header* Header_new(ProcessList* pl) {
    Header* this = malloc(sizeof(Header));
-   this->leftMeters = Vector_new(METER_CLASS, true, DEFAULT_SIZE);
-   this->rightMeters = Vector_new(METER_CLASS, true, DEFAULT_SIZE);
+   this->leftMeters = Vector_new(METER_CLASS, true, DEFAULT_SIZE, NULL);
+   this->rightMeters = Vector_new(METER_CLASS, true, DEFAULT_SIZE, NULL);
    this->margin = true;
    this->pl = pl;
    return this;

ListItem.c

@@ -23,14 +23,17 @@ typedef struct ListItem_ {
 
 }*/
 
+#ifdef DEBUG
 char* LISTITEM_CLASS = "ListItem";
+#else
+#define LISTITEM_CLASS NULL
+#endif
 
 ListItem* ListItem_new(char* value, int key) {
    ListItem* this = malloc(sizeof(ListItem));
-   ((Object*)this)->class = LISTITEM_CLASS;
+   Object_setClass(this, LISTITEM_CLASS);
    ((Object*)this)->display = ListItem_display;
    ((Object*)this)->delete = ListItem_delete;
-   ((Object*)this)->compare = ListItem_compare;
    this->value = String_copy(value);
    this->key = key;
    return this;
@@ -62,7 +65,7 @@ const char* ListItem_getRef(ListItem* this) {
    return this->value;
 }
 
-int ListItem_compare(const Object* cast1, const Object* cast2) {
+int ListItem_compare(const void* cast1, const void* cast2) {
    ListItem* obj1 = (ListItem*) cast1;
    ListItem* obj2 = (ListItem*) cast2;
    return strcmp(obj1->value, obj2->value);

ListItem.h

@@ -24,7 +24,11 @@ typedef struct ListItem_ {
 } ListItem;
 
 
+#ifdef DEBUG
 extern char* LISTITEM_CLASS;
+#else
+#define LISTITEM_CLASS NULL
+#endif
 
 ListItem* ListItem_new(char* value, int key);
 
@@ -36,7 +40,7 @@ void ListItem_display(Object* cast, RichString* out);
 
 const char* ListItem_getRef(ListItem* this);
 
-int ListItem_compare(const Object* cast1, const Object* cast2);
+int ListItem_compare(const void* cast1, const void* cast2);
 
 
 #endif

Makefile.am

@@ -27,6 +27,9 @@ ColorsPanel.c ColorsPanel.h TraceScreen.c TraceScreen.h \
 AvailableColumnsPanel.c AvailableColumnsPanel.h ColumnsPanel.c \
 ColumnsPanel.h
 
+profile:
+	$(MAKE) all CFLAGS="-pg -O2"
+
 debug:
 	$(MAKE) all CFLAGS="-g -DDEBUG"
 

Meter.c

@@ -104,7 +104,11 @@ typedef enum {
 #define MAX(a,b) ((a)>(b)?(a):(b))
 #endif
 
+#ifdef DEBUG
 char* METER_CLASS = "Meter";
+#else
+#define METER_CLASS NULL
+#endif
 
 MeterType* Meter_types[] = {
    &CPUMeter,
@@ -162,6 +166,9 @@ static RichString Meter_stringBuffer;
 
 Meter* Meter_new(ProcessList* pl, int param, MeterType* type) {
    Meter* this = calloc(sizeof(Meter), 1);
+   Object_setClass(this, METER_CLASS);
+   ((Object*)this)->delete = Meter_delete;
+   ((Object*)this)->display = type->display;
    this->h = 1;
    this->type = type;
    this->param = param;
@@ -169,9 +176,6 @@ Meter* Meter_new(ProcessList* pl, int param, MeterType* type) {
    this->values = calloc(sizeof(double), type->items);
    this->total = type->total;
    this->caption = strdup(type->caption);
-   ((Object*)this)->delete = Meter_delete;
-   ((Object*)this)->class = METER_CLASS;
-   ((Object*)this)->display = type->display;
    Meter_setMode(this, type->mode);
    if (this->type->init)
       this->type->init(this);

Meter.h

@@ -96,6 +96,7 @@ typedef enum {
 #include "TasksMeter.h"
 #include "LoadAverageMeter.h"
 #include "UptimeMeter.h"
+#include "ClockMeter.h"
 
