org.eclipse.tracecompass.analysis.os.linux.core/src/org/eclipse/tracecompass/analysis/os/linux/core/cpuusage/KernelCpuUsageStateProvider.java

   1 /*******************************************************************************
   2  * Copyright (c) 2014, 2015 École Polytechnique de Montréal
   3  *
   4  * All rights reserved. This program and the accompanying materials are
   5  * made available under the terms of the Eclipse Public License v1.0 which
   6  * accompanies this distribution, and is available at
   7  * http://www.eclipse.org/legal/epl-v10.html
   8  *
   9  * Contributors:
  10  *   François Rajotte - Initial API and implementation
  11  *   Geneviève Bastien - Revision of the initial implementation
  12  *******************************************************************************/
  13
  14 package org.eclipse.tracecompass.analysis.os.linux.core.cpuusage;
  15
  16 import static org.eclipse.tracecompass.common.core.NonNullUtils.checkNotNull;
  17
  18 import java.util.HashMap;
  19 import java.util.Map;
  20
  21 import org.eclipse.jdt.annotation.Nullable;
  22 import org.eclipse.tracecompass.analysis.os.linux.core.kernelanalysis.Attributes;
  23 import org.eclipse.tracecompass.analysis.os.linux.core.trace.IKernelAnalysisEventLayout;
  24 import org.eclipse.tracecompass.internal.analysis.os.linux.core.Activator;
  25 import org.eclipse.tracecompass.statesystem.core.ITmfStateSystemBuilder;
  26 import org.eclipse.tracecompass.statesystem.core.exceptions.AttributeNotFoundException;
  27 import org.eclipse.tracecompass.statesystem.core.statevalue.ITmfStateValue;
  28 import org.eclipse.tracecompass.statesystem.core.statevalue.TmfStateValue;
  29 import org.eclipse.tracecompass.tmf.core.event.ITmfEvent;
  30 import org.eclipse.tracecompass.tmf.core.event.ITmfEventField;
  31 import org.eclipse.tracecompass.tmf.core.event.aspect.TmfCpuAspect;
  32 import org.eclipse.tracecompass.tmf.core.statesystem.AbstractTmfStateProvider;
  33 import org.eclipse.tracecompass.tmf.core.trace.ITmfTrace;
  34 import org.eclipse.tracecompass.tmf.core.trace.TmfTraceUtils;
  35
  36 /**
  37  * Creates a state system with the total time spent on CPU for each thread and
  38  * for each CPU from a kernel trace.
  39  *
  40  * This state system in itself keeps the total time on CPU since last time the
  41  * process was scheduled out. The state system queries will only be accurate
  42  * when the process is not in a running state. To have exact CPU usage when
  43  * running, this state system needs to be used along the LTTng Kernel analysis.
  44  *
  45  * It requires only the 'sched_switch' events enabled on the trace.
  46  *
  47  * @author François Rajotte
  48  */
  49 public class KernelCpuUsageStateProvider extends AbstractTmfStateProvider {
  50
  51     private static final int VERSION = 2;
  52
  53     /* For each CPU, maps the last time a thread was scheduled in */
  54     private final Map<Integer, Long> fLastStartTimes = new HashMap<>();
  55     private final long fTraceStart;
  56     private final IKernelAnalysisEventLayout fLayout;
  57
  58     /**
  59      * Constructor
  60      *
  61      * @param trace
  62      *            The trace from which to get the CPU usage
  63      * @param layout
  64      *            The event layout to use for this state provider.
  65      */
  66     public KernelCpuUsageStateProvider(ITmfTrace trace, IKernelAnalysisEventLayout layout) {
  67         super(trace, "Kernel CPU usage"); //$NON-NLS-1$
  68         fTraceStart = trace.getStartTime().getValue();
  69         fLayout = layout;
  70     }
  71
  72     // ------------------------------------------------------------------------
  73     // ITmfStateProvider
  74     // ------------------------------------------------------------------------
  75
  76     @Override
  77     public int getVersion() {
  78         return VERSION;
  79     }
  80
  81     @Override
  82     public KernelCpuUsageStateProvider getNewInstance() {
  83         return new KernelCpuUsageStateProvider(this.getTrace(), this.fLayout);
  84     }
  85
  86     @Override
  87     protected void eventHandle(@Nullable ITmfEvent event) {
  88         if (event == null) {
  89             return;
  90         }
  91         final String eventName = event.getName();
  92
  93         if (eventName.equals(fLayout.eventSchedSwitch())) {
  94             Object cpuObj = TmfTraceUtils.resolveEventAspectOfClassForEvent(event.getTrace(), TmfCpuAspect.class, event);
  95             if (cpuObj == null) {
  96                 /* We couldn't find any CPU information, ignore this event */
  97                 return;
  98             }
  99             Integer cpu = (Integer) cpuObj;
 100
 101             /*
 102              * Fields: string prev_comm, int32 prev_tid, int32 prev_prio, int64
 103              * prev_state, string next_comm, int32 next_tid, int32 next_prio
 104              */
 105             ITmfEventField content = event.getContent();
 106             long ts = event.getTimestamp().getValue();
 107
 108             Long prevTid = (Long) content.getField(fLayout.fieldPrevTid()).getValue();
 109
 110             try {
 111                 final ITmfStateSystemBuilder ss = checkNotNull(getStateSystemBuilder());
 112
 113                 Integer currentCPUNode = ss.getQuarkRelativeAndAdd(getNodeCPUs(ss), cpu.toString());
 114
 115                 /*
 116                  * This quark contains the value of the cumulative time spent on
 117                  * the source CPU by the currently running thread
 118                  */
 119                 Integer cumulativeTimeQuark = ss.getQuarkRelativeAndAdd(currentCPUNode, prevTid.toString());
 120                 Long startTime = fLastStartTimes.get(cpu);
 121                 /*
 122                  * If start time is null, we haven't seen the start of the
 123                  * process, so we assume beginning of the trace
 124                  */
 125                 if (startTime == null) {
 126                     startTime = fTraceStart;
 127                 }
 128
 129                 /*
 130                  * We add the time from startTime until now to the cumulative
 131                  * time of the thread
 132                  */
 133                 ITmfStateValue value = ss.queryOngoingState(cumulativeTimeQuark);
 134
 135                 /*
 136                  * Modify cumulative time for this CPU/TID combo: The total time
 137                  * changes when the process is scheduled out. Nothing happens
 138                  * when the process is scheduled in.
 139                  */
 140                 long prevCumulativeTime = Math.max(0, value.unboxLong());
 141                 long newCumulativeTime = prevCumulativeTime + (ts - startTime);
 142
 143                 value = TmfStateValue.newValueLong(newCumulativeTime);
 144                 ss.modifyAttribute(ts, value, cumulativeTimeQuark);
 145                 fLastStartTimes.put(cpu, ts);
 146
 147             } catch (AttributeNotFoundException e) {
 148                 Activator.getDefault().logError("Attribute not found in LttngKernelCpuStateProvider", e); //$NON-NLS-1$
 149             }
 150
 151         }
 152     }
 153
 154     /* Shortcut for the "current CPU" attribute node */
 155     private static int getNodeCPUs(ITmfStateSystemBuilder ssb) {
 156         return ssb.getQuarkAbsoluteAndAdd(Attributes.CPUS);
 157     }
 158
 159 }