//perf fix: only process elements between time and last processed - sampler duration
    private void rebuildAggRow(GraphRowSimple row, long time, long duration) {
        long key = row.getHigherKey(lastAggUpdateTime - duration - 1);
        while (key < time && key != -1) {
            GraphPanelChartSimpleElement elt = (GraphPanelChartSimpleElement) row.getElement(key);
            elt.add(getAllThreadCount(key));
            Long nextKey = row.getHigherKey(key);
            if (nextKey != null) {
                key = nextKey;
            } else {