From 17c8b25367859818b7aa5ec5466472f96f8c82e1 Mon Sep 17 00:00:00 2001
From: Tao Lv <tao.a.lv@intel.com>
Date: Mon, 7 Jan 2019 04:04:38 +0800
Subject: [PATCH] Fix USE_MKLDNN check in Makefile (#13775)

* fix makefile

* change make/config.mk

* add comments

* retrigger ci
---
 Makefile       | 2 +-
 make/config.mk | 6 ++++--
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/Makefile b/Makefile
index 56f2537d68ff..51914c4e2e5e 100644
--- a/Makefile
+++ b/Makefile
@@ -61,7 +61,7 @@ endif
 # use customized config file
 include $(config)
 
-ifndef $(USE_MKLDNN)
+ifndef USE_MKLDNN
 ifneq ($(UNAME_S), Darwin)
 ifneq ($(UNAME_S), Windows)
 ifeq ($(UNAME_P), x86_64)
diff --git a/make/config.mk b/make/config.mk
index 03f438db89d5..8a1aa2c165c4 100644
--- a/make/config.mk
+++ b/make/config.mk
@@ -98,8 +98,10 @@ USE_LIBJPEG_TURBO_PATH = NONE
 # use openmp for parallelization
 USE_OPENMP = 1
 
-# whether use MKL-DNN library
-USE_MKLDNN = 0
+# whether use MKL-DNN library: 0 = disabled, 1 = enabled
+# if USE_MKLDNN is not defined, MKL-DNN will be enabled by default on x86 Linux.
+# you can disable it explicity with USE_MKLDNN = 0
+USE_MKLDNN =
 
 # whether use NNPACK library
 USE_NNPACK = 0