 #ifndef MIN
 #define MIN(a,b) ((a)<(b)?(a):(b))
@@ -104,7 +105,11 @@ typedef enum {
 #define MAX(a,b) ((a)>(b)?(a):(b))
 #endif
 
+#ifdef DEBUG
 extern char* METER_CLASS;
+#else
+#define METER_CLASS NULL
+#endif
 
 extern MeterType* Meter_types[];
 

Object.c

@@ -15,37 +15,37 @@ in the source distribution for its full text.
 #include "debug.h"
 
 /*{
+
+#ifndef DEBUG
+#define Object_setClass(obj, class)
+#endif
+
 typedef struct Object_ Object;
 
 typedef void(*Object_Display)(Object*, RichString*);
-typedef int(*Object_Compare)(const Object*, const Object*);
+typedef int(*Object_Compare)(const void*, const void*);
 typedef void(*Object_Delete)(Object*);
 
 struct Object_ {
+   #ifdef DEBUG
    char* class;
+   #endif
    Object_Display display;
-   Object_Compare compare;
    Object_Delete delete;
 };
 }*/
 
-static char* OBJECT_CLASS = "Object";
+#ifdef DEBUG
+char* OBJECT_CLASS = "Object";
 
-void Object_new() {
-   Object* this;
-   this = malloc(sizeof(Object));
-   this->class = OBJECT_CLASS;
-   this->display = Object_display;
-   this->compare = Object_compare;
-   this->delete = Object_delete;
-}
+#else
+#define OBJECT_CLASS NULL
+#endif
 
-bool Object_instanceOf(Object* this, char* class) {
-   return this->class == class;
-}
+#ifdef DEBUG
 
-void Object_delete(Object* this) {
-   free(this);
+void Object_setClass(void* this, char* class) {
+   ((Object*)this)->class = class;
 }
 
 void Object_display(Object* this, RichString* out) {
@@ -54,6 +54,4 @@ void Object_display(Object* this, RichString* out) {
    RichString_write(out, CRT_colors[DEFAULT_COLOR], objAddress);
 }
 
-int Object_compare(const Object* this, const Object* o) {
-   return (this - o);
-}
+#endif

Object.h

@@ -17,27 +17,38 @@ in the source distribution for its full text.
 
 #include "debug.h"
 
+
+#ifndef DEBUG
+#define Object_setClass(obj, class)
+#endif
+
 typedef struct Object_ Object;
 
 typedef void(*Object_Display)(Object*, RichString*);
-typedef int(*Object_Compare)(const Object*, const Object*);
+typedef int(*Object_Compare)(const void*, const void*);
 typedef void(*Object_Delete)(Object*);
 
 struct Object_ {
+   #ifdef DEBUG
    char* class;
+   #endif
    Object_Display display;
-   Object_Compare compare;
    Object_Delete delete;
 };
 
-void Object_new();
+#ifdef DEBUG
+extern char* OBJECT_CLASS;
 
-bool Object_instanceOf(Object* this, char* class);
+#else
+#define OBJECT_CLASS NULL
+#endif
+
+#ifdef DEBUG
 
-void Object_delete(Object* this);
+void Object_setClass(void* this, char* class);
 
 void Object_display(Object* this, RichString* out);
 
-int Object_compare(const Object* this, const Object* o);
+#endif
 
 #endif

Panel.c

@@ -10,6 +10,7 @@ in the source distribution for its full text.
 #include "Vector.h"
 #include "CRT.h"
 #include "RichString.h"
+#include "ListItem.h"
 
 #include <math.h>
 #include <stdbool.h>
@@ -54,12 +55,18 @@ struct Panel_ {
 #define MAX(a,b) ((a)>(b)?(a):(b))
 #endif
 
+#ifdef DEBUG
 char* PANEL_CLASS = "Panel";
+#else
+#define PANEL_CLASS NULL
+#endif
+
 
-Panel* Panel_new(int x, int y, int w, int h, char* type, bool owner) {
+Panel* Panel_new(int x, int y, int w, int h, char* type, bool owner, Object_Compare compare) {
    Panel* this;
    this = malloc(sizeof(Panel));
    Panel_init(this, x, y, w, h, type, owner);
+   this->items->compare = compare;
    return this;
 }
 
