package org.openjdk.gcbench.fragger;

import org.openjdk.gcbench.tests.Sequence;
import org.openjdk.jmh.annotations.*;
import org.openjdk.jmh.profile.SafepointsProfiler;
import org.openjdk.jmh.results.Result;
import org.openjdk.jmh.results.RunResult;
import org.openjdk.jmh.runner.Runner;
import org.openjdk.jmh.runner.RunnerException;
import org.openjdk.jmh.runner.options.Options;
import org.openjdk.jmh.runner.options.OptionsBuilder;
import org.openjdk.jmh.runner.options.TimeValue;
import org.openjdk.jmh.runner.options.VerboseMode;

import java.io.PrintStream;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.concurrent.ThreadLocalRandom;
import java.util.concurrent.TimeUnit;


@Warmup(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS)
@Measurement(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS)
@Fork(value = 1)
@BenchmarkMode(Mode.AverageTime)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
@Threads(1)
@State(Scope.Benchmark)
public class LRUFragger {

    static final int PAYLOAD_SIZE = 4096;

    @Param({"1000"})
    int size;

    Map<Object, Object> cache;
    int keyCount;

    @Setup
    public void setup() {
        cache = new LinkedHashMap<Object, Object>(size*4/3, 0.75f, true) {
            @Override
            protected boolean removeEldestEntry(Map.Entry<Object, Object> eldest) {
                return size() > size;
            }
        };
        keyCount = (int) (size * (1D / 0.8D)); // 80% hit rate
        for (int c = 0; c < size; c++) {
            cache.put("Key " + c, new byte[PAYLOAD_SIZE]);
        }
    }

    @Benchmark
    public Object test() {
        int idx = ThreadLocalRandom.current().nextInt(keyCount);
        Object k = "Key " + idx;
        Object o = cache.get(k);
        if (o == null) {
            o = new byte[PAYLOAD_SIZE];
            cache.put(k, o);
        }
        return o;
    }

    public static void main(String... args) throws RunnerException {
        Options parent = new OptionsBuilder()
                .detectJvmArgs()
                .jvmArgsAppend("-Xmx100g", "-Xms100g", "-XX:MaxGCPauseMillis=10", "-XX:+AlwaysPreTouch")
                .include(LRUFragger.class.getCanonicalName())
                .verbosity(VerboseMode.SILENT)
                .addProfiler(SafepointsProfiler.class)
                .warmupIterations(5)
                .warmupTime(TimeValue.seconds(10))
                .measurementIterations(5)
                .measurementTime(TimeValue.seconds(1))
                .measurementTime(TimeValue.seconds(10))
                .build();

        PrintStream pw = System.out;

        Sequence sizeSeq = Sequence.steps(0, 23_000_000, 10);

        for (String gc : new String[]{"-XX:+UseParallelOldGC", "-XX:+UseG1GC", "-XX:+UseConcMarkSweepGC", "-XX:+UseShenandoahGC"}) {
            for (Object size : sizeSeq) {
                if (size.toString().equals("0")) continue;

                Options opt = new OptionsBuilder()
                        .parent(parent)
                        .jvmArgsPrepend(gc)
                        .param("size", size.toString())
                        .build();

                try {
                    RunResult res = new Runner(opt).runSingle();
                    Result pr = res.getPrimaryResult();
                    Map<String, Result> sec = res.getSecondaryResults();

                    pw.printf("%10s, %30s,      %10.3f, %10.3f,     %5.0f, %10.3f,     %10.3f, %10.3f,       %10.3f, %10.3f, %10.3f, %10.3f, %10.3f, %10.3f, %10.3f, %10.3f%n",
                            size.toString(),
                            gc,

                            pr.getScore(),
                            pr.getScoreError(),

                            sec.get("·safepoints.pause.count").getScore(),
                            sec.get("·safepoints.pause").getScore(),

                            sec.get("·safepoints.interval").getScore(),
                            sec.get("·safepoints.pause.avg").getScore(),

                            sec.get("·safepoints.pause.p0.00").getScore(),
                            sec.get("·safepoints.pause.p0.50").getScore(),
                            sec.get("·safepoints.pause.p0.90").getScore(),
                            sec.get("·safepoints.pause.p0.95").getScore(),
                            sec.get("·safepoints.pause.p0.99").getScore(),
                            sec.get("·safepoints.pause.p0.999").getScore(),
                            sec.get("·safepoints.pause.p0.9999").getScore(),
                            sec.get("·safepoints.pause.p1.00").getScore()
                    );
                } catch (RunnerException e) {
                    // okay
                }
            }
        }
    }


}