Usage

Environment Variables

General

• SCOREP_METRIC_PLUGINS=metricq_plugin

• SCOREP_METRIC_METRICQ_PLUGIN (required)

  Comma-separated list of metrics. Metrics can also contain wildcards (*)

• SCOREP_METRIC_METRICQ_PLUGIN_SERVER (required)

  URL to the main MetricQ AMQP server including user/password.

• SCOREP_METRIC_METRICQ_PLUGIN_TIMEOUT (optional, default: 1 hour)

  Maximum duration of the experiment. It is strongly recommended to specify a value. If the value is too large and your measurement crashes, it may result in resource exhaustion of the measurement infrastructure. The value is a duration string which will be parsed, e.g. 1 hour.

• SCOREP_METRIC_METRICQ_PLUGIN_TOKEN (optional, default: "sink-scorep")

  Base token to use within MetricQ. A uuid is added internally. Default:

• SCOREP_METRIC_METRICQ_PLUGIN_VERBOSE (optional, default: info)

  Control output verbosity. Use one of trace,debug,info,warn,error,fatal.

• SCOREP_METRIC_METRICQ_PLUGIN_AVERAGE (optional, default: 0)

  Combine multiple high-resolution (>= 1 kSa/s) values to one. Set to e.g. 8 to reduce the number of values by a factor of 8. A setting of 0 disables averaging.

Time synchronization

Control the time synchronization. Each sync phase will last quantum * 2 ^ exponent + 2 * tolerance.

• tolerance is an upper bound of possible time shift. However, larger values increase the synchronization time.
• quantum should be a time interval that your sampling rate can properly observe.
• exponent is used to balance the duration in combination with the quntum. Larger exponent means more reliable synchronization, but also longer sync time. The exponent can range from 3 to 14.
• sampling is used when resampling the metric value stream to a truly fixed sampling rate. For best results, tt should be smaller than your actual sampling interval. However, too small values together with long synchronizations can lead make the FFT very computationally expensive.

The defaults are:

SCOREP_METRIC_METRICQ_PLUGIN_SYNC_TOLERANCE=2s
SCOREP_METRIC_METRICQ_PLUGIN_SYNC_QUANTUM=1ms
SCOREP_METRIC_METRICQ_PLUGIN_SYNC_EXPONENT=11
SCOREP_METRIC_METRICQ_PLUGIN_SYNC_SAMPLING=5us

Those default values have been used for measurements with ~151 kSa/s and seemed to work fine in practice.

• SCOREP_METRIC_METRICQ_PLUGIN_CORRELATION_FILE (optional)

  Prefix for writing a file containing correlation values for all offsets. This is only used for the most hardcore timesync debugging.

Time synchronization is only applied to metrics with >= 1 kSa/s. It uses the first of such metrics to determine the offset, so be wary of the order in which metrics are specified. Using wildcards is not recommended with that.

Recommended Score-P settings

Because the Score-P default settings are not appropriate for many use-cases:

SCOREP_ENABLE_PROFILING=false
SCOREP_ENABLE_TRACING=true