From: Randy McShandy <randy@mcshandy.xyz>
Date: Wed, 13 Dec 2023 06:06:25 +0000 (-0600)
Subject: HEY WHO THE FUCK DIDN'T TELL ME ABOUT PTHREAD BARRIERS
X-Git-Url: http://git.mcshandy.xyz/gitweb.cgi?a=commitdiff_plain;h=b4c6cc6905bafa6a4c31c0850bf044ca882adc70;p=barrow_crawler

HEY WHO THE FUCK DIDN'T TELL ME ABOUT PTHREAD BARRIERS
---

diff --git a/main.c b/main.c
index 1fc6dca..d232420 100755
--- a/main.c
+++ b/main.c
@@ -8,7 +8,7 @@
 #define STB_IMAGE_WRITE_IMPLEMENTATION
 #include "stb_image_write.h"
 
-#define GRID_X 128
+#define GRID_X 512
 #define GRID_Y GRID_X
 
 #define SHADOW 0
@@ -54,6 +54,7 @@ typedef struct
 	pthread_mutex_t		worker_mutex;
 	pthread_cond_t*		worker_cond;
 	pthread_cond_t*		boss_cond;
+	pthread_barrier_t* barrier;
 
 	int* waiting_workers;
 	int worker_count;
@@ -186,8 +187,8 @@ void* iterator(void* _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;
+	int w = warg->width;
+	int h = warg->height;
 
 	for (warg->iterations = 0; warg->iterations < warg->max_iterations; warg->iterations++)
 	{
@@ -202,7 +203,34 @@ void* iterator(void* _arg)
 			}
 		}
 
-#if 1
+		pthread_mutex_lock(warg->mutex);
+		if (++*warg->waiting_workers == warg->worker_count)
+		{
+			grid_temp = grid;
+			grid = grid_prime;
+			grid_prime = grid_temp;
+			*warg->waiting_workers = 0;
+			printf("worker-boss %d: completing report\n", warg->worker_id);
+			if ((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));
+			}
+		}
+		pthread_mutex_unlock(warg->mutex);
+
+		pthread_barrier_wait(warg->barrier);
+
+#if 0
 		// Last one done should wake up the boss thread
 		int last_worker = 0;
 		pthread_mutex_lock(warg->mutex);
@@ -223,7 +251,7 @@ void* iterator(void* _arg)
 			grid_prime = grid_temp;
 
 			// segfault somewhere in here lmao
-			if (1 && (warg->iterations % 100 == 0))
+			if ((warg->iterations % 100 == 0))
 			{
 				char buffer[GRID_X][GRID_Y];
 				for (int x = 0; x < GRID_X; x++)
@@ -327,20 +355,23 @@ int main(int argc, char** argv)
 
 	int waiting_workers = 0;
 	worker_arg warg = {
-		opts, grid, grid_prime, 0, 0, (GRID_X), (GRID_Y), .worker_count = 4, .waiting_workers = &waiting_workers, .max_iterations = 1e4
+		opts, grid, grid_prime, 0, 0, (GRID_X), (GRID_Y), .worker_count = 8, .waiting_workers = &waiting_workers, .max_iterations = 1e4,
 	};
 	pthread_t threads[warg.worker_count];
 	pthread_mutex_t mutex;
 	pthread_cond_t worker_cond;
 	pthread_cond_t boss_cond;
+	pthread_barrier_t barrier;
 
 	pthread_mutex_init(&mutex, NULL);
 	pthread_cond_init(&worker_cond, NULL);
 	pthread_cond_init(&boss_cond, NULL);
+	pthread_barrier_init(&barrier, NULL, warg.worker_count);
 
 	warg.worker_cond	= &worker_cond;
 	warg.boss_cond		= &boss_cond;
 	warg.mutex				= &mutex;
+	warg.barrier			= &barrier;
 
 	worker_arg wargs[warg.worker_count];