From cb096c601d69ae83557cf707381c1c5aead04a6c Mon Sep 17 00:00:00 2001
From: Bill Currie <bill@taniwha.org>
Date: Mon, 18 Mar 2013 15:03:11 +0900
Subject: [PATCH] Use a per-portal rwlock for portal updates.

This should make qfvis scale a little better with cpu count.
---
 tools/qfvis/include/vis.h  |  6 ++++++
 tools/qfvis/source/flow.c  |  4 ++--
 tools/qfvis/source/qfvis.c | 26 ++++++++++++++++++--------
 3 files changed, 26 insertions(+), 10 deletions(-)

diff --git a/tools/qfvis/include/vis.h b/tools/qfvis/include/vis.h
index 75192b35a..92c304fb5 100644
--- a/tools/qfvis/include/vis.h
+++ b/tools/qfvis/include/vis.h
@@ -40,6 +40,7 @@
 #ifdef USE_PTHREADS
 #include <pthread.h>
 extern pthread_rwlock_t *global_lock;
+extern pthread_rwlock_t *portal_locks;
 
 #define	WRLOCK(l) \
 	do { \
@@ -58,6 +59,11 @@ extern pthread_rwlock_t *global_lock;
 		if (options.threads > 1)  \
 			pthread_rwlock_unlock (l); \
 	} while (0)
+
+#define WRLOCK_PORTAL(p) WRLOCK (&portal_locks[p - portals])
+#define RDLOCK_PORTAL(p) RDLOCK (&portal_locks[p - portals])
+#define UNLOCK_PORTAL(p) UNLOCK (&portal_locks[p - portals])
+
 #else
 #define	LOCK
 #define	UNLOCK
diff --git a/tools/qfvis/source/flow.c b/tools/qfvis/source/flow.c
index 2885a8e28..84edf205e 100644
--- a/tools/qfvis/source/flow.c
+++ b/tools/qfvis/source/flow.c
@@ -459,11 +459,11 @@ RecursiveClusterFlow (int clusternum, threaddata_t *thread, pstack_t *prevstack)
 void
 PortalFlow (threaddata_t *data, portal_t *portal)
 {
-	WRLOCK (global_lock);
+	WRLOCK_PORTAL (portal);
 	if (portal->status != stat_selected)
 		Sys_Error ("PortalFlow: reflowed");
 	portal->status = stat_working;
-	UNLOCK (global_lock);
+	UNLOCK_PORTAL (portal);
 
 	portal->visbits = set_new_size_r (&data->set_pool, portalclusters);
 
diff --git a/tools/qfvis/source/qfvis.c b/tools/qfvis/source/qfvis.c
index 733b597d6..a7e63e640 100644
--- a/tools/qfvis/source/qfvis.c
+++ b/tools/qfvis/source/qfvis.c
@@ -65,6 +65,7 @@
 #ifdef USE_PTHREADS
 pthread_attr_t threads_attrib;
 pthread_rwlock_t *global_lock;
+pthread_rwlock_t *portal_locks;
 pthread_rwlock_t *stats_lock;
 #endif
 
@@ -310,8 +311,10 @@ GetNextPortal (void)
 	}
 
 	if (p) {
+		WRLOCK_PORTAL (p);
 		portal_count++;
 		p->status = stat_selected;
+		UNLOCK_PORTAL (p);
 	}
 
 	UNLOCK (global_lock);
@@ -325,19 +328,19 @@ UpdateMightsee (cluster_t *source, cluster_t *dest)
 	int         i, clusternum;
 	portal_t   *portal;
 
-	WRLOCK (global_lock);
 	clusternum = dest - clusters;
 	for (i = 0; i < source->numportals; i++) {
 		portal = source->portals[i];
-		if (portal->status != stat_none)
-			continue;
-		if (set_is_member (portal->mightsee, clusternum)) {
-			set_remove (portal->mightsee, clusternum);
-			portal->nummightsee--;
-			stats.mightseeupdate++;
+		WRLOCK_PORTAL (portal);
+		if (portal->status == stat_none) {
+			if (set_is_member (portal->mightsee, clusternum)) {
+				set_remove (portal->mightsee, clusternum);
+				portal->nummightsee--;
+				stats.mightseeupdate++;
+			}
 		}
+		UNLOCK_PORTAL (portal);
 	}
-	UNLOCK (global_lock);
 }
 
 static void
@@ -888,6 +891,13 @@ LoadPortals (char *name)
 	// each file portal is split into two memory portals, one for each
 	// direction
 	portals = calloc (2 * numportals, sizeof (portal_t));
+#ifdef USE_PTHREADS
+	portal_locks = calloc (2 * numportals, sizeof (pthread_rwlock_t));
+	for (i = 0; i < 2 * numportals; i++) {
+		if (pthread_rwlock_init (&portal_locks[i], 0))
+			Sys_Error ("pthread_rwlock_init failed");
+	}
+#endif
 
 	clusters = calloc (portalclusters, sizeof (cluster_t));