cassandra-trunk/tools/stress/src/org/apache/cassandra/stress/report/TimingInterval.java
package org.apache.cassandra.stress.report;
/*
 *
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.
 *
 */

import org.HdrHistogram.Histogram;

// represents measurements taken over an interval of time
// used for both single timer results and merged timer results
public final class TimingInterval
{
    private final Histogram responseTime = new Histogram(3);
    private final Histogram serviceTime = new Histogram(3);
    private final Histogram waitTime = new Histogram(3);

    public static final long[] EMPTY_SAMPLE = new long[0];
    // nanos
    private long startNs = Long.MAX_VALUE;
    private long endNs = Long.MIN_VALUE;

    // discrete
    public long partitionCount;
    public long rowCount;
    public long errorCount;
    public final boolean isFixed;

    public TimingInterval(boolean isFixed){
        this.isFixed = isFixed;
    }

    public String toString()
    {
        return String.format("Start: %d end: %d maxLatency: %d pCount: %d rcount: %d opCount: %d errors: %d",
                             startNs, endNs, getLatencyHistogram().getMaxValue(),
                             partitionCount, rowCount, getLatencyHistogram().getTotalCount(), errorCount);
    }


    public double opRate()
    {
        return getLatencyHistogram().getTotalCount() / ((endNs - startNs) * 0.000000001d);
    }

    public double adjustedRowRate()
    {
        return rowCount / ((endNs - (startNs + getLatencyHistogram().getMaxValue())) * 0.000000001d);
    }

    public double partitionRate()
    {
        return partitionCount / ((endNs - startNs) * 0.000000001d);
    }

    public double rowRate()
    {
        return rowCount / ((endNs - startNs) * 0.000000001d);
    }

    public double meanLatencyMs()
    {
        return getLatencyHistogram().getMean() * 0.000001d;
    }

    public double maxLatencyMs()
    {
        return getLatencyHistogram().getMaxValue() * 0.000001d;
    }

    public double medianLatencyMs()
    {
        return getLatencyHistogram().getValueAtPercentile(50.0) * 0.000001d;
    }


    /**
     * @param percentile between 0.0 and 100.0
     * @return latency in milliseconds at percentile
     */
    public double latencyAtPercentileMs(double percentile)
    {
        return getLatencyHistogram().getValueAtPercentile(percentile) * 0.000001d;
    }

    public long runTimeMs()
    {
        return (endNs - startNs) / 1000000;
    }

    public long endNanos()
    {
        return endNs;
    }

    public long startNanos()
    {
        return startNs;
    }

    public Histogram responseTime()
    {
        return responseTime;
    }

    public Histogram serviceTime()
    {
        return serviceTime;
    }

    public Histogram waitTime()
    {
        return waitTime;
    }

    private Histogram getLatencyHistogram()
    {
        if (!isFixed || responseTime.getTotalCount() == 0)
            return serviceTime;
        else
            return responseTime;
    }

    public static enum TimingParameter
    {
        OPRATE, ROWRATE, ADJROWRATE, PARTITIONRATE, MEANLATENCY, MAXLATENCY, MEDIANLATENCY, RANKLATENCY,
        ERRORCOUNT, PARTITIONCOUNT
    }

    String getStringValue(TimingParameter value)
    {
        return getStringValue(value, Float.NaN);
    }

    String getStringValue(TimingParameter value, double rank)
    {
        switch (value)
        {
            case OPRATE:         return String.format("%,.0f", opRate());
            case ROWRATE:        return String.format("%,.0f", rowRate());
            case ADJROWRATE:     return String.format("%,.0f", adjustedRowRate());
            case PARTITIONRATE:  return String.format("%,.0f", partitionRate());
            case MEANLATENCY:    return String.format("%,.1f", meanLatencyMs());
            case MAXLATENCY:     return String.format("%,.1f", maxLatencyMs());
            case MEDIANLATENCY:  return String.format("%,.1f", medianLatencyMs());
            case RANKLATENCY:    return String.format("%,.1f", latencyAtPercentileMs(rank));
            case ERRORCOUNT:     return String.format("%,d", errorCount);
            case PARTITIONCOUNT: return String.format("%,d", partitionCount);
            default:             throw new IllegalStateException();
        }
    }

    public long operationCount()
    {
        return getLatencyHistogram().getTotalCount();
    }


    public void startNanos(long started)
    {
        this.startNs = started;
    }
    public void endNanos(long ended)
    {
        this.endNs = ended;
    }


    public void reset()
    {
        this.endNs = Long.MIN_VALUE;
        this.startNs = Long.MAX_VALUE;
        this.errorCount = 0;
        this.rowCount = 0;
        this.partitionCount = 0;
        if(this.responseTime.getTotalCount() != 0)
        {
            this.responseTime.reset();
        }
        if(this.serviceTime.getTotalCount() != 0)
        {
            this.serviceTime.reset();
        }
        if(this.waitTime.getTotalCount() != 0)
        {
            this.waitTime.reset();
        }
    }

    public void add(TimingInterval value)
    {
        if(this.startNs > value.startNs)
        {
            this.startNs = value.startNs;
        }
        if(this.endNs < value.endNs)
        {
            this.endNs = value.endNs;
        }

        this.errorCount += value.errorCount;
        this.rowCount += value.rowCount;
        this.partitionCount += value.partitionCount;

        if (value.responseTime.getTotalCount() != 0)
        {
            this.responseTime.add(value.responseTime);
        }
        if (value.serviceTime.getTotalCount() != 0)
        {
            this.serviceTime.add(value.serviceTime);
        }
        if (value.waitTime.getTotalCount() != 0)
        {
            this.waitTime.add(value.waitTime);
        }
    }
 }

