hwcinstr

Clang + LLVM plugin to automatically add PAPI instrumentation to code

Build

Requirements

• PAPI
• libyaml
• libopenssl

Build instructions

It is not recommended to build in the source directory. One suggestion to build would be:

$ git clone [email protected]:tarunprabhu/hwcinstr.git
$ mkdir build
$ cd build
$ cmake -DCMAKE_CXX_COMPILER=clang++ -DCMAKE_INSTALL_PREFIX=/path/to/install /path/to/hwcinstr

If clang, libyaml, PAPI etc. are in non-standard paths, CMAKE_PREFIX_PATH may be set to the appropriate directories

Usage

hwcc and hwc++ are the drivers that can be found in /path/to/install/bin They can mostly be used as drop-in replacements of a regular compiler

$ hwcc --conf /path/to/conf/file <regular compiler arguments>

Config file

The list of available counters on the current system can be obtained from PAPI:

$ papi_avail -a

The output of this command may look something like this

PAPI_L2_DCM  0x80000002  Yes  Level 2 data cache misses
PAPI_L1_TCM  0x80000006  Yes  Level 1 cache misses
...
... <more counters follow>

The counters specified in the config file must be the same as those in the first column of the output above without the PAPI_ prefix

The config file is a YAML file. An example config file can be found in the sample directory

TODO

• Support GCC as well by writing a GCC plugin that does similar things
• Support C++11 function attributes that can be used instead of a config file
• Allow different counters to be captured for each function
• Support counters around arbitrary regions
• Support turning on and off counters so that calls will only be instrumented once capture has been explicitly turned on