With the help of stack overflow, I have built GTK3 application with threads. It works fine. But it uses about 90% of CPU load. Could you advise me what causes this problem? It doesn't help even I increase the sleep time from 100 ms to 1 sec.
The code is here: https://gist.github.com/ymkim92/247b801a003efbb274e68297a12951a5
// gcc ledgui.c `pkg-config --cflags gtk+-3.0 pkg-config --libs gtk+-3.0`
// It will have very high CPU load when you run this code.
// You can find the fixed version of this code at here:
// https://stackoverflow.com/questions/64019411/very-high-cpu-load-when-i-run-my-own-simple-gtk-application
#include <gtk/gtk.h>
#include <string.h>
#include <stdlib.h>
#define LED_COLOR_RED 0
#define LED_COLOR_GREEN 1
#define LED_COLOR_YELLOW 2
#define LED_COLOR_OFF 3
#define LED_COLOR_COUNT 4
char *color[] = {"red", "green", "yellow", "black"};
GtkWidget *ledLight;
GMutex mutex;
gchar ledText[256];
void *LedTask1 (void *vargp);
void *LedTask2 (void *vargp);
void LedGuiThread ();
void SetFontColors(GtkWidget *grid);
gboolean updateLabel(gpointer data);
void Task_sleep_ms(int ms);
void SetTextColor(char* fcolor);
int main()
{
pthread_t thread_id;
pthread_t thread_id2;
LedGuiThread();
pthread_create(&thread_id2, NULL, LedTask1, NULL);
pthread_create(&thread_id, NULL, LedTask2, NULL);
gtk_main();
// pthread_join(thread_id2, NULL);
// pthread_join(thread_id, NULL);
exit(0);
}
void *LedTask1 (void *vargp)
{
while (1)
{
Task_sleep_ms(100);
SetTextColor(color[LED_COLOR_RED]);
g_idle_add(updateLabel, ledLight);
Task_sleep_ms(100);
SetTextColor(color[LED_COLOR_OFF]);
g_idle_add(updateLabel, ledLight);
}
}
void *LedTask2 (void *vargp)
{
while (1)
{
Task_sleep_ms(100);
SetTextColor(color[LED_COLOR_GREEN]);
g_idle_add(updateLabel, ledLight);
Task_sleep_ms(100);
SetTextColor(color[LED_COLOR_OFF]);
g_idle_add(updateLabel, ledLight);
}
}
void LedGuiThread()
{
GtkWidget *window;
GtkWidget *grid;
GtkWidget *ledLabel;
int argc=0;
char **argv=NULL;
gtk_init (&argc,&argv);
//Declarations
window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
gtk_window_set_title(GTK_WINDOW(window), "LED");
grid = gtk_grid_new ();
SetFontColors(grid);
ledLabel = gtk_label_new ("1");
ledLight = gtk_label_new ("O");
//Set Properties
gtk_container_set_border_width (GTK_CONTAINER(window), 20);
gtk_widget_set_size_request (GTK_WIDGET(window), 200, 50);
gtk_grid_set_row_spacing (GTK_GRID(grid), 4);
gtk_grid_set_column_spacing (GTK_GRID(grid), 4);
gtk_container_add (GTK_CONTAINER(window), grid);
//Fill the grid with shit (x, y, h, v)
gtk_grid_attach (GTK_GRID(grid), ledLabel, 2, 2, 2, 1);
gtk_grid_attach (GTK_GRID(grid), ledLight, 2, 3, 2, 1);
gtk_widget_show_all (window);
g_signal_connect(G_OBJECT(window), "destroy", G_CALLBACK(gtk_main_quit), NULL);
}
void SetFontColors(GtkWidget *grid)
{
GtkCssProvider *provider;
GtkStyleContext *context;
/* Change default font and color throughout the widget */
provider = gtk_css_provider_new();
gtk_css_provider_load_from_data(provider,
"* {"
" color: white;"
" background-color: black;"
" font: 20px monospace;"
"}",
-1,
NULL);
context = gtk_widget_get_style_context(grid);
gtk_style_context_add_provider(context,
GTK_STYLE_PROVIDER(provider),
GTK_STYLE_PROVIDER_PRIORITY_APPLICATION);
}
gboolean updateLabel(gpointer data)
{
char text[256];
GtkLabel *led = data;
g_mutex_lock (&mutex);
strncpy(text, ledText, sizeof(text));
g_mutex_unlock (&mutex);
gtk_label_set_markup (GTK_LABEL (led), text);
}
void Task_sleep_ms(int ms)
{
// printf("sleep %d ms\n", ms);
usleep(ms * 1000);
}
void SetTextColor(char* fcolor)
{
g_mutex_lock(&mutex);
snprintf(ledText, 256, "<span background=\"black\" foreground=\"%s\">O</span>", fcolor);
g_mutex_unlock(&mutex);
}
Thanks Dan, I have just added return FALSE; at the end of updateLabel function. It uses less than 1% of CPU load now.
