Score-P/VampirTrace perf Plugin Counter Component

Compilation and Installation

Prerequisites

To compile this plugin, you need:

• C compiler

• CMake

• Score-P (or VampirTrace)

• A recent Linux kernel (2.6.32+) with activated tracing and the kernel headers

Building

1. Create a build directory

    mkdir build
    cd build
   

2. Invoke CMake

   Specify the Score-P directory if it is not in the default path with -DSCOREP_DIR=<PATH> (or -DVT_INC=<PATH> for VampirTrace respectively). The plugin will use alternatively the environment variables SCOREP_DIR (respectively VT_DIR), e.g.

    cmake .. -DSCOREP_DIR=/opt/scorep
   

   or (for VampirTrace)

    cmake .. -DVT_DIR=/opt/vampirtrace
   

3. Invoke make

    make
   

4. 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

Before using this, be sure that you are allowed to measure the counters. For unprivileged users, it might be necessary to change the paranoid level in /proc/sys/kernel/perf_event_paranoid. It should be 0 or -1.

Paranoid levels:

• -1 - not paranoid at all

• 0 - disallow raw tracepoint access for unpriv

• 1 - disallow cpu events for unpriv

• 2 - disallow kernel profiling for unpriv

Please check your /sys/bus/event_source/devices/ folder for event sources, e.g. /sys/bus/event_source/devices/uncore_imc_0/ is the integrated memory controller of NUMA node 0 on Intel Sandy Bridge EP or /sys/bus/event_source/devices/power/ on some systems with RAPL available.

In these folders there might be predefined events, e.g., some systems provide:

/sys/bus/event_source/devices/power/events/energy-cores

These events can be used additional to explicit ones. Examples are:

• Explicit

  "uncore_imc_0/event=0xff,umask=0x00" (memory controller cycles on sandy Bridge)

• Predefined

  "power/energy-cores" (energy in Joules used to operate processor cores according to RAPL)

Score-P

To use this plugin, you have to add it to the SCOREP_METRIC_PLUGINS environment variable. Afterwards you can add the events that shall be recorded to the SCOREP_METRIC_PERFCOMPONENT_PLUGIN variable, e.g.:

export SCOREP_METRIC_PLUGINS="perfcomponent_plugin"
export SCOREP_METRIC_PLUGINS_SEP=";"
export SCOREP_METRIC_PERFCOMPONENT_PLUGIN="uncore_imc_0/event=0xff,umask=0x00"

or

export SCOREP_METRIC_PERFCOMPONENT_PLUGIN="power/energy-cores"

In the first case, it is required to change the metric seperator because the default is "," and will lead to a wrong interpretation.

Other Environment Variables:

• SCOREP_METRIC_PERFCOMPONENT_DELTA_TIME=(integer) sets the maximal interval in which the single metrics are retrieved. By default, they are retrieved for every event. With this environment variable they will only be retrieved every (integer) clock ticks (depending on the used SCOREP_TIMER). This only works with profiling disabled.

• SCOREP_METRIC_PERFCOMPONENT_HOST=(boolean) if set to TRUE/True/true/1, the metrics will be read only per host, not per thread. This only works with profiling disabled.

VampirTrace

To add a kernel event counter to your trace, you have to specify the environment variable VT_PLUGIN_CNTR_METRIC.

VT_PLUGIN_CNTR_METRIC specifies the software events that shall be recorded when tracing an application. You can add metrics that are available on your system. These can be predefined or explicit. Each event consists of an event source and an event definition.

E.g.:

export VT_PLUGIN_CNTR_METRICS="perfcomponent_plugin_uncore_imc_0/event=0xff,umask=0x00"

or

export VT_PLUGIN_CNTR_METRICS="perfcomponent_plugin_power/energy-cores"

If anything fails

1. Check whether the plugin library can be loaded from the LD_LIBRARY_PATH.

2. Check your paranoid level in /proc/sys/kernel/perf_event_paranoid. It should be 0 or -1.

3. Write a mail to the author.

Author

• Robert Schoene (robert.schoene at tu-dresden dot de)