Update the bionic benchmarks documentation.
Test: NA
Change-Id: I6b804a1655b5cb76f189366070d478680f40c5d1
diff --git a/benchmarks/README.md b/benchmarks/README.md
new file mode 100644
index 0000000..6501839
--- /dev/null
+++ b/benchmarks/README.md
@@ -0,0 +1,66 @@
+Bionic Benchmarks
+=================
+Bionic benchmarks is a command line tool for measuring the runtimes of libc functions. It is built
+on top of [Google benchmarks](https://github.com/google/benchmark) with some additions to organize
+tests into suites.
+
+Instructions for running these can be found in the platform_bionic README.
+
+## Suites
+
+Suites are stored in the `suites/` directory and can be chosen with the command line flag
+'--bionic_xml'. When operated without specifying an xml file, the default is to use the
+file called `full.xml` found in the directory `suites/` bound in the same directory
+as the bionic-benchmarks executable.
+
+To use a different xml file, use the `--bionic_xml=FILE.XML` option. By default, this
+option searches for the xml file in the `suites/` directory. If it doesn't exist
+in that directory then the file will be found as relative to the current
+directory. If the option specifies the full path to an xml file such as
+`/data/nativetest/suites/example.xml`, it will be used as is.
+
+If no xml file is specified through the command-line option, the default is to use `suites/full.xml`.
+However, for the host bionic benchmarks (bionic-benchmarks-glibc), the default
+is to use `suites/host.xml`.
+
+### Format
+
+The format for a benchmark is:
+
+```
+<fn>
+ <name>BM_sample_benchmark</name>
+ <cpu><optional_cpu_to_lock></cpu>
+ <iterations><optional_iterations_to_run></iterations>
+ <args><space separated list of function args|shorthand></args>
+</fn>
+```
+
+xml-specified values for iterations and cpu take precedence over those specified via command line
+(via '--bionic_iterations' and '--bionic_cpu', respectively.)
+
+To make small changes in runs, you can also schedule benchmarks by passing in their name and a
+space-separated list of arguments via the 'bionic_extra' command line flag, e.g.
+'--bionic_extra="BM_string_memcpy AT_COMMON_SIZES"' or '--bionic_extra="BM_string_memcmp 32 8 8"'
+
+Note that benchmarks will run normally if extra arguments are passed in, and it will fail
+with a segfault if too few are passed in.
+
+### Shorthand
+
+For the sake of brevity, multiple runs can be scheduled in one xml element by putting one of the
+following in the args field:
+
+ NUM_PROPS
+ MATH_COMMON
+ AT_ALIGNED_<ONE|TWO>BUF
+ AT_<any power of two between 2 and 16384>_ALIGNED_<ONE|TWO>BUF
+ AT_COMMON_SIZES
+
+Definitions for these can be found in bionic_benchmarks.cpp, and example usages can be found in
+the suites directory.
+
+### Unit Tests
+
+Bionic benchmarks also has its own set of unit tests, which can be run from the binary in
+`/data/nativetest[64]/bionic-benchmarks-tests`
diff --git a/benchmarks/run-on-host.sh b/benchmarks/run-on-host.sh
index bc63628..af96b27 100755
--- a/benchmarks/run-on-host.sh
+++ b/benchmarks/run-on-host.sh
@@ -12,7 +12,7 @@
)
exit 0
elif [ "$1" != 32 -a "$1" != 64 ]; then
- echo "Usage: $0 [ 32 | 64 | glibc ] [gtest flags]"
+ echo "Usage: $0 [ 32 | 64 | glibc ] [benchmark flags]"
exit 1
fi