diff --git a/docs/benchmark/README.md b/docs/benchmark/README.md
index e0fed6c..6e36123 100644
--- a/docs/benchmark/README.md
+++ b/docs/benchmark/README.md
@@ -11,13 +11,12 @@ We use [iperf](https://en.wikipedia.org/wiki/Iperf) as network bandwidth measure
 
 ## Preparations
 
-### 1. clone and install blinksocks globally
+### 1. clone and install dependencies
 
 ```
 $ git clone https://github.com/blinksocks/blinksocks
 $ cd blinksocks
 $ npm install
-$ npm install -g .
 ```
 
 ### 2. prepare test cases
@@ -46,75 +45,79 @@ Here is an example output about network performance of different [shadowsocks st
 
 ```
 blinksocks version:
-2.6.3
+2.8.4
 
 Operating System:
 cpu             Intel(R) Core(TM) i3-4160 CPU @ 3.60GHz
 cores           4
-memory          16722886656
+memory          16722878464
 type            Linux
 platform        linux
 arch            x64
-release         4.4.0-96-generic
+release         4.4.0-101-generic
 
 Node.js Versions:
 http_parser     2.7.0
-node            8.6.0
-v8              6.0.287.53
-uv              1.14.1
+node            8.9.3
+v8              6.1.534.48
+uv              1.15.0
 zlib            1.2.11
 ares            1.10.1-DEV
 modules         57
 nghttp2         1.25.0
-openssl         1.0.2l
+openssl         1.0.2n
 icu             59.1
 unicode         9.0
 cldr            31.0.1
 tz              2017b
 
-running tests...
+running 4 tests...
 
 ------------ Test Case 0 ----------------
 [{"name":"ss-base"},{"name":"ss-stream-cipher","params":{"method":"aes-256-ctr"}}]
 Interval         Transfer     Bitrate
-0.00-3.00   sec  1.89 GBytes  5.42 Gbits/sec  sender
-0.00-3.11   sec  1.77 GBytes  4.88 Gbits/sec  receiver
+0.00-3.00   sec  1.84 GBytes  5.26 Gbits/sec  sender
+0.00-3.12   sec  1.71 GBytes  4.71 Gbits/sec  receiver
 -----------------------------------------
 
 ------------ Test Case 1 ----------------
 [{"name":"ss-base"},{"name":"ss-stream-cipher","params":{"method":"aes-256-cfb"}}]
 Interval         Transfer     Bitrate
-0.00-3.00   sec  994 MBytes  2.78 Gbits/sec  sender
-0.00-3.31   sec  890 MBytes  2.26 Gbits/sec  receiver
+0.00-3.00   sec  972 MBytes  2.72 Gbits/sec  sender
+0.00-3.30   sec  856 MBytes  2.18 Gbits/sec  receiver
 -----------------------------------------
 
 ------------ Test Case 2 ----------------
 [{"name":"ss-base"},{"name":"ss-stream-cipher","params":{"method":"camellia-256-cfb"}}]
 Interval         Transfer     Bitrate
-0.00-3.00   sec  502 MBytes  1.40 Gbits/sec  sender
-0.00-3.73   sec  394 MBytes  887 Mbits/sec  receiver
+0.00-3.00   sec  510 MBytes  1.43 Gbits/sec  sender
+0.00-3.58   sec  382 MBytes  896 Mbits/sec  receiver
 -----------------------------------------
 
 ------------ Test Case 3 ----------------
 [{"name":"ss-base"},{"name":"ss-aead-cipher","params":{"method":"aes-256-gcm"}}]
 Interval         Transfer     Bitrate
-0.00-3.00   sec  804 MBytes  2.25 Gbits/sec  sender
-0.00-3.31   sec  489 MBytes  1.24 Gbits/sec  receiver
+0.00-3.00   sec  731 MBytes  2.04 Gbits/sec  sender
+0.00-3.89   sec  642 MBytes  1.38 Gbits/sec  receiver
 -----------------------------------------
 
 (ranking):
 
- 1: Test Case 0, Bitrate=[5.42 Gbits/sec, 4.88 Gbits/sec], [{"name":"ss-base"},{"name":"ss-stream-cipher","params":{"method":"aes-256-ctr"}}]
- 2: Test Case 1, Bitrate=[2.78 Gbits/sec, 2.26 Gbits/sec], [{"name":"ss-base"},{"name":"ss-stream-cipher","params":{"method":"aes-256-cfb"}}]
- 3: Test Case 3, Bitrate=[2.25 Gbits/sec, 1.24 Gbits/sec], [{"name":"ss-base"},{"name":"ss-aead-cipher","params":{"method":"aes-256-gcm"}}]
- 4: Test Case 2, Bitrate=[1.40 Gbits/sec, 887 Mbits/sec], [{"name":"ss-base"},{"name":"ss-stream-cipher","params":{"method":"camellia-256-cfb"}}]
+ 1: Test Case 0, Bitrate = 5.26 Gbits/sec, 4.71 Gbits/sec
+    [{"name":"ss-base"},{"name":"ss-stream-cipher","params":{"method":"aes-256-ctr"}}]
+ 2: Test Case 1, Bitrate = 2.72 Gbits/sec, 2.18 Gbits/sec
+    [{"name":"ss-base"},{"name":"ss-stream-cipher","params":{"method":"aes-256-cfb"}}]
+ 3: Test Case 3, Bitrate = 2.04 Gbits/sec, 1.38 Gbits/sec
+    [{"name":"ss-base"},{"name":"ss-aead-cipher","params":{"method":"aes-256-gcm"}}]
+ 4: Test Case 2, Bitrate = 1.43 Gbits/sec, 896 Mbits/sec
+    [{"name":"ss-base"},{"name":"ss-stream-cipher","params":{"method":"camellia-256-cfb"}}]
 
-Done in 59.51s.
+Done in 61.94s.
 ```
 
 As you can see, the program first lists **blinksocks version**, **Operating System** and **Node.js Versions** parameters of the current platform.
 
-Following the parameters, there are 3 test cases, each test case has different configuration(presets) defined in [benchmark/cases.js]. Test results are followed by configuration line.
+Following the parameters, there are 4 test cases, each test case has different configuration(presets) defined in [benchmark/cases.js]. Test results are followed by configuration line.
 
 The first line of results represents traffic from `iperf -c` to `bs-client` while the second represents traffic from `bs-server` to `iperf -s`.
 
@@ -125,7 +128,7 @@ The first line of results represents traffic from `iperf -c` to `bs-client` whil
 
 > You'd better check out [benchmark/iperf.sh] and figure out how it works.
 
-**In my environment**, `aes-256-ctr` has the maximum transfer and bitrate among these 4 test cases.
+**In my environment**, stream cipher with `aes-256-ctr` encryption method has the maximum transfer as well as bitrate among these 4 test cases.
 
 ## History Reports