path: root/
diff options
authorwm4 <wm4@nowhere>2014-07-26 20:29:48 +0200
committerwm4 <wm4@nowhere>2014-07-26 20:29:48 +0200
commit559fe1daace8f48a8dc37906f840e9981b961415 (patch)
tree35f892f0126dc112c2af36080b0a0a5e1d70b597 /
parent8ed6d298c5dba49bd4f1e5dc877fcd67652123b2 (diff)
Add Plan 9-style barriers
Plan 9 has a very interesting synchronization mechanism, the rendezvous() call. A good property of this is that you don't need to explicitly initialize and destroy a barrier object, unlike as with e.g. POSIX barriers (which are mandatory to begin with). Upon "meeting", they can exchange a value. This mechanism will be nice to synchronize certain stages of initialization between threads in the following commit. Unlike Plan 9 rendezvous(), this is not implemented with a hashtable, because that would require additional effort (especially if you want to make it actually scele). Unlike the Plan 9 variant, we use intptr_t instead of void* as type for the value, because I expect that we will be mostly passing a status code as value and not a pointer. Converting an integer to void* requires two cast (because the integer needs to be intptr_t), the other way around it's only one cast. We don't particularly care about performance in this case either. It's simply not important for our use-case. So a simple linked list is used for waiters, and on wakeup, all waiters are temporarily woken up.
Diffstat (limited to '')
1 files changed, 1 insertions, 0 deletions
diff --git a/ b/
index 62446d1907..463c3c1084 100644
--- a/
+++ b/
@@ -201,6 +201,7 @@ def build(ctx):
( "misc/charset_conv.c" ),
( "misc/dispatch.c" ),
( "misc/ring.c" ),
+ ( "misc/rendezvous.c" ),
## Options
( "options/m_config.c" ),