TestSuiteGuide.md 12.6 KB

Raw Blame History Permalink



test-suite Guide


Quickstart


The lit test runner is required to run the tests. You can either use one
from an LLVM build:


   % <path to llvm build>/bin/llvm-lit --version
   lit 0.8.0dev


An alternative is installing it as a python package in a python virtual
   environment:

   % mkdir venv
   % virtualenv venv
   % . venv/bin/activate
   % pip install svn+https://llvm.org/svn/llvm-project/llvm/trunk/utils/lit
   % lit --version
   lit 0.8.0dev


Check out the test-suite module with:


   % git clone https://github.com/llvm/llvm-test-suite.git test-suite


Create a build directory and use CMake to configure the suite. Use the
CMAKE_C_COMPILER option to specify the compiler to test. Use a cache file
to choose a typical build configuration:


   % mkdir test-suite-build
   % cd test-suite-build
   % cmake -DCMAKE_C_COMPILER=<path to llvm build>/bin/clang \
           -C../test-suite/cmake/caches/O3.cmake \
           ../test-suite


Build the benchmarks:


   % make
   Scanning dependencies of target timeit-target
   [  0%] Building C object tools/CMakeFiles/timeit-target.dir/timeit.c.o
   [  0%] Linking C executable timeit-target
   ...


Run the tests with lit:


   % llvm-lit -v -j 1 -o results.json .
   -- Testing: 474 tests, 1 threads --
   PASS: test-suite :: MultiSource/Applications/ALAC/decode/alacconvert-decode.test (1 of 474)
   ********** TEST 'test-suite :: MultiSource/Applications/ALAC/decode/alacconvert-decode.test' RESULTS **********
   compile_time: 0.2192
   exec_time: 0.0462
   hash: "59620e187c6ac38b36382685ccd2b63b"
   size: 83348
   **********
   PASS: test-suite :: MultiSource/Applications/ALAC/encode/alacconvert-encode.test (2 of 474)
   ...


Show and compare result files (optional):


   # Make sure pandas is installed. Prepend `sudo` if necessary.
   % pip install pandas
   # Show a single result file:
   % test-suite/utils/compare.py results.json
   # Compare two result files:
   % test-suite/utils/compare.py results_a.json results_b.json


Structure

The test-suite contains benchmark and test programs.  The programs come with
reference outputs so that their correctness can be checked.  The suite comes
with tools to collect metrics such as benchmark runtime, compilation time and
code size.

The test-suite is divided into several directories:


 SingleSource/


Contains test programs that are only a single source file in size.  A
   subdirectory may contain several programs.


 MultiSource/


Contains subdirectories which entire programs with multiple source files.
   Large benchmarks and whole applications go here.


 MicroBenchmarks/


Programs using the google-benchmark
   library. The programs define functions that are run multiple times until the
   measurement results are statistically significant.


 External/


Contains descriptions and test data for code that cannot be directly
   distributed with the test-suite. The most prominent members of this
   directory are the SPEC CPU benchmark suites.
   See External Suites.


 Bitcode/


These tests are mostly written in LLVM bitcode.


 CTMark/


Contains symbolic links to other benchmarks forming a representative sample
   for compilation performance measurements.


Benchmarks

Every program can work as a correctness test. Some programs are unsuitable for
performance measurements. Setting the TEST_SUITE_BENCHMARKING_ONLY CMake
option to ON will disable them.


