VPP-1574: minimize RPC barrier sync calls
Grab the thread barrier across a set of RPCs, to greatly increase
efficiency. Avoids running afoul of the barrier sync holddown
timer.
Change-Id: I782dfdb1bed398b290169c83266681c9edd57a3f
Signed-off-by: Dave Barach <dave@barachs.net>
diff --git a/src/vlibmemory/memory_api.c b/src/vlibmemory/memory_api.c
index 1727c28..9fc26b9 100644
--- a/src/vlibmemory/memory_api.c
+++ b/src/vlibmemory/memory_api.c
@@ -735,11 +735,28 @@
vm->pending_rpc_requests = tmp;
clib_spinlock_unlock_if_init (&vm->pending_rpc_lock);
- for (i = 0; i < vec_len (vm->processing_rpc_requests); i++)
+ /*
+ * RPCs are used to reflect function calls to thread 0
+ * when the underlying code is not thread-safe.
+ *
+ * Grabbing the thread barrier across a set of RPCs
+ * greatly increases efficiency, and avoids
+ * running afoul of the barrier sync holddown timer.
+ * The barrier sync code supports recursive locking.
+ *
+ * We really need to rewrite RPC-based code...
+ */
+ if (PREDICT_TRUE (vec_len (vm->processing_rpc_requests)))
{
- mp = vm->processing_rpc_requests[i];
- vl_msg_api_handler_with_vm_node (am, (void *) mp, vm, node);
+ vl_msg_api_barrier_sync ();
+ for (i = 0; i < vec_len (vm->processing_rpc_requests); i++)
+ {
+ mp = vm->processing_rpc_requests[i];
+ vl_msg_api_handler_with_vm_node (am, (void *) mp, vm, node);
+ }
+ vl_msg_api_barrier_release ();
}
+
return 0;
}