@@ -71,14 +78,14 @@ void Panel_delete(Object* cast) {
 
 void Panel_init(Panel* this, int x, int y, int w, int h, char* type, bool owner) {
    Object* super = (Object*) this;
-   super->class = PANEL_CLASS;
+   Object_setClass(this, PANEL_CLASS);
    super->delete = Panel_delete;
    this->x = x;
    this->y = y;
    this->w = w;
    this->h = h;
    this->eventHandler = NULL;
-   this->items = Vector_new(type, owner, DEFAULT_SIZE);
+   this->items = Vector_new(type, owner, DEFAULT_SIZE, ListItem_compare);
    this->scrollV = 0;
    this->scrollH = 0;
    this->selected = 0;

Panel.h

@@ -55,9 +55,14 @@ struct Panel_ {
 #define MAX(a,b) ((a)>(b)?(a):(b))
 #endif
 
+#ifdef DEBUG
 extern char* PANEL_CLASS;
+#else
+#define PANEL_CLASS NULL
+#endif
+
 
-Panel* Panel_new(int x, int y, int w, int h, char* type, bool owner);
+Panel* Panel_new(int x, int y, int w, int h, char* type, bool owner, Object_Compare compare);
 
 void Panel_delete(Object* cast);
 

Process.c

@@ -62,16 +62,19 @@ typedef struct Process_ {
    int tty_nr;
    int tpgid;
    unsigned long int flags;
+   #ifdef DEBUG
    unsigned long int minflt;
    unsigned long int cminflt;
    unsigned long int majflt;
    unsigned long int cmajflt;
+   #endif
    unsigned long int utime;
    unsigned long int stime;
    long int cutime;
    long int cstime;
    long int priority;
    long int nice;
+   #ifdef DEBUG
    long int itrealvalue;
    unsigned long int starttime;
    unsigned long int vsize;
@@ -89,6 +92,7 @@ typedef struct Process_ {
    unsigned long int wchan;
    unsigned long int nswap;
    unsigned long int cnswap;
+   #endif
    int exit_signal;
    int processor;
    int m_size;
@@ -106,7 +110,11 @@ typedef struct Process_ {
 
 }*/
 
+#ifdef DEBUG
 char* PROCESS_CLASS = "Process";
+#else
+#define PROCESS_CLASS NULL
+#endif
 
 char *Process_fieldNames[] = {
    "", "PID", "Command", "STATE", "PPID", "PGRP", "SESSION", "TTY_NR", "TPGID", "FLAGS", "MINFLT", "CMINFLT", "MAJFLT", "CMAJFLT", "UTIME", "STIME", "CUTIME", "CSTIME", "PRIORITY", "NICE", "ITREALVALUE", "STARTTIME", "VSIZE", "RSS", "RLIM", "STARTCODE", "ENDCODE", "STARTSTACK", "KSTKESP", "KSTKEIP", "SIGNAL", "BLOCKED", "SIGIGNORE", "SIGCATCH", "WCHAN", "NSWAP", "CNSWAP", "EXIT_SIGNAL",  "PROCESSOR", "M_SIZE", "M_RESIDENT", "M_SHARE", "M_TRS", "M_DRS", "M_LRS", "M_DT", "ST_UID", "PERCENT_CPU", "PERCENT_MEM", "USER", "TIME", "*** report bug! ***"
@@ -114,9 +122,8 @@ char *Process_fieldNames[] = {
 
 Process* Process_new(struct ProcessList_ *pl) {
    Process* this = malloc(sizeof(Process));
-   ((Object*)this)->class = PROCESS_CLASS;
+   Object_setClass(this, PROCESS_CLASS);
    ((Object*)this)->display = Process_display;
-   ((Object*)this)->compare = Process_compare;
    ((Object*)this)->delete = Process_delete;
    this->pl = pl;
    this->tag = false;
@@ -265,21 +272,21 @@ void Process_writeField(Process* this, RichString* str, ProcessField field) {
          for (int i = 0; i < 32; i++)
             if (this->indent & (1 << i))
                maxIndent = i+1;
-	 for (int i = 0; i < maxIndent - 1; i++) {
+          for (int i = 0; i < maxIndent - 1; i++) {
             if (this->indent & (1 << i))
                snprintf(buf, n, " |  ");
             else
                snprintf(buf, n, "    ");
             buf += 4;
             n -= 4;
-	 }
+         }
          if (this->pl->direction == 1)
             snprintf(buf, n, " `- ");
          else
             snprintf(buf, n, " ,- ");
          RichString_append(str, CRT_colors[PROCESS_TREE], buffer);
          Process_writeCommand(this, attr, str);
-	 return;
+         return;
       }
    }
    case STATE: {
@@ -345,44 +352,57 @@ void Process_writeField(Process* this, RichString* str, ProcessField field) {
    return;
 }
 
