* authorization. *
****************************************************************************/
/*
- * $Id: rain.c,v 1.26 2008/03/09 00:17:09 tom Exp $
+ * $Id: rain.c,v 1.34 2008/05/24 23:34:34 tom Exp $
*/
#include <test.priv.h>
WANT_USE_WINDOW();
-#define MAX_DROP 5
+#define MAX_THREADS 10
+#define MAX_DROP 5
struct DATA;
typedef struct DATA {
int y, x;
#ifdef USE_PTHREADS
- pthread_t thread;
DrawPart func;
int state;
#endif
} DATA;
+#ifdef USE_PTHREADS
+pthread_cond_t cond_next_drop;
+pthread_mutex_t mutex_next_drop;
+static int used_threads;
+
+typedef struct {
+ pthread_t myself;
+ long counter;
+} STATS;
+
+static STATS drop_threads[MAX_THREADS];
+#endif
+
static void
onsig(int n GCC_UNUSED)
{
static void
napsome(void)
{
- refresh();
napms(60);
}
/*
- * This runs inside the mutex.
+ * This runs inside the use_window() mutex.
*/
static int
really_draw(WINDOW *win, void *arg)
(void) win;
next_j(data->state);
data->func(data);
+ refresh();
return OK;
}
napsome();
}
+/*
+ * Tell the threads that one of them can start work on a new raindrop.
+ * They may all be busy if we're sending requests too rapidly.
+ */
+static int
+put_next_drop(void)
+{
+ pthread_cond_signal(&cond_next_drop);
+ pthread_mutex_unlock(&mutex_next_drop);
+
+ return 0;
+}
+
+/*
+ * Wait until we're assigned the task of drawing a new raindrop.
+ */
+static int
+get_next_drop(void)
+{
+ pthread_mutex_lock(&mutex_next_drop);
+ pthread_cond_wait(&cond_next_drop, &mutex_next_drop);
+
+ return TRUE;
+}
+
static void *
draw_drop(void *arg)
{
DATA mydata;
+ int mystats;
+
+ /*
+ * Find myself in the list of threads so we can count the number of loops.
+ */
+ for (mystats = 0; mystats < MAX_THREADS; ++mystats) {
+ if (drop_threads[mystats].myself == pthread_self())
+ break;
+ }
+
+ do {
+ if (mystats < MAX_THREADS)
+ drop_threads[mystats].counter++;
- mydata = *(DATA *) arg; /* make a copy of caller's data */
+ /*
+ * Make a copy of caller's data. We're cheating for the cases after
+ * the first loop since we still have a pointer into the main thread
+ * to the data which it uses for setting up this thread (but it has
+ * been modified to use different coordinates).
+ */
+ mydata = *(DATA *) arg;
- draw_part(part1, 0, &mydata);
- draw_part(part2, 1, &mydata);
- draw_part(part3, 2, &mydata);
- draw_part(part4, 3, &mydata);
- draw_part(part5, 4, &mydata);
- draw_part(part6, 0, &mydata);
+ draw_part(part1, 0, &mydata);
+ draw_part(part2, 1, &mydata);
+ draw_part(part3, 2, &mydata);
+ draw_part(part4, 3, &mydata);
+ draw_part(part5, 4, &mydata);
+ draw_part(part6, 0, &mydata);
+ } while (get_next_drop());
return NULL;
}
+
+/*
+ * The description of pthread_create() is misleading, since it implies that
+ * threads will exit cleanly after their function returns.
+ *
+ * Since they do not (and the number of threads is limited by system
+ * resources), make a limited number of threads, and signal any that are
+ * waiting when we want a thread past that limit.
+ */
+static int
+start_drop(DATA * data)
+{
+ int rc;
+
+ if (!used_threads) {
+ /* mutex and condition for signalling thread */
+ pthread_mutex_init(&mutex_next_drop, NULL);
+ pthread_cond_init(&cond_next_drop, NULL);
+ }
+
+ if (used_threads < MAX_THREADS) {
+ rc = pthread_create(&(drop_threads[used_threads].myself),
+ NULL,
+ draw_drop,
+ data);
+ ++used_threads;
+ } else {
+ rc = put_next_drop();
+ }
+ return rc;
+}
#endif
static int
get_input(void)
{
- int ch;
- ch = USING_WINDOW(stdscr, wgetch);
- return ch;
+ return USING_WINDOW(stdscr, wgetch);
}
int
main(int argc GCC_UNUSED,
char *argv[]GCC_UNUSED)
{
+ bool done = FALSE;
DATA drop;
+#ifndef USE_PTHREADS
DATA last[MAX_DROP];
+#endif
int j = 0;
- bool done = FALSE;
setlocale(LC_ALL, "");
curs_set(0);
timeout(0);
+#ifndef USE_PTHREADS
for (j = MAX_DROP; --j >= 0;) {
last[j].x = random_x();
last[j].y = random_y();
}
+ j = 0;
+#endif
while (!done) {
drop.x = random_x();
drop.y = random_y();
#ifdef USE_PTHREADS
- if (pthread_create(&(drop.thread), NULL, draw_drop, &drop)) {
+ if (start_drop(&drop) != 0) {
beep();
- done = TRUE;
- continue;
}
#else
/*
}
curs_set(1);
endwin();
+#ifdef USE_PTHREADS
+ printf("Counts per thread:\n");
+ for (j = 0; j < MAX_THREADS; ++j)
+ printf(" %d:%ld\n", j, drop_threads[j].counter);
+#endif
ExitProgram(EXIT_SUCCESS);
}