Configuration

The test-suite has configuration options to customize building and running the
benchmarks. CMake can print a list of them:

% cd test-suite-build
# Print basic options:
% cmake -LH
# Print all options:
% cmake -LAH


Common Configuration Options


CMAKE_C_FLAGS


Specify extra flags to be passed to C compiler invocations.  The flags are
  also passed to the C++ compiler and linker invocations.  See
  https://cmake.org/cmake/help/latest/variable/CMAKE_LANG_FLAGS.html


CMAKE_C_COMPILER


Select the C compiler executable to be used. Note that the C++ compiler is
  inferred automatically i.e. when specifying path/to/clang CMake will
  automatically use path/to/clang++ as the C++ compiler.  See
  https://cmake.org/cmake/help/latest/variable/CMAKE_LANG_COMPILER.html


CMAKE_BUILD_TYPE


Select a build type like OPTIMIZE or DEBUG selecting a set of predefined
  compiler flags. These flags are applied regardless of the CMAKE_C_FLAGS
  option and may be changed by modifying CMAKE_C_FLAGS_OPTIMIZE etc.  See
  https://cmake.org/cmake/help/latest/variable/CMAKE_BUILD_TYPE.html


TEST_SUITE_RUN_UNDER


Prefix test invocations with the given tool. This is typically used to run
  cross-compiled tests within a simulator tool.


TEST_SUITE_BENCHMARKING_ONLY


Disable tests that are unsuitable for performance measurements. The disabled
  tests either run for a very short time or are dominated by I/O performance
  making them unsuitable as compiler performance tests.


TEST_SUITE_SUBDIRS


Semicolon-separated list of directories to include. This can be used to only
  build parts of the test-suite or to include external suites.  This option
  does not work reliably with deeper subdirectories as it skips intermediate
  CMakeLists.txt files which may be required.


TEST_SUITE_COLLECT_STATS


Collect internal LLVM statistics. Appends -save-stats=obj when invocing the
  compiler and makes the lit runner collect and merge the statistic files.


TEST_SUITE_RUN_BENCHMARKS


If this is set to OFF then lit will not actually run the tests but just
  collect build statistics like compile time and code size.


TEST_SUITE_USE_PERF


Use the perf tool for time measurement instead of the timeit tool that
  comes with the test-suite.  The perf is usually available on linux systems.


TEST_SUITE_SPEC2000_ROOT, TEST_SUITE_SPEC2006_ROOT, TEST_SUITE_SPEC2017_ROOT, ...


Specify installation directories of external benchmark suites. You can find
  more information about expected versions or usage in the README files in the
  External directory (such as External/SPEC/README)


Common CMake Flags


-GNinja


Generate build files for the ninja build tool.


-Ctest-suite/cmake/caches/<cachefile.cmake>


Use a CMake cache.  The test-suite comes with several CMake caches which
  predefine common or tricky build configurations.


Displaying and Analyzing Results

The compare.py script displays and compares result files.  A result file is
produced when invoking lit with the -o filename.json flag.

Example usage:


Basic Usage:


  % test-suite/utils/compare.py baseline.json
  Warning: 'test-suite :: External/SPEC/CINT2006/403.gcc/403.gcc.test' has No metrics!
  Tests: 508
  Metric: exec_time

  Program                                         baseline

  INT2006/456.hmmer/456.hmmer                   1222.90
  INT2006/464.h264ref/464.h264ref               928.70
  ...
               baseline
  count  506.000000
  mean   20.563098
  std    111.423325
  min    0.003400
  25%    0.011200
  50%    0.339450
  75%    4.067200
  max    1222.896800


Show compile_time or text segment size metrics:


  % test-suite/utils/compare.py -m compile_time baseline.json
  % test-suite/utils/compare.py -m size.__text baseline.json


Compare two result files and filter short running tests:


  % test-suite/utils/compare.py --filter-short baseline.json experiment.json
  ...
  Program                                         baseline  experiment  diff

  SingleSour.../Benchmarks/Linpack/linpack-pc     5.16      4.30        -16.5%
  MultiSourc...erolling-dbl/LoopRerolling-dbl     7.01      7.86         12.2%
  SingleSour...UnitTests/Vectorizer/gcc-loops     3.89      3.54        -9.0%
  ...


Merge multiple baseline and experiment result files by taking the minimum
runtime each:


  % test-suite/utils/compare.py base0.json base1.json base2.json vs exp0.json exp1.json exp2.json


Continuous Tracking with LNT

LNT is a set of client and server tools for continuously monitoring
performance. You can find more information at
https://llvm.org/docs/lnt. The official LNT instance
of the LLVM project is hosted at http://lnt.llvm.org.


External Suites

External suites such as SPEC can be enabled by either


placing (or linking) them into the test-suite/test-suite-externals/xxx directory (example: test-suite/test-suite-externals/speccpu2000)
using a configuration option such as -D TEST_SUITE_SPEC2000_ROOT=path/to/speccpu2000


You can find further information in the respective README files such as
test-suite/External/SPEC/README.

For the SPEC benchmarks you can switch between the test, train and
ref input datasets via the TEST_SUITE_RUN_TYPE configuration option.
The train dataset is used by default.


Custom Suites

You can build custom suites using the test-suite infrastructure. A custom suite
has a CMakeLists.txt file at the top directory. The CMakeLists.txt will be
picked up automatically if placed into a subdirectory of the test-suite or when
setting the TEST_SUITE_SUBDIRS variable:

% cmake -DTEST_SUITE_SUBDIRS=path/to/my/benchmark-suite ../test-suite


Profile Guided Optimization

Profile guided optimization requires to compile and run twice. First the
benchmark should be compiled with profile generation instrumentation enabled
and setup for training data. The lit runner will merge the profile files
using llvm-profdata so they can be used by the second compilation run.

Example:

# Profile generation run:
% cmake -DTEST_SUITE_PROFILE_GENERATE=ON \
        -DTEST_SUITE_RUN_TYPE=train \
        ../test-suite
% make
% llvm-lit .
# Use the profile data for compilation and actual benchmark run:
% cmake -DTEST_SUITE_PROFILE_GENERATE=OFF \
        -DTEST_SUITE_PROFILE_USE=ON \
        -DTEST_SUITE_RUN_TYPE=ref \
        .
% make
% llvm-lit -o result.json .


The TEST_SUITE_RUN_TYPE setting only affects the SPEC benchmark suites.


Cross Compilation and External Devices


Compilation

CMake allows to cross compile to a different target via toolchain files. More
information can be found here:


https://llvm.org/docs/lnt/tests.html#cross-compiling
https://cmake.org/cmake/help/latest/manual/cmake-toolchains.7.html


Cross compilation from macOS to iOS is possible with the
test-suite/cmake/caches/target-target-*-iphoneos-internal.cmake CMake cache
files; this requires an internal iOS SDK.


Running

There are two ways to run the tests in a cross compilation setting:


Via SSH connection to an external device: The TEST_SUITE_REMOTE_HOST option
should be set to the SSH hostname.  The executables and data files need to be
transferred to the device after compilation.  This is typically done via the
rsync make target.  After this, the lit runner can be used on the host
machine. It will prefix the benchmark and verification command lines with an
ssh command.


Example:

  % cmake -G Ninja -D CMAKE_C_COMPILER=path/to/clang \
          -C ../test-suite/cmake/caches/target-arm64-iphoneos-internal.cmake \
          -D TEST_SUITE_REMOTE_HOST=mydevice \
          ../test-suite
  % ninja
  % ninja rsync
  % llvm-lit -j1 -o result.json .


You can specify a simulator for the target machine with the
TEST_SUITE_RUN_UNDER setting. The lit runner will prefix all benchmark
invocations with it.


Running the test-suite via LNT

The LNT tool can run the test-suite. Use this when submitting test results to
an LNT instance.  See
https://llvm.org/docs/lnt/tests.html#llvm-cmake-test-suite
for details.


Running the test-suite via Makefiles (deprecated)

Note: The test-suite comes with a set of Makefiles that are considered
deprecated.  They do not support newer testing modes like Bitcode or
Microbenchmarks and are harder to use.

Old documentation is available in the
test-suite Makefile Guide.