srdo commented on a change in pull request #3092: STORM-3474 Large fragmented
cluster scheduling time test
URL: https://github.com/apache/storm/pull/3092#discussion_r309609442
##########
File path:
storm-server/src/test/java/org/apache/storm/scheduler/resource/TestResourceAwareScheduler.java
##########
@@ -1067,6 +1068,208 @@ public void minCpuWorkerSplitFails() {
assertFalse("Topo-1 unscheduled?",
cluster.getAssignmentById(topo1.getId()) != null);
}
+ protected static class TimeBlockResult {
+ long firstBlockTime;
+ long lastBlockTime;
+ }
+
+ private long getMedianBlockTime(TimeBlockResult[] runResults, boolean
firstBlock) {
+ final int numRuns = runResults.length;
+ assert(numRuns % 2 == 1); // number of runs must be odd to compute
median as below
+ long[] times = new long[numRuns];
+ for (int i = 0; i < numRuns; ++i) {
+ times[i] = firstBlock ? runResults[i].firstBlockTime :
runResults[i].lastBlockTime;
+ }
+ Arrays.sort(times);
+
+ final int medianIndex = (int) Math.floor(numRuns / 2);
+ return times[medianIndex];
+ }
+
+ /**
+ * Check time to schedule a fragmented cluster using different strategies
+ *
+ * Simulate scheduling on a large production cluster. Find the ratio of
time to schedule a set of topologies when
+ * the cluster is empty and when the cluster is nearly full. While the
cluster has sufficient resources to schedule
+ * all topologies, when nearly full the cluster becomes fragmented and
some topologies fail to schedule.
+ */
+ @Test
+ public void TestLargeFragmentedClusterScheduling() {
+ /*
+ Without fragmentation, the cluster would be able to schedule both
topologies on each node. Let's call each node
+ with both topologies scheduled as 100% scheduled.
+
+ We schedule the cluster in 3 blocks of topologies, measuring the time
to schedule the blocks. The first, middle
+ and last blocks attempt to schedule the following 0-10%, 10%-90%,
90%-100%. The last block has a number of
+ scheduling failures due to cluster fragmentation and its time is
dominated by attempting to evict topologies.
+
+ Timing results for scheduling are noisy. As a result, we do multiple
runs and use median values for FirstBlock
+ and LastBlock times. (somewhere a statistician is crying). The ratio
of LastBlock / FirstBlock remains fairly constant.
+
+
+ TestLargeFragmentedClusterScheduling took 91118 ms
+ DefaultResourceAwareStrategy, FirstBlock 249.0, LastBlock 1734.0 ratio
6.963855421686747
+ GenericResourceAwareStrategy, FirstBlock 215.0, LastBlock 1673.0 ratio
7.78139534883721
+ ConstraintSolverStrategy, FirstBlock 279.0, LastBlock 2200.0 ratio
7.885304659498208
+
+ TestLargeFragmentedClusterScheduling took 98455 ms
+ DefaultResourceAwareStrategy, FirstBlock 266.0, LastBlock 1812.0 ratio
6.81203007518797
+ GenericResourceAwareStrategy, FirstBlock 235.0, LastBlock 1802.0 ratio
7.6680851063829785
+ ConstraintSolverStrategy, FirstBlock 304.0, LastBlock 2320.0 ratio
7.631578947368421
+
+ TestLargeFragmentedClusterScheduling took 97268 ms
+ DefaultResourceAwareStrategy, FirstBlock 251.0, LastBlock 1826.0 ratio
7.274900398406374
+ GenericResourceAwareStrategy, FirstBlock 220.0, LastBlock 1719.0 ratio
7.8136363636363635
+ ConstraintSolverStrategy, FirstBlock 296.0, LastBlock 2469.0 ratio
8.341216216216216
+
+ TestLargeFragmentedClusterScheduling took 97963 ms
+ DefaultResourceAwareStrategy, FirstBlock 249.0, LastBlock 1788.0 ratio
7.180722891566265
+ GenericResourceAwareStrategy, FirstBlock 240.0, LastBlock 1796.0 ratio
7.483333333333333
+ ConstraintSolverStrategy, FirstBlock 328.0, LastBlock 2544.0 ratio
7.7560975609756095
+
+ TestLargeFragmentedClusterScheduling took 93106 ms
+ DefaultResourceAwareStrategy, FirstBlock 258.0, LastBlock 1714.0 ratio
6.6434108527131785
+ GenericResourceAwareStrategy, FirstBlock 215.0, LastBlock 1692.0 ratio
7.869767441860465
+ ConstraintSolverStrategy, FirstBlock 309.0, LastBlock 2342.0 ratio
7.5792880258899675
+
+ Choose the median value of the values above
+ DefaultResourceAwareStrategy 6.96
+ GenericResourceAwareStrategy 7.78
+ ConstraintSolverStrategy 7.75
+ */
+
+ final int numNodes = 500;
+ final String[] strategies = new String[]{
+ DefaultResourceAwareStrategy.class.getName(),
+ GenericResourceAwareStrategy.class.getName(),
+ ConstraintSolverStrategy.class.getName()
+ };
+
+ final int numStrategies = strategies.length;
+ final int numRuns = 5;
+ TimeBlockResult testResults[][] = new
TimeBlockResult[numStrategies][numRuns];
+
+ // Get first and last block times for multiple runs and strategies
+ long startTime = Time.currentTimeMillis();
+ for (int strategyIdx = 0; strategyIdx < numStrategies; ++strategyIdx) {
+ String strategy = strategies[strategyIdx];
+
+ for (int run = 0; run < numRuns; ++run) {
+ testResults[strategyIdx][run] =
testLargeClusterSchedulingTiming(numNodes, strategy);
+ }
+ }
+
+ // Log median ratios for different strategies
+ LOG.info("TestLargeFragmentedClusterScheduling took {} ms",
Time.currentTimeMillis() - startTime);
+ for (int strategyIdx = 0; strategyIdx < numStrategies; ++strategyIdx) {
+ double medianFirstBlockTime =
getMedianBlockTime(testResults[strategyIdx], true);
+ double medianLastBlockTime =
getMedianBlockTime(testResults[strategyIdx], false);
+ double ratio = medianLastBlockTime / medianFirstBlockTime;
+ LOG.info("{}, FirstBlock {}, LastBlock {} ratio {}",
strategies[strategyIdx], medianFirstBlockTime, medianLastBlockTime, ratio);
+ }
+
+ // Check last block scheduling time does not get significantly slower
+ final double[] acceptedStrategyTimeRatios = {6.96, 7.78, 7.75};
Review comment:
How did you find these values?
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