From 4710dbeef96a84c81c1b11e0b5164f9918b64cd4 Mon Sep 17 00:00:00 2001
From: Randy McShandy <randy@mcshandy.xyz>
Date: Tue, 12 Dec 2023 22:38:39 -0600
Subject: [PATCH] threading rework and it seems to be working, with actual
 speedups

---
 main.c | 97 +++++++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 92 insertions(+), 5 deletions(-)

diff --git a/main.c b/main.c
index 057f71d..574da26 100755
--- a/main.c
+++ b/main.c
@@ -57,6 +57,7 @@ typedef struct
 
 	int* waiting_workers;
 	int worker_count;
+	int iterations;
 	int max_iterations;
 	int worker_id;
 } worker_arg;
@@ -180,6 +181,75 @@ float rd_b_prime(FVec2** source_grid, RD_Opts opts, int x, int y, Mat3 kernel, f
 }
 
 void* iterator(void* _arg)
+{
+	worker_arg* warg = (worker_arg*)_arg;
+	RD_Opts opts = warg->opts;
+	int start_x = warg->start_x;
+	int start_y = warg->start_y;
+	int w = warg->width;//(warg->width + start_x >= GRID_X) ? GRID_X-1 - start_x: warg->width;
+	int h = warg->height;//(warg->height + start_y >= GRID_Y) ? GRID_Y-1 - start_y : warg->height;
+
+	for (warg->iterations = 0; warg->iterations < warg->max_iterations; warg->iterations++)
+	{
+		printf("worker %d: work unit %d/%d\n", warg->worker_id, warg->iterations, warg->max_iterations);
+		for (int x = start_x; x < w + start_x; x++)
+		{
+			for (int y = start_y; y < h + start_y; y++)
+			{
+				FVec2 each = grid[x][y];
+				grid_prime[x][y].a = rd_a_prime(grid, opts, x, y, laplacian_kernel, each.a, each.b);
+				grid_prime[x][y].b = rd_b_prime(grid, opts, x, y, laplacian_kernel, each.a, each.b);
+			}
+		}
+
+#if 1
+		// Last one done should wake up the boss thread
+		int last_worker = 0;
+		pthread_mutex_lock(warg->mutex);
+		if (++*warg->waiting_workers == warg->worker_count)
+		{
+			last_worker = 1;
+		}
+		pthread_mutex_unlock(warg->mutex);
+
+		if (last_worker == 0)
+		{
+			pthread_cond_wait(warg->worker_cond, &warg->worker_mutex);
+		}
+		else
+		{
+			grid_temp = grid;
+			grid = grid_prime;
+			grid_prime = grid_temp;
+
+			// segfault somewhere in here lmao
+			if (1 && (warg->iterations % 100 == 0))
+			{
+				char buffer[GRID_X][GRID_Y];
+				for (int x = 0; x < GRID_X; x++)
+				{
+					for (int y = 0; y < GRID_Y; y++)
+					{
+						buffer[x][y] = (uint8_t)(255.0f * grid[x][y].a);
+					}
+				}
+				char name[64] = {0};
+				sprintf(name, "img/%s/%d.png", opts.name, warg->iterations);
+				stbi_write_png(name, GRID_X, GRID_Y, 1, buffer, GRID_X * sizeof(uint8_t));
+			}
+			printf("worker-boss %d: completing report\n", warg->worker_id);
+
+			*warg->waiting_workers = 0;
+			pthread_cond_broadcast(warg->worker_cond);
+		}
+#endif
+	}
+
+	printf("worker %d: exiting\n", warg->worker_id);
+	return _arg;
+}
+
+void* iterator_old(void* _arg)
 {
 	worker_arg* warg = (worker_arg*)_arg;
 	RD_Opts opts = warg->opts;
@@ -201,9 +271,15 @@ void* iterator(void* _arg)
 			}
 		}
 
+		// Last one done should wake up the boss thread
+		pthread_mutex_lock(warg->mutex);
 		++*warg->waiting_workers;
-		printf("worker %d: waking up boss\n", warg->worker_id);
-		pthread_cond_signal(warg->boss_cond);
+		if (*warg->waiting_workers == warg->worker_count)
+		{
+			printf("worker %d: waking up boss\n", warg->worker_id);
+			pthread_cond_signal(warg->boss_cond);
+		}
+		pthread_mutex_unlock(warg->mutex);
 
 		pthread_cond_wait(warg->worker_cond, &warg->worker_mutex);
 
@@ -272,7 +348,7 @@ int main(int argc, char** argv)
 	{
 		wargs[t]						= warg;
 		wargs[t].worker_id	= t;
-		wargs[t].width			= (GRID_X/warg.worker_count);
+		wargs[t].width			= (GRID_X/warg.worker_count) + ((t == warg.worker_count-1) ? 0 : 4);
 		wargs[t].start_x		= (wargs[t].width * t);
 		pthread_mutex_init(&wargs[t].worker_mutex, NULL);
 		printf("worker %d x_span %d, %d\n", t, wargs[t].start_x, wargs[t].width);
@@ -281,13 +357,16 @@ int main(int argc, char** argv)
 
 	int max_iterations = (GRID_X / 128.0f) * opts.max_iterations;
 	max_iterations = warg.max_iterations;
+	/*
 	for (int iterations = 0; iterations < max_iterations; iterations++)
 	{
 		printf("boss: waiting on workers\n");
+		pthread_mutex_lock(warg.mutex);
 		while (*warg.waiting_workers < warg.worker_count)
 		{
 			pthread_cond_wait(warg.boss_cond, warg.mutex);
 		}
+		pthread_mutex_unlock(warg.mutex);
 
 		grid_temp = grid;
 		grid = grid_prime;
@@ -311,8 +390,16 @@ int main(int argc, char** argv)
 				 }
 		}
 
-		*warg.waiting_workers = 0;
-		pthread_cond_broadcast(warg.worker_cond);
+	}
+	*/
+
+	int should_quit = 0;
+	while(!should_quit)
+	{
+		pthread_mutex_lock(warg.mutex);
+			if (wargs[0].iterations == wargs[0].max_iterations-1)
+				should_quit = 1;
+		pthread_mutex_unlock(warg.mutex);
 	}
 
 	printf("boss: exiting loop\n");
-- 
2.49.0