analysis/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.kernel.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.StateSystemBuilderUtils;
  27 import org.eclipse.tracecompass.statesystem.core.exceptions.AttributeNotFoundException;
  28 import org.eclipse.tracecompass.tmf.core.event.ITmfEvent;
  29 import org.eclipse.tracecompass.tmf.core.event.ITmfEventField;
  30 import org.eclipse.tracecompass.tmf.core.event.aspect.TmfCpuAspect;
  31 import org.eclipse.tracecompass.tmf.core.statesystem.AbstractTmfStateProvider;
  32 import org.eclipse.tracecompass.tmf.core.trace.ITmfTrace;
  33 import org.eclipse.tracecompass.tmf.core.trace.TmfTraceUtils;
  34
  35 /**
  36  * Creates a state system with the total time spent on CPU for each thread and
  37  * for each CPU from a kernel trace.
  38  *
  39  * This state system in itself keeps the total time on CPU since last time the
  40  * process was scheduled out. The state system queries will only be accurate
  41  * when the process is not in a running state. To have exact CPU usage when
  42  * running, this state system needs to be used along the LTTng Kernel analysis.
  43  *
  44  * It requires only the 'sched_switch' events enabled on the trace.
  45  *
  46  * @author François Rajotte
  47  */
  48 public class KernelCpuUsageStateProvider extends AbstractTmfStateProvider {
  49
  50     private static final int VERSION = 2;
  51
  52     /* For each CPU, maps the last time a thread was scheduled in */
  53     private final Map<Integer, Long> fLastStartTimes = new HashMap<>();
  54     private final long fTraceStart;
  55     private final IKernelAnalysisEventLayout fLayout;
  56
  57     /**
  58      * Constructor
  59      *
  60      * @param trace
  61      *            The trace from which to get the CPU usage
  62      * @param layout
  63      *            The event layout to use for this state provider.
  64      */
  65     public KernelCpuUsageStateProvider(ITmfTrace trace, IKernelAnalysisEventLayout layout) {
  66         super(trace, "Kernel CPU usage"); //$NON-NLS-1$
  67         fTraceStart = trace.getStartTime().getValue();
  68         fLayout = layout;
  69     }
  70
  71     // ------------------------------------------------------------------------
  72     // ITmfStateProvider
  73     // ------------------------------------------------------------------------
  74
  75     @Override
  76     public int getVersion() {
  77         return VERSION;
  78     }
  79
  80     @Override
  81     public KernelCpuUsageStateProvider getNewInstance() {
  82         return new KernelCpuUsageStateProvider(this.getTrace(), this.fLayout);
  83     }
  84
  85     @Override
  86     protected void eventHandle(@Nullable ITmfEvent event) {
  87         if (event == null) {
  88             return;
  89         }
  90         final String eventName = event.getName();
  91
  92         if (eventName.equals(fLayout.eventSchedSwitch())) {
  93             Integer cpu = TmfTraceUtils.resolveIntEventAspectOfClassForEvent(event.getTrace(), TmfCpuAspect.class, event);
  94             if (cpu == null) {
  95                 /* We couldn't find any CPU information, ignore this event */
  96                 return;
  97             }
  98
  99             /*
 100              * Fields: string prev_comm, int32 prev_tid, int32 prev_prio, int64
 101              * prev_state, string next_comm, int32 next_tid, int32 next_prio
 102              */
 103             ITmfEventField content = event.getContent();
 104             long ts = event.getTimestamp().getValue();
 105
 106             Long prevTid = (Long) content.getField(fLayout.fieldPrevTid()).getValue();
 107
 108             try {
 109                 final ITmfStateSystemBuilder ss = checkNotNull(getStateSystemBuilder());
 110
 111                 Integer currentCPUNode = ss.getQuarkRelativeAndAdd(getNodeCPUs(ss), cpu.toString());
 112
 113                 /*
 114                  * This quark contains the value of the cumulative time spent on
 115                  * the source CPU by the currently running thread
 116                  */
 117                 Integer cumulativeTimeQuark = ss.getQuarkRelativeAndAdd(currentCPUNode, prevTid.toString());
 118                 Long startTime = fLastStartTimes.get(cpu);
 119                 /*
 120                  * If start time is null, we haven't seen the start of the
 121                  * process, so we assume beginning of the trace
 122                  */
 123                 if (startTime == null) {
 124                     startTime = fTraceStart;
 125                 }
 126
 127                 /*
 128                  * Modify cumulative time for this CPU/TID combo: The total time
 129                  * changes when the process is scheduled out. Nothing happens
 130                  * when the process is scheduled in.
 131                  */
 132                 StateSystemBuilderUtils.incrementAttributeLong(ss, ts, cumulativeTimeQuark, ts - startTime);
 133
 134                 fLastStartTimes.put(cpu, ts);
 135
 136             } catch (AttributeNotFoundException e) {
 137                 Activator.getDefault().logError("Attribute not found in LttngKernelCpuStateProvider", e); //$NON-NLS-1$
 138             }
 139
 140         }
 141     }
 142
 143     /* Shortcut for the "current CPU" attribute node */
 144     private static int getNodeCPUs(ITmfStateSystemBuilder ssb) {
 145         return ssb.getQuarkAbsoluteAndAdd(Attributes.CPUS);
 146     }
 147
 148 }