jdk-24/test/micro/org/openjdk/bench/java/lang/StringIndexOfChar.java

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 * This code is distributed in the hope that it will be useful, but WITHOUT
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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
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package org.openjdk.bench.java.lang;

import java.util.Random;
import org.openjdk.jmh.annotations.Benchmark;
import org.openjdk.jmh.annotations.BenchmarkMode;
import org.openjdk.jmh.annotations.Fork;
import org.openjdk.jmh.annotations.Measurement;
import org.openjdk.jmh.annotations.Param;
import org.openjdk.jmh.annotations.OutputTimeUnit;
import org.openjdk.jmh.annotations.Mode;
import org.openjdk.jmh.annotations.Setup;
import org.openjdk.jmh.annotations.Scope;
import org.openjdk.jmh.annotations.State;
import org.openjdk.jmh.annotations.Warmup;
import org.openjdk.jmh.infra.Blackhole;

import java.util.concurrent.TimeUnit;

/**
 * This benchmark can be used to measure performance between StringLatin1 and StringUTF16 in terms of
 * performance of the indexOf(char) and indexOