Add performance.md and add instruction for linking tcmalloc

1 files changed, 14 insertions, 1 deletions

diff --git a/benchmarks/README.md b/benchmarks/README.md
index 459c7b9d..8fbc6e18 100644
--- a/benchmarks/README.md
+++ b/benchmarks/README.md
@@ -3,7 +3,9 @@
 
 This directory contains benchmarking schemas and data sets that you
 can use to test a variety of performance scenarios against your
-protobuf language runtime.
+protobuf language runtime. If you are looking for performance 
+numbers of officially support languages, see [here](
+https://github.com/google/protobuf/blob/master/docs/Performance.md)
 
 ## Prerequisite
 
@@ -17,6 +19,11 @@ We are using [google/benchmark](https://github.com/google/benchmark) as the
 benchmark tool for testing cpp. This will be automaticly made during build the
 cpp benchmark.
 
+The cpp protobuf performance can be improved by linking with [tcmalloc library](
+https://gperftools.github.io/gperftools/tcmalloc.html). For using tcmalloc, you
+need to build [gpertools](https://github.com/gperftools/gperftools) to generate
+libtcmallc.so library.
+
 ### Java
 We're using maven to build the java benchmarks, which is the same as to build
 the Java protobuf. There're no other tools need to install. We're using
@@ -64,6 +71,12 @@ $ make java
 $ make cpp
 ```
 
+For linking with tcmalloc:
+
+```
+$ env LD_PRELOAD={directory to libtcmalloc.so} make cpp
+```
+
 ### Python:
 
 We have three versions of python protobuf implementation: pure python, cpp