TranslationLookasideBuffer.java

/**
 * ****************************************************************************
 * Copyright (c) 2010-2016 by Min Cai (min.cai.china@gmail.com).
 * <p>
 * This file is part of the Archimulator multicore architectural simulator.
 * <p>
 * Archimulator is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * <p>
 * Archimulator is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * <p>
 * You should have received a copy of the GNU General Public License
 * along with Archimulator. If not, see <http://www.gnu.org/licenses/>.
 * ****************************************************************************
 */
package archimulator.uncore.tlb;

import archimulator.common.CPUExperiment;
import archimulator.common.Named;
import archimulator.common.Simulation;
import archimulator.common.SimulationObject;
import archimulator.common.report.ReportNode;
import archimulator.common.report.Reportable;
import archimulator.uncore.MemoryHierarchyAccess;
import archimulator.uncore.cache.*;
import archimulator.uncore.cache.replacement.CacheReplacementPolicyType;
import archimulator.util.ValueProvider;

/**
 * Translation lookaside buffer (TLB).
 *
 * @author Min Cai
 */
public class TranslationLookasideBuffer implements Named, Reportable {
    private String name;

    private EvictableCache<Boolean> cache;

    private long numHits;
    private long numMisses;

    private long numEvictions;

    /**
     * Create a translation lookaside buffer (TLB).
     *
     * @param parent the parent simulation object
     * @param name   the name
     */
    public TranslationLookasideBuffer(SimulationObject<CPUExperiment, Simulation> parent, String name) {
        this.name = name;

        this.cache = new BasicEvictableCache<>(
                parent,
                name,
                new CacheGeometry(
                        parent.getExperiment().getConfig().getTlbSize(),
                        parent.getExperiment().getConfig().getTlbAssociativity(),
                        parent.getExperiment().getConfig().getTlbLineSize()
                ),
                CacheReplacementPolicyType.LRU,
                args -> new BooleanValueProvider()
        );
    }

    /**
     * Act on a TLB access.
     *
     * @param access              the memory hierarchy access
     * @param onCompletedCallback the callback action performed when the access is completed
     */
    public void access(MemoryHierarchyAccess access, Runnable onCompletedCallback) {
        int set = this.cache.getSet(access.getPhysicalAddress());
        CacheAccess<Boolean> cacheAccess = this.cache.newAccess(access, access.getPhysicalAddress());

        if (cacheAccess.isHitInCache()) {
            getCache().getReplacementPolicy().handlePromotionOnHit(access, set, cacheAccess.getWay());

            this.numHits++;
        } else {
            if (cacheAccess.isReplacement()) {
                this.numEvictions++;
            }

            CacheLine<Boolean> line = this.cache.getLine(set, cacheAccess.getWay());
            BooleanValueProvider stateProvider = (BooleanValueProvider) line.getStateProvider();
            stateProvider.state = true;
            line.setAccess(access);
            line.setTag(access.getPhysicalTag());
            getCache().getReplacementPolicy().handleInsertionOnMiss(access, set, cacheAccess.getWay());

            this.numMisses++;
        }

        access.getThread().getCycleAccurateEventQueue().schedule(this, onCompletedCallback, cacheAccess.isHitInCache() ? this.getHitLatency() : this.getMissLatency());
    }

    @Override
    public void dumpStats(ReportNode reportNode) {
        reportNode.getChildren().add(new ReportNode(reportNode, getName()) {{
            getChildren().add(new ReportNode(this, "hitRatio", getHitRatio() + ""));
            getChildren().add(new ReportNode(this, "numAccesses", getNumAccesses() + ""));
            getChildren().add(new ReportNode(this, "numHits", getNumHits() + ""));
            getChildren().add(new ReportNode(this, "numMisses", getNumMisses() + ""));
            getChildren().add(new ReportNode(this, "numEvictions", getNumEvictions() + ""));
        }});
    }

    /**
     * Get the name of the translation lookaside buffer (TLB).
     *
     * @return the name of the translation lookaside buffer (TLB)
     */
    public String getName() {
        return name;
    }

    /**
     * Get the number of misses.
     *
     * @return the number of misses
     */
    public long getNumMisses() {
        return this.numMisses;
    }

    /**
     * Get the number of hits.
     *
     * @return the number of hits
     */
    public long getNumHits() {
        return numHits;
    }

    /**
     * Get the number of accesses.
     *
     * @return the number of accesses
     */
    public long getNumAccesses() {
        return numHits + numMisses;
    }

    /**
     * Get the hit ratio.
     *
     * @return the hit ratio
     */
    public double getHitRatio() {
        return this.getNumAccesses() > 0 ? (double) this.numHits / this.getNumAccesses() : 0.0;
    }

    /**
     * Get the number of evictions.
     *
     * @return the number of evictions
     */
    public long getNumEvictions() {
        return numEvictions;
    }

    /**
     * Get the occupancy ratio.
     *
     * @return the occupancy ratio
     */
    public double getOccupancyRatio() {
        return getCache().getOccupancyRatio();
    }

    /**
     * Get the hit latency.
     *
     * @return the hit latency
     */
    public int getHitLatency() {
        return getCache().getExperiment().getConfig().getTlbHitLatency();
    }

    /**
     * Get the miss latency.
     *
     * @return the miss latency
     */
    public int getMissLatency() {
        return getCache().getExperiment().getConfig().getTlbMissLatency();
    }

    /**
     * Get the owned evictable cache.
     *
     * @return the owned evictable cache
     */
    public EvictableCache<Boolean> getCache() {
        return cache;
    }

    /**
     * Boolean value provider.
     */
    private class BooleanValueProvider implements ValueProvider<Boolean> {
        protected boolean state;

        /**
         * Create a boolean value provider.
         */
        public BooleanValueProvider() {
            this.state = false;
        }

        /**
         * Get the value.
         *
         * @return the value
         */
        @Override
        public Boolean get() {
            return state;
        }

        /**
         * Get the initial value.
         *
         * @return the initial value
         */
        @Override
        public Boolean getInitialValue() {
            return false;
        }
    }
}