-int Process_compare(const Object* v1, const Object* v2) {
+int Process_pidCompare(const void* v1, const void* v2) {
    Process* p1 = (Process*)v1;
    Process* p2 = (Process*)v2;
-   int direction = p1->pl->direction;
-   switch (p1->pl->sortKey) {
+   return (p1->pid - p2->pid);
+}
+
+int Process_compare(const void* v1, const void* v2) {
+   Process *p1, *p2;
+   ProcessList *pl = ((Process*)v1)->pl;
+   if (pl->direction == 1) {
+      p1 = (Process*)v1;
+      p2 = (Process*)v2;
+   } else {
+      p2 = (Process*)v1;
+      p1 = (Process*)v2;
+   }
+   switch (pl->sortKey) {
    case PID:
-      return (p2->pid - p1->pid) * direction;
+      return (p1->pid - p2->pid);
    case PPID:
-      return (p2->ppid - p1->ppid) * direction;
+      return (p1->ppid - p2->ppid);
    case USER:
-      return strcmp(p2->user, p1->user) * direction;
+      return strcmp(p1->user, p2->user);
    case PRIORITY:
-      return (p2->priority - p1->priority) * direction;
+      return (p1->priority - p2->priority);
    case STATE:
-      return (p2->state - p1->state) * direction;
+      return (p1->state - p2->state);
    case NICE:
-      return (p2->nice - p1->nice) * direction;
+      return (p1->nice - p2->nice);
    case M_SIZE:
-      return (p1->m_size - p2->m_size) * direction;
+      return (p2->m_size - p1->m_size);
    case M_RESIDENT:
-      return (p1->m_resident - p2->m_resident) * direction;
+      return (p2->m_resident - p1->m_resident);
    case M_SHARE:
-      return (p1->m_share - p2->m_share) * direction;
+      return (p2->m_share - p1->m_share);
    case PERCENT_CPU:
-      return (p1->percent_cpu < p2->percent_cpu ? -1 : 1) * direction;
+      return (p2->percent_cpu > p1->percent_cpu ? 1 : -1);
    case PERCENT_MEM:
-      return (p1->percent_mem < p2->percent_mem ? -1 : 1) * direction;
+      return (p2->m_resident - p1->m_resident);
    case UTIME:
-      return (p1->utime - p2->utime) * direction;
+      return (p2->utime - p1->utime);
    case STIME:
-      return (p1->stime - p2->stime) * direction;
+      return (p2->stime - p1->stime);
    case TIME:
-      return ((p1->utime+p1->stime) - (p2->utime+p2->stime)) * direction;
+      return ((p2->utime+p2->stime) - (p1->utime+p1->stime));
    case COMM:
-      return strcmp(p2->comm, p1->comm) * direction;
+      return strcmp(p1->comm, p2->comm);
    default:
-      return (p2->pid - p1->pid) * direction;
+      return (p1->pid - p2->pid);
    }
+
 }
 
 char* Process_printField(ProcessField field) {

Process.h

@@ -64,16 +64,19 @@ typedef struct Process_ {
    int tty_nr;
    int tpgid;
    unsigned long int flags;
+   #ifdef DEBUG
    unsigned long int minflt;
    unsigned long int cminflt;
    unsigned long int majflt;
    unsigned long int cmajflt;
+   #endif
    unsigned long int utime;
    unsigned long int stime;
    long int cutime;
    long int cstime;
    long int priority;
    long int nice;
+   #ifdef DEBUG
    long int itrealvalue;
    unsigned long int starttime;
    unsigned long int vsize;
@@ -91,6 +94,7 @@ typedef struct Process_ {
    unsigned long int wchan;
    unsigned long int nswap;
    unsigned long int cnswap;
+   #endif
    int exit_signal;
    int processor;
    int m_size;
@@ -107,7 +111,11 @@ typedef struct Process_ {
 } Process;
 
 
+#ifdef DEBUG
 extern char* PROCESS_CLASS;
+#else
+#define PROCESS_CLASS NULL
+#endif
 
 extern char *Process_fieldNames[];
 