// gcc ledgui.c `pkg-config --cflags gtk+-3.0 pkg-config --libs gtk+-3.0`
#include <gtk/gtk.h>
#include <string.h>
#include <stdlib.h>
#define LED_COLOR_RED 0
#define LED_COLOR_GREEN 1
#define LED_COLOR_YELLOW 2
#define LED_COLOR_OFF 3
#define LED_COLOR_COUNT 4
char *color[] = {"red", "green", "yellow", "black"};
GtkWidget *ledLight;
GMutex mutex;
gchar ledText[256];
void *LedTask1 (void *vargp);
void *LedTask2 (void *vargp);
void LedGuiThread ();
void SetFontColors(GtkWidget *grid);
gboolean updateLabel(gpointer data);
void Task_sleep_ms(int ms);
void SetTextColor(char* fcolor);
int main()
{
pthread_t thread_id;
pthread_t thread_id2;
LedGuiThread();
pthread_create(&thread_id2, NULL, LedTask1, NULL);
pthread_create(&thread_id, NULL, LedTask2, NULL);
gtk_main();
// pthread_join(thread_id2, NULL);
// pthread_join(thread_id, NULL);
exit(0);
}
void *LedTask1 (void *vargp)
{
while (1)
{
Task_sleep_ms(100);
SetTextColor(color[LED_COLOR_RED]);
g_idle_add(updateLabel, ledLight);
Task_sleep_ms(100);
SetTextColor(color[LED_COLOR_OFF]);
g_idle_add(updateLabel, ledLight);
}
}
void *LedTask2 (void *vargp)
{
while (1)
{
Task_sleep_ms(100);
SetTextColor(color[LED_COLOR_GREEN]);
g_idle_add(updateLabel, ledLight);
Task_sleep_ms(100);
SetTextColor(color[LED_COLOR_OFF]);
g_idle_add(updateLabel, ledLight);
}
}
void LedGuiThread()
{
GtkWidget *window;
GtkWidget *grid;
GtkWidget *ledLabel;
int argc=0;
char **argv=NULL;
gtk_init (&argc,&argv);
//Declarations
window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
gtk_window_set_title(GTK_WINDOW(window), "LED");
grid = gtk_grid_new ();
SetFontColors(grid);
ledLabel = gtk_label_new ("1");
ledLight = gtk_label_new ("O");
//Set Properties
gtk_container_set_border_width (GTK_CONTAINER(window), 20);
gtk_widget_set_size_request (GTK_WIDGET(window), 200, 50);
gtk_grid_set_row_spacing (GTK_GRID(grid), 4);
gtk_grid_set_column_spacing (GTK_GRID(grid), 4);
gtk_container_add (GTK_CONTAINER(window), grid);
//Fill the grid with shit (x, y, h, v)
gtk_grid_attach (GTK_GRID(grid), ledLabel, 2, 2, 2, 1);
gtk_grid_attach (GTK_GRID(grid), ledLight, 2, 3, 2, 1);
gtk_widget_show_all (window);
g_signal_connect(G_OBJECT(window), "destroy", G_CALLBACK(gtk_main_quit), NULL);
}
void SetFontColors(GtkWidget *grid)
{
GtkCssProvider *provider;
GtkStyleContext *context;
/* Change default font and color throughout the widget */
provider = gtk_css_provider_new();
gtk_css_provider_load_from_data(provider,
"* {"
" color: white;"
" background-color: black;"
" font: 20px monospace;"
"}",
-1,
NULL);
context = gtk_widget_get_style_context(grid);
gtk_style_context_add_provider(context,
GTK_STYLE_PROVIDER(provider),
GTK_STYLE_PROVIDER_PRIORITY_APPLICATION);
}
gboolean updateLabel(gpointer data)
{
char text[256];
GtkLabel *led = data;
g_mutex_lock (&mutex);
strncpy(text, ledText, sizeof(text));
g_mutex_unlock (&mutex);
gtk_label_set_markup (GTK_LABEL (led), text);
// If the function returns FALSE
// it is automatically removed from the list
// of event sources and will not be called again.
return FALSE;
}
void Task_sleep_ms(int ms)
{
// printf("sleep %d ms\n", ms);
usleep(ms * 1000);
}
void SetTextColor(char* fcolor)
{
g_mutex_lock(&mutex);
snprintf(ledText, 256, "<span background=\"black\" foreground=\"%s\">O</span>", fcolor);
g_mutex_unlock(&mutex);
}