apapi

This is an asynchronous plugin for sampling PAPI performance counters.

Compilation and Installation

Prerequisites

To compile this plugin, you need:

GCC compiler (with std=11 support)
libpthread
CMake
PAPI (5.2+)
Score-P or VampirTrace (5.14+)

Building

Create a build directory
```
 mkdir build
 cd build
```
Invoke CMake

Specify the VampirTrace and/or Score-P and PAPI directory if it is not in the default path with -DVT_DIR=<PATH> and/or -DSCOREP_DIR=<PATH> respectivly -DPAPI_INC=<PATH>. The plugin will use alternatively the environment variables VT_DIR, SCOREP_DIR and PAPI_INC, e.g.
```
 cmake .. -DSCOREP_DIR=/opt/scorep -DPAPI_INC=/opt/papi/inc
```
Invoke make
```
 make
```
Copy it to a location listed in LD_LIBRARY_PATH or add current path to LD_LIBRARY_PATH with
```
 export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:`pwd`
```

Usage

Score-P

To use this plugin, add it to the SCOREP_METRIC_PLUGINS environment variable, e.g.:

export SCOREP_METRIC_PLUGINS="apapi_plugin"

All avaible papi counter should be avaible in this plugin. To use them, simply set the desired PAPI counters in the SCOREP_METRIC_APAPI_PLUGIN environment variable.

export SCOREP_METRIC_APAPI_PLUGIN="PAPI_L2_TCM,PAPI_FP_INS"

VampirTrace

All avaible papi counter should be avaible in this plugin. To use them, simply set the VT_PLUGIN_CNTR_METRICS environment variable. Prefix the PAPI counter name with A, e.g.

export VT_PLUGIN_CNTR_METRICS="apapi_plugin_L2_TCM:apapi_plugin_FP_INS"

Environment variables

SCOREP_METRIC_APAPI_INTERVAL_US/VT_APAPI_INTERVAL_US (default=100000)

Specifies the interval in usecs, at wich the performance counters are read. A higher interval means less disturbance, a lower interval provides more resolution.
SCOREP_METRIC_APAPI_BUF_SIZE/VT_APAPI_BUF_SIZE (default=4M)

The size of the buffer for storing samples. Can be suffixed with G, M, and K.

The buffer size is per thread, e.g., on a system with two papi counters, 12 threads and 4 MB buffer size this would be 48 MB in total. Typically, a sample consists of a 8 byte timestamp and 8 byte per selected counter.

If the buffer is too small, it might not be capable of storing all events. If this is the case, then a error message will be printed to stderr.

If anything fails

Check whether the plugin library can be loaded from the LD_LIBRARY_PATH.
Write a mail to the author.

Authors

Michael Werner (michael.werner3 at tu-dresden dot de)

score-p/scorep_plugin_apapi