Optimize default compile to compilation platform by default

Summary:
This diff changes compile to optimize for native platform by default. This will automatically turn on crc32 optimizations for modern processors, which greatly improves rocksdb's performance.

I also did some more changes to compilation documentation.

Test Plan:
compile with `make`, observe -march=native
compile with `PORTABLE=1 make`, observe no -march=native

Reviewers: sdong, rven, yhchiang, MarkCallaghan

Reviewed By: MarkCallaghan

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D30225

HISTORY.md

@@ -2,6 +2,7 @@
 
 ### Unreleased Features
 * Changed the LRU caching algorithm so that referenced blocks (by iterators) are never evicted
+* By default we now optimize the compilation for the compilation platform (using -march=native). If you want to build portable binary, use 'PORTABLE=1' before the make command.
 
 ### 3.9.0 (12/8/2014)
 

INSTALL.md

@@ -2,7 +2,7 @@
 
 RocksDB's library should be able to compile without any dependency installed,
 although we recommend installing some compression libraries (see below).
-We do depend on newer gcc with C++11 support.
+We do depend on newer gcc/clang with C++11 support.
 
 There are few options when compiling RocksDB:
 
@@ -15,9 +15,9 @@ There are few options when compiling RocksDB:
 * `make all` will compile our static library, and all our tools and unit tests. Our tools
 depend on gflags. You will need to have gflags installed to run `make all`.
 
-* if Intel SSE instruction set is supported, set USE_SSE=" -msse -msse4.2 " to make sure
-SSE4.2 is used to speed up CRC32 when calculating data checksum.
-
+* By default the binary we produce is optimized for the platform you're compiling on
+(-march=native). If you want to build a portable binary, add 'PORTABLE=1' before
+your make commands, like this: `PORTABLE=1 make static_lib`
 
 ## Dependencies
 
@@ -76,13 +76,7 @@ SSE4.2 is used to speed up CRC32 when calculating data checksum.
         * Install via [homebrew](http://brew.sh/).
             * If you're first time developer in MacOS, you still need to run: `xcode-select --install` in your command line.
             * run `brew tap homebrew/dupes; brew install gcc47 --use-llvm` to install gcc 4.7 (or higher).
-    * Install zlib, bzip2 and snappy libraries for compression.
-    * Install gflags. We have included a script
-    `build_tools/mac-install-gflags.sh`, which should automatically install it (execute this file instead of runing using "source" command).
-    If you installed gflags by other means (for example, `brew install gflags`),
-    please set `LIBRARY_PATH` and `CPATH` accordingly.
-    * Please note that some of the optimizations/features are disabled in OSX.
-    We did not run any production workloads on it.
+    * run `brew install rocksdb`
 
 * **iOS**:
   * Run: `TARGET_OS=IOS make static_lib`. When building the project which uses rocksdb iOS library, make sure to define two important pre-processing macros: `ROCKSDB_LITE` and `IOS_CROSS_COMPILE`.

build_tools/build_detect_platform

@@ -308,8 +308,12 @@ if test "$USE_HDFS"; then
   JAVA_LDFLAGS="$JAVA_LDFLAGS $HDFS_LDFLAGS"
 fi
 
-# if Intel SSE instruction set is supported, set USE_SSE=" -msse -msse4.2 "
-COMMON_FLAGS="$COMMON_FLAGS $USE_SSE"
+if test "$USE_SSE"; then
+  # if Intel SSE instruction set is supported, set USE_SSE=1
+  COMMON_FLAGS="$COMMON_FLAGS -msse -msse4.2 "
+elif test -z "$PORTABLE"; then
+  COMMON_FLAGS="$COMMON_FLAGS -march=native -mtune=native "
+fi
 
 PLATFORM_CCFLAGS="$PLATFORM_CCFLAGS $COMMON_FLAGS"
 PLATFORM_CXXFLAGS="$PLATFORM_CXXFLAGS $COMMON_FLAGS"

build_tools/fbcode_config.sh

@@ -48,7 +48,7 @@ LIBUNWIND_REV=2c060e64064559905d46fd194000d61592087bdc
 LIBUNWIND="/mnt/gvfs/third-party2/libunwind/$LIBUNWIND_REV/1.1/gcc-4.8.1-glibc-2.17/675d945/lib/libunwind.a"
 
 # use Intel SSE support for checksum calculations
-export USE_SSE=" -msse -msse4.2 "
+export USE_SSE=1
 
 BINUTILS="/mnt/gvfs/third-party2/binutils/2aff2e7b474cd3e6ab23495ad1224b7d214b9f8e/2.21.1/centos6-native/da39a3e/bin"
 AR="$BINUTILS/ar"