@@ -131,7 +139,9 @@ void Process_sendSignal(Process* this, int signal);
 
 void Process_writeField(Process* this, RichString* str, ProcessField field);
 
-int Process_compare(const Object* v1, const Object* v2);
+int Process_pidCompare(const void* v1, const void* v2);
+
+int Process_compare(const void* v1, const void* v2);
 
 char* Process_printField(ProcessField field);
 

ProcessList.c

@@ -15,6 +15,7 @@ in the source distribution for its full text.
 #include "Vector.h"
 #include "UsersTable.h"
 #include "Hashtable.h"
+#include "String.h"
 
 #include <sys/types.h>
 #include <sys/stat.h>
@@ -48,13 +49,17 @@ in the source distribution for its full text.
 #endif
 
 #ifndef MAX_READ
-#define MAX_READ 8192
+#define MAX_READ 2048
 #endif
 
 }*/
 
 /*{
 
+#ifdef DEBUG
+typedef int(*vxscanf)(void*, const char*, va_list);
+#endif
+
 typedef struct ProcessList_ {
    Vector* processes;
    Vector* processes2;
@@ -108,8 +113,6 @@ static ProcessField defaultHeaders[] = { PID, USER, PRIORITY, NICE, M_SIZE, M_RE
 
 #ifdef DEBUG
 
-typedef int(*vxscanf)(void*, const char*, va_list);
-
 #define ProcessList_read(this, buffer, format, ...) ProcessList_xread(this, (vxscanf) vsscanf, buffer, format, ## __VA_ARGS__ )
 #define ProcessList_fread(this, file, format, ...)  ProcessList_xread(this, (vxscanf) vfscanf, file, format, ## __VA_ARGS__ )
 
@@ -173,13 +176,13 @@ static inline int ProcessList_xread(ProcessList* this, vxscanf fn, void* buffer,
 ProcessList* ProcessList_new(UsersTable* usersTable) {
    ProcessList* this;
    this = malloc(sizeof(ProcessList));
-   this->processes = Vector_new(PROCESS_CLASS, true, DEFAULT_SIZE);
+   this->processes = Vector_new(PROCESS_CLASS, true, DEFAULT_SIZE, Process_compare);
    this->processTable = Hashtable_new(20, false);
    this->prototype = Process_new(this);
    this->usersTable = usersTable;
    
    /* tree-view auxiliary buffers */
-   this->processes2 = Vector_new(PROCESS_CLASS, true, DEFAULT_SIZE);
+   this->processes2 = Vector_new(PROCESS_CLASS, true, DEFAULT_SIZE, Process_compare);
    
    #ifdef DEBUG
    this->traceFile = fopen("/tmp/htop-proc-trace", "w");
@@ -286,11 +289,8 @@ void ProcessList_add(ProcessList* this, Process* p) {
 
 void ProcessList_remove(ProcessList* this, Process* p) {
    Hashtable_remove(this->processTable, p->pid);
-   ProcessField pf = this->sortKey;
-   this->sortKey = PID;
-   int index = Vector_indexOf(this->processes, p);
+   int index = Vector_indexOf(this->processes, p, Process_pidCompare);
    Vector_remove(this->processes, index);
-   this->sortKey = pf;
 }
 
 Process* ProcessList_get(ProcessList* this, int index) {
@@ -302,7 +302,7 @@ int ProcessList_size(ProcessList* this) {
 }
 
 static void ProcessList_buildTree(ProcessList* this, int pid, int level, int indent, int direction) {
-   Vector* children = Vector_new(PROCESS_CLASS, false, DEFAULT_SIZE);
+   Vector* children = Vector_new(PROCESS_CLASS, false, DEFAULT_SIZE, Process_compare);
 
    for (int i = 0; i < Vector_size(this->processes); i++) {
       Process* process = (Process*) (Vector_get(this->processes, i));
@@ -352,7 +352,7 @@ void ProcessList_sort(ProcessList* this) {
 
 static int ProcessList_readStatFile(ProcessList* this, Process *proc, FILE *f, char *command) {
    static char buf[MAX_READ];
-   long int zero;
+   unsigned long int zero;
 
    int size = fread(buf, 1, MAX_READ, f);
    if(!size) return 0;
@@ -370,6 +370,7 @@ static int ProcessList_readStatFile(ProcessList* this, Process *proc, FILE *f, c
    command[commsize] = '\0';
    location = end + 2;
    
