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CSSTUDIO-3420 Performance improvements to the Waterfall Plot widget #3544

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Merged
abrahamwolk merged 3 commits into from
Sep 12, 2025
Merged

CSSTUDIO-3420 Performance improvements to the Waterfall Plot widget #3544

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5f707e4
CSSTUDIO-3420 Change type from TreeMap to ConcurrentSkipListMap, and …
abrahamwolk Sep 11, 2025
0a56674
CSSTUDIO-3420 Change type from LinkedList<Double> to ArrayList<Double…
abrahamwolk Sep 11, 2025
4d604e6
CSSTUDIO-3420 Change type from LinkedList<> to ArrayList<> for 'pvNam…
abrahamwolk Sep 11, 2025
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43 changes: 22 additions & 21 deletions ...t/src/main/java/org/phoebus/applications/waterfallplotwidget/WaterfallPlotController.java
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Original file line number Diff line number Diff line change
Expand Up @@ -17,13 +17,12 @@

import java.time.Duration;
import java.time.Instant;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
import java.util.Optional;
import java.util.SortedMap;
import java.util.TreeMap;
import java.util.concurrent.ConcurrentSkipListMap;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicReference;

public class WaterfallPlotController {

Expand Down Expand Up @@ -309,7 +308,7 @@ public synchronized void redraw(WaterfallPlotRuntime.PVData pvData) {
previousT2[0] = Optional.of(t2);

LinkedList<Double> timeValuesLinkedList = new LinkedList<>();
LinkedList<LinkedList<Double>> zValuesLinkedList = new LinkedList<>();
LinkedList<ArrayList<Double>> zValuesLinkedList = new LinkedList<>();
int waveformLength = 1;

double minFromPV = Double.NaN;
Expand All @@ -320,21 +319,24 @@ public synchronized void redraw(WaterfallPlotRuntime.PVData pvData) {
minFromPV = waveformPVData.minFromPV().get();
maxFromPV = waveformPVData.maxFromPV().get();

TreeMap<Instant, LinkedList<Double>> instantToWaveform = waveformPVData.instantToValue().get();
ConcurrentSkipListMap<Instant, ArrayList<Double>> instantToWaveform = waveformPVData.instantToValue();
Instant startKey = instantToWaveform.ceilingKey(Instant.MIN);
for (Instant t = t1.plus(stepsize); t.compareTo(t2) <= 0; t = t.plus(stepsize)) {
timeValuesLinkedList.add(((double) t.toEpochMilli()) / 1000.0);

var instant = instantToWaveform.floorKey(t);
if (instant != null) {
LinkedList<Double> waveform = instantToWaveform.get(instant);
if (startKey == null || t.isBefore(startKey)) {
zValuesLinkedList.add(null); // null means absence of data for this point in time
}
else {
var instant = instantToWaveform.floorKey(t);

ArrayList<Double> waveform = instantToWaveform.get(instant);
waveformLength = Math.max(waveformLength, waveform.size());
zValuesLinkedList.add(waveform);
} else {
zValuesLinkedList.add(null); // null means absence of data for this point in time
}
}
} else if (pvData instanceof WaterfallPlotRuntime.ScalarPVsData scalarPVsData) {
LinkedList<Pair<String, AtomicReference<TreeMap<Instant, Double>>>> pvNameToInstantToValue = scalarPVsData.pvNameToInstantToValue();
ArrayList<Pair<String, ConcurrentSkipListMap<Instant, Double>>> pvNameToInstantToValue = scalarPVsData.pvNameToInstantToValue();
pvNameToInstantToValue.forEach(pvNameAndInstantToValueAtomicReference -> garbageCollectInstantToValue(pvNameAndInstantToValueAtomicReference.getValue(), t1));

minFromPV = scalarPVsData.minFromPV().get();
Expand All @@ -344,12 +346,12 @@ public synchronized void redraw(WaterfallPlotRuntime.PVData pvData) {

for (Instant t = t1.plus(stepsize); t.compareTo(t2) <= 0; t = t.plus(stepsize)) {
timeValuesLinkedList.add(((double) t.toEpochMilli()) / 1000.0);
LinkedList<Double> zValues = new LinkedList<>();
ArrayList<Double> zValues = new ArrayList<>();

for (var pvNameAndInstantToValue : pvNameToInstantToValue) {
String pvName = pvNameAndInstantToValue.getKey();

TreeMap<Instant, Double> instantToValue = pvNameAndInstantToValue.getValue().get();
ConcurrentSkipListMap<Instant, Double> instantToValue = pvNameAndInstantToValue.getValue();

var instant = instantToValue.floorKey(t);
if (instant == null) {
Expand All @@ -363,7 +365,7 @@ public synchronized void redraw(WaterfallPlotRuntime.PVData pvData) {

// Append the last value one more time in order to
// fix the plotting when there is only 1 scalar PV:
var lastValue = zValues.getLast();
var lastValue = zValues.get(zValues.size()-1);
zValues.add(lastValue);

zValuesLinkedList.add(zValues);
Expand Down Expand Up @@ -392,7 +394,7 @@ public synchronized void redraw(WaterfallPlotRuntime.PVData pvData) {
}

for (int n = 0; n < zValuesLinkedList.size(); n++) {
LinkedList<Double> waveformValues = zValuesLinkedList.get(n);
ArrayList<Double> waveformValues = zValuesLinkedList.get(n);

for (int m = 0; m < waveformLength; m++) {
double value;
Expand Down Expand Up @@ -431,7 +433,7 @@ public synchronized void redraw(WaterfallPlotRuntime.PVData pvData) {
}

for (int n = 0; n < zValuesLinkedList.size(); n++) {
LinkedList<Double> waveformValues = zValuesLinkedList.get(n);
ArrayList<Double> waveformValues = zValuesLinkedList.get(n);

for (int m = 0; m < waveformLength; m++) {
double value;
Expand Down Expand Up @@ -479,14 +481,13 @@ else if (zAxisMinMax.equals(WaterfallPlotWidget.ZAxisMinMax.FromPVLimits)) {
}
}

private synchronized static <T> void garbageCollectInstantToValue(AtomicReference<TreeMap<Instant, T>> instantToValueAtomicReference, Instant t1) {
private synchronized static <T> void garbageCollectInstantToValue(ConcurrentSkipListMap<Instant, T> instantToWaveform, Instant t1) {
// Garbage collect old values that are no longer needed:
TreeMap<Instant, T> instantToWaveform = instantToValueAtomicReference.get();
Instant instantOfOldestRelevantKey = instantToWaveform.floorKey(t1);
if (instantOfOldestRelevantKey != null) {
SortedMap<Instant, T> instantToWaveformGarbageCollectedSortedMap = instantToWaveform.subMap(instantOfOldestRelevantKey, Instant.MAX);
TreeMap<Instant, T> instantToWaveformGarbageCollected = new TreeMap<>(instantToWaveformGarbageCollectedSortedMap);
instantToValueAtomicReference.set(instantToWaveformGarbageCollected);
for (var key : instantToWaveform.subMap(Instant.MIN, instantOfOldestRelevantKey).keySet()) {
instantToWaveform.remove(key);
}
}
}

Expand Down
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