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author | Ivan Topolnjak <ivantopo@gmail.com> | 2014-01-24 00:40:03 -0300 |
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committer | Ivan Topolnjak <ivantopo@gmail.com> | 2014-01-24 00:40:03 -0300 |
commit | c140f7530b80b597ab52b08c41e8f56b52ba22ed (patch) | |
tree | a8d3761dc0142acc2183970009f0277b309f7db5 /kamon-core/src/main/scala/kamon/metrics | |
parent | db4106fffca8dd2c83ee5c21a8b10eef945e9e75 (diff) | |
download | Kamon-c140f7530b80b597ab52b08c41e8f56b52ba22ed.tar.gz Kamon-c140f7530b80b597ab52b08c41e8f56b52ba22ed.tar.bz2 Kamon-c140f7530b80b597ab52b08c41e8f56b52ba22ed.zip |
hdr histogram extension with concurrent updates and snapshots support
Diffstat (limited to 'kamon-core/src/main/scala/kamon/metrics')
-rw-r--r-- | kamon-core/src/main/scala/kamon/metrics/AtomicSnapshotableHistogram.scala | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/kamon-core/src/main/scala/kamon/metrics/AtomicSnapshotableHistogram.scala b/kamon-core/src/main/scala/kamon/metrics/AtomicSnapshotableHistogram.scala new file mode 100644 index 00000000..39d4ac0b --- /dev/null +++ b/kamon-core/src/main/scala/kamon/metrics/AtomicSnapshotableHistogram.scala @@ -0,0 +1,78 @@ +/* + * ========================================================================================= + * Copyright © 2013 the kamon project <http://kamon.io/> + * + * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file + * except in compliance with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software distributed under the + * License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, + * either express or implied. See the License for the specific language governing permissions + * and limitations under the License. + * ========================================================================================= + */ + +package org.HdrHistogram + +import java.util.concurrent.atomic.AtomicLongFieldUpdater +import scala.annotation.tailrec +import org.HdrHistogram.AtomicSnapshotableHistogram.{Value, Snapshot} + + +/** + * This implementation aims to be used for real time data collection where data snapshots are taken often over time. + * The snapshotAndReset() operation extracts all the recorded values from the histogram and resets the counts, but still + * leave it in a consistent state even in the case of concurrent modification while the snapshot is being taken. + */ +class AtomicSnapshotableHistogram(highestTrackableValue: Long, numberOfSignificantValueDigits: Int) + extends AtomicHistogram(1L, highestTrackableValue, numberOfSignificantValueDigits) { + + import AtomicSnapshotableHistogram.totalCountUpdater + + + def snapshotAndReset(): Snapshot = { + val entries = Vector.newBuilder[Value] + val countsLength = counts.length() + + @tailrec def iterate(index: Int, previousValue: Long, nrOfRecordings: Long, bucketLimit: Long, increment: Long): Long = { + if(index < countsLength) { + val currentValue = previousValue + increment + val countAtValue = counts.getAndSet(index, 0) + + if(countAtValue > 0) + entries += Value(currentValue, countAtValue) + + + if(currentValue == bucketLimit) + iterate(index + 1, currentValue, nrOfRecordings + countAtValue, (bucketLimit << 1) + 1, increment << 1) + else + iterate(index + 1, currentValue, nrOfRecordings + countAtValue, bucketLimit, increment) + } else { + nrOfRecordings + } + } + + val nrOfRecordings = iterate(0, -1, 0, subBucketMask, 1) + + def tryUpdateTotalCount: Boolean = { + val previousTotalCount = getTotalCount + val newTotalCount = previousTotalCount - nrOfRecordings + + totalCountUpdater.compareAndSet(this, previousTotalCount, newTotalCount) + } + + while (!tryUpdateTotalCount) {} + + Snapshot(nrOfRecordings, entries.result()) + } + +} + +object AtomicSnapshotableHistogram { + val totalCountUpdater = AtomicLongFieldUpdater.newUpdater(classOf[AtomicHistogram], "totalCount") + + case class Snapshot(nrOfRecordings: Long, values: Vector[Value]) + case class Value(magnitude: Long, count: Long) +} |