From 2982f2e3659342c9107cf5c054d1db5f9043efe9 Mon Sep 17 00:00:00 2001
From: Alex Dadgar <alex.dadgar@gmail.com>
Date: Wed, 17 Feb 2016 13:50:06 -0800
Subject: [PATCH] Disable half the workers, freeing half the CPUs

---
 nomad/leader.go | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/nomad/leader.go b/nomad/leader.go
index ce60966f4e44..229a9f2191ef 100644
--- a/nomad/leader.go
+++ b/nomad/leader.go
@@ -98,10 +98,13 @@ WAIT:
 // previously inflight transactions have been commited and that our
 // state is up-to-date.
 func (s *Server) establishLeadership(stopCh chan struct{}) error {
-	// If we have multiple workers, disable one to free processing
-	// for the plan queue and evaluation broker
-	if len(s.workers) > 1 {
-		s.workers[0].SetPause(true)
+	// Disable workers to free half the cores for use in the plan queue and
+	// evaluation broker
+	if numWorkers := len(s.workers); numWorkers > 1 {
+		// Disabling half the workers frees half the CPUs.
+		for i := 0; i < numWorkers / 2; i++ {
+			s.workers[i].SetPause(true)
+		}
 	}
 
 	// Enable the plan queue, since we are now the leader
@@ -363,7 +366,9 @@ func (s *Server) revokeLeadership() error {
 
 	// Unpause our worker if we paused previously
 	if len(s.workers) > 1 {
-		s.workers[0].SetPause(false)
+		for i := 0; i < len(s.workers) / 2; i++ {
+			s.workers[i].SetPause(false)
+		}
 	}
 	return nil
 }