From a87acf93d8705cccf91fda3c702da04c365d9e9d Mon Sep 17 00:00:00 2001
From: alexanderbazhenoff <bazhenoff.alexander@gmail.com>
Date: Thu, 25 Oct 2018 13:58:13 +0300
Subject: [PATCH] kvm: improved performance on creating VM  (#2923)

Improved performance on creating VM for KVM virtualization.

On a huge hosts every "ifconfig | grep" takes a lot of time (about 2.5-3 minutes on hosts with 500 machines). For example: ip link show dev $vlanDev > /dev/null is faster than ifconfig |grep -w $vlanDev > /dev/null. But using ip command is much better. Using this patch you can create 500s machine in 10 seconds. You don't need slow ifconfig prints anymore.
---
 scripts/vm/network/vnet/modifyvlan.sh | 14 +++-----------
 1 file changed, 3 insertions(+), 11 deletions(-)

diff --git a/scripts/vm/network/vnet/modifyvlan.sh b/scripts/vm/network/vnet/modifyvlan.sh
index 24a38a18050..affa7780a9f 100755
--- a/scripts/vm/network/vnet/modifyvlan.sh
+++ b/scripts/vm/network/vnet/modifyvlan.sh
@@ -48,11 +48,7 @@ addVlan() {
 	fi
 	
 	# is up?
-  	ifconfig |grep -w $vlanDev > /dev/null
-	if [ $? -gt 0 ]
-	then
-		ifconfig $vlanDev up > /dev/null
-	fi
+	ip link set $vlanDev up > /dev/null 2>/dev/null
 	
 	if [ ! -d /sys/class/net/$vlanBr ]
 	then
@@ -86,11 +82,7 @@ addVlan() {
 		fi
 	fi
 	# is vlanBr up?
-	ifconfig |grep -w $vlanBr > /dev/null
-	if [ $? -gt 0 ]
-	then
-		ifconfig $vlanBr up
-	fi
+	ip link set $vlanBr up > /dev/null 2>/dev/null
 
 	return 0
 }
@@ -109,7 +101,7 @@ deleteVlan() {
 		return 1
 	fi	
 
-	ifconfig $vlanBr down
+	ip link set $vlanBr down
 	
 	if [ $? -gt 0 ]
 	then