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/*
* =========================================================================================
* Copyright © 2013-2015 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 kamon.system.custom
import java.io.IOException
import java.nio.charset.StandardCharsets
import java.nio.file.{ Paths, Files }
import akka.actor.{ Props, Actor, ActorSystem }
import akka.event.{ Logging, LoggingAdapter }
import kamon.Kamon
import kamon.metric._
import kamon.metric.instrument.InstrumentFactory
import kamon.system.custom.ContextSwitchesUpdater.UpdateContextSwitches
import org.hyperic.sigar.Sigar
import scala.collection.JavaConverters.iterableAsScalaIterableConverter
import scala.concurrent.duration.FiniteDuration
/**
* Context Switches metrics:
* - process-voluntary: Total number of voluntary context switches related to the current process (one thread explicitly yield the CPU to another).
* - process-non-voluntary: Total number of involuntary context switches related to the current process (the system scheduler suspends and active thread, and switches control to a different thread).
* - global: Total number of context switches across all CPUs.
*/
class ContextSwitchesMetrics(pid: Long, log: LoggingAdapter, instrumentFactory: InstrumentFactory) extends GenericEntityRecorder(instrumentFactory) {
val perProcessVoluntary = histogram("context-switches-process-voluntary")
val perProcessNonVoluntary = histogram("context-switches-process-non-voluntary")
val global = histogram("context-switches-global")
def update(): Unit = {
def contextSwitchesByProcess(pid: Long): (Long, Long) = {
val filename = s"/proc/$pid/status"
var voluntaryContextSwitches = 0L
var nonVoluntaryContextSwitches = 0L
try {
for (line ← Files.readAllLines(Paths.get(filename), StandardCharsets.US_ASCII).asScala.toList) {
if (line.startsWith("voluntary_ctxt_switches")) {
voluntaryContextSwitches = line.substring(line.indexOf(":") + 1).trim.toLong
}
if (line.startsWith("nonvoluntary_ctxt_switches")) {
nonVoluntaryContextSwitches = line.substring(line.indexOf(":") + 1).trim.toLong
}
}
} catch {
case ex: IOException ⇒ log.error("Error trying to read [{}]", filename)
}
(voluntaryContextSwitches, nonVoluntaryContextSwitches)
}
def contextSwitches: Long = {
val filename = "/proc/stat"
var contextSwitches = 0L
try {
for (line ← Files.readAllLines(Paths.get(filename), StandardCharsets.US_ASCII).asScala.toList) {
if (line.startsWith("ctxt")) {
contextSwitches = line.substring(line.indexOf(" ") + 1).toLong
}
}
} catch {
case ex: IOException ⇒ log.error("Error trying to read [{}]", filename)
}
contextSwitches
}
val (voluntary, nonVoluntary) = contextSwitchesByProcess(pid)
perProcessVoluntary.record(voluntary)
perProcessNonVoluntary.record(nonVoluntary)
global.record(contextSwitches)
}
}
object ContextSwitchesMetrics {
def register(system: ActorSystem, refreshInterval: FiniteDuration): ContextSwitchesMetrics = {
val log = Logging(system, "ContextSwitchesMetrics")
val pid = (new Sigar).getPid
Kamon.metrics.entity(EntityRecorderFactory("system-metric", new ContextSwitchesMetrics(pid, log, _)), "context-switches")
}
}
class ContextSwitchesUpdater(csm: ContextSwitchesMetrics, refreshInterval: FiniteDuration) extends Actor {
val schedule = context.system.scheduler.schedule(refreshInterval, refreshInterval, self, UpdateContextSwitches)(context.dispatcher)
def receive = {
case UpdateContextSwitches ⇒ csm.update()
}
override def postStop(): Unit = {
schedule.cancel()
super.postStop()
}
}
object ContextSwitchesUpdater {
case object UpdateContextSwitches
def props(csm: ContextSwitchesMetrics, refreshInterval: FiniteDuration): Props =
Props(new ContextSwitchesUpdater(csm, refreshInterval))
}
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