docs: function(counterName, seriesName, ts, s) {
        var value = parseInt(s);
        var counter = this.model_.kernel.
            getOrCreateCounter('DVFS', counterName);
        if (counter.numSeries === 0) {
          counter.addSeries(new tr.model.CounterSeries(seriesName,
              ColorScheme.getColorIdForGeneralPurposeString(counter.name)));
        }
        counter.series.forEach(function(series) {
          series.addCounterSample(ts, value);
        });
      }