From f51d56c80c57855a01fb0e1a0fb58716b83de6c6 Mon Sep 17 00:00:00 2001
From: James Phillips <slackpad@gmail.com>
Date: Wed, 9 Aug 2017 18:51:55 -0700
Subject: [PATCH] Switches to using a read lock for the agent's RPC dispatcher.

This prevents RPC calls from getting serialized in this spot.

Fixes #3376
---
 CHANGELOG.md   | 2 ++
 agent/agent.go | 4 ++--
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index a7422ea74b..d898fa33b3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,8 @@ FEATURES:
 
 IMPROVEMENTS:
 
+* agent: Switched to using a read lock for the agent's RPC dispatcher, which prevents RPC calls from getting serialized. [GH-3376]
+
 BUG FIXES:
 
 ## 0.9.2 (August 9, 2017)
diff --git a/agent/agent.go b/agent/agent.go
index ecb7798f0f..652143ec54 100644
--- a/agent/agent.go
+++ b/agent/agent.go
@@ -956,7 +956,7 @@ func (a *Agent) registerEndpoint(name string, handler interface{}) error {
 // RPC is used to make an RPC call to the Consul servers
 // This allows the agent to implement the Consul.Interface
 func (a *Agent) RPC(method string, args interface{}, reply interface{}) error {
-	a.endpointsLock.Lock()
+	a.endpointsLock.RLock()
 	// fast path: only translate if there are overrides
 	if len(a.endpoints) > 0 {
 		p := strings.SplitN(method, ".", 2)
@@ -964,7 +964,7 @@ func (a *Agent) RPC(method string, args interface{}, reply interface{}) error {
 			method = e + "." + p[1]
 		}
 	}
-	a.endpointsLock.Unlock()
+	a.endpointsLock.RUnlock()
 	return a.delegate.RPC(method, args, reply)
 }