+   #ifdef DEBUG
    int num = ProcessList_read(this, location, 
       "%c %d %d %d %d %d %lu %lu %lu %lu "
       "%lu %lu %lu %ld %ld %ld %ld %ld %ld "
@@ -377,14 +378,34 @@ static int ProcessList_readStatFile(ProcessList* this, Process *proc, FILE *f, c
       "%lu %lu %lu %lu %lu %lu %lu %lu "
       "%d %d",
       &proc->state, &proc->ppid, &proc->pgrp, &proc->session, &proc->tty_nr, 
-      &proc->tpgid, &proc->flags, &proc->minflt, &proc->cminflt, &proc->majflt, 
-      &proc->cmajflt, &proc->utime, &proc->stime, &proc->cutime, &proc->cstime, 
+      &proc->tpgid, &proc->flags,
+      &proc->minflt, &proc->cminflt, &proc->majflt, &proc->cmajflt,
+      &proc->utime, &proc->stime, &proc->cutime, &proc->cstime, 
       &proc->priority, &proc->nice, &zero, &proc->itrealvalue, 
       &proc->starttime, &proc->vsize, &proc->rss, &proc->rlim, 
       &proc->startcode, &proc->endcode, &proc->startstack, &proc->kstkesp, 
       &proc->kstkeip, &proc->signal, &proc->blocked, &proc->sigignore, 
       &proc->sigcatch, &proc->wchan, &proc->nswap, &proc->cnswap, 
       &proc->exit_signal, &proc->processor);
+   #else
+   long int uzero;
+   int num = ProcessList_read(this, location, 
+      "%c %d %d %d %d %d %lu %lu %lu %lu "
+      "%lu %lu %lu %ld %ld %ld %ld %ld %ld "
+      "%lu %lu %ld %lu %lu %lu %lu %lu "
+      "%lu %lu %lu %lu %lu %lu %lu %lu "
+      "%d %d",
+      &proc->state, &proc->ppid, &proc->pgrp, &proc->session, &proc->tty_nr, 
+      &proc->tpgid, &proc->flags,
+      &zero, &zero, &zero, &zero,
+      &proc->utime, &proc->stime, &proc->cutime, &proc->cstime, 
+      &proc->priority, &proc->nice, &uzero, &uzero, 
+      &zero, &zero, &uzero, &zero, 
+      &zero, &zero, &zero, &zero, 
+      &zero, &zero, &zero, &zero, 
+      &zero, &zero, &zero, &zero, 
+      &proc->exit_signal, &proc->processor);
+   #endif
    
    // This assert is always valid on 2.4, but reportedly not always valid on 2.6.
    // TODO: Check if the semantics of this field has changed.
@@ -397,14 +418,15 @@ static int ProcessList_readStatFile(ProcessList* this, Process *proc, FILE *f, c
 bool ProcessList_readStatusFile(ProcessList* this, Process* proc, char* dirname, char* name) {
    char statusfilename[MAX_NAME+1];
    statusfilename[MAX_NAME] = '\0';
+   /*
+   bool success = false;
+   char buffer[256];
+   buffer[255] = '\0';
    snprintf(statusfilename, MAX_NAME, "%s/%s/status", dirname, name);
    FILE* status = ProcessList_fopen(this, statusfilename, "r");
-   bool success = false;
    if (status) {
-      char buffer[1024];
-      buffer[1023] = '\0';
       while (!feof(status)) {
-         char* ok = fgets(buffer, 1023, status);
+         char* ok = fgets(buffer, 255, status);
          if (!ok)
             break;
          if (String_startsWith(buffer, "Uid:")) {
@@ -421,14 +443,18 @@ bool ProcessList_readStatusFile(ProcessList* this, Process* proc, char* dirname,
       fclose(status);
    }
    if (!success) {
-      snprintf(statusfilename, MAX_NAME, "%s/%s/stat", dirname, name);
+   */
+      snprintf(statusfilename, MAX_NAME, "%s/%s", dirname, name);
       struct stat sstat;
       int statok = stat(statusfilename, &sstat);
       if (statok == -1)
          return false;
       proc->st_uid = sstat.st_uid;
-   }
-   return success;
+      return true;
+   /*
+   } else
+      return true;
+   */
 }
 
 void ProcessList_processEntries(ProcessList* this, char* dirname, int parent, float period) {
@@ -469,25 +495,25 @@ void ProcessList_processEntries(ProcessList* this, char* dirname, int parent, fl
          char command[PROCESS_COMM_LEN + 1];
 
          Process* process;
+
          Process* existingProcess = (Process*) Hashtable_get(this->processTable, pid);
-         if (!existingProcess) {
-            process = Process_clone(prototype);
+         if (existingProcess) {
+            process = existingProcess;
+         } else {
+            process = prototype;
+            process->comm = NULL;
             process->pid = pid;
-            ProcessList_add(this, process);
             if (! ProcessList_readStatusFile(this, process, dirname, name))
                goto errorReadingProcess;
-         } else {
-            process = existingProcess;
+            char* username = UsersTable_getRef(this->usersTable, process->st_uid);
+            if (username) {
+               strncpy(process->user, username, PROCESS_USER_LEN);
+            } else {
+               snprintf(process->user, PROCESS_USER_LEN, "%d", process->st_uid);
+            }
          }
          process->updated = true;
 
-         char* username = UsersTable_getRef(this->usersTable, process->st_uid);
-         if (username) {
-            strncpy(process->user, username, PROCESS_USER_LEN);
-         } else {
-            snprintf(process->user, PROCESS_USER_LEN, "%d", process->st_uid);
-         }
-
          int lasttimes = (process->utime + process->stime);
 
          snprintf(statusfilename, MAX_NAME, "%s/%s/stat", dirname, name);
@@ -498,13 +524,30 @@ void ProcessList_processEntries(ProcessList* this, char* dirname, int parent, fl
 
          int success = ProcessList_readStatFile(this, process, status, command);
          fclose(status);
-         if(!success) {
+         if(!success)
             goto errorReadingProcess;
-         }
 
          process->percent_cpu = (process->utime + process->stime - lasttimes) / 
             period * 100.0;
 
+         snprintf(statusfilename, MAX_NAME, "%s/%s/statm", dirname, name);
+         status = ProcessList_fopen(this, statusfilename, "r");
+
+         if(!status) {
+            goto errorReadingProcess;
+         }
+         int num = ProcessList_fread(this, status, "%d %d %d %d %d %d %d",
+             &process->m_size, &process->m_resident, &process->m_share, 
+             &process->m_trs, &process->m_drs, &process->m_lrs, 
+             &process->m_dt);
+
+         fclose(status);
+         if(num != 7)
+            goto errorReadingProcess;
+
+         if (this->hideKernelThreads && process->m_size == 0)
+            goto errorReadingProcess;
+
          if(!existingProcess) {
             snprintf(statusfilename, MAX_NAME, "%s/%s/cmdline", dirname, name);
             status = ProcessList_fopen(this, statusfilename, "r");
@@ -524,21 +567,6 @@ void ProcessList_processEntries(ProcessList* this, char* dirname, int parent, fl
             fclose(status);
          }
 
-         snprintf(statusfilename, MAX_NAME, "%s/%s/statm", dirname, name);
-         status = ProcessList_fopen(this, statusfilename, "r");
-
-         if(!status) {
-            goto errorReadingProcess;
-         }
-         int num = ProcessList_fread(this, status, "%d %d %d %d %d %d %d",
-             &process->m_size, &process->m_resident, &process->m_share, 
-             &process->m_trs, &process->m_drs, &process->m_lrs, 
-             &process->m_dt);
-
-         fclose(status);
-         if(num != 7)
-            goto errorReadingProcess;
-
          process->percent_mem = process->m_resident / 
             (float)(this->usedMem - this->cachedMem - this->buffersMem) * 
             100.0;
@@ -548,17 +576,25 @@ void ProcessList_processEntries(ProcessList* this, char* dirname, int parent, fl
             this->runningTasks++;
          }
 
-         if (this->hideKernelThreads && process->m_size == 0)
-            ProcessList_remove(this, process);
+         if (!existingProcess) {
+            process = Process_clone(process);
+            ProcessList_add(this, process);
+         }
 
          continue;
 
          // Exception handler.
          errorReadingProcess: {
-            ProcessList_remove(this, process);
+            if (existingProcess)
+               ProcessList_remove(this, process);
+            else {
+               if (process->comm)
+                  free(process->comm);
+            }
          }
       }
    }
+   prototype->comm = NULL;
    closedir(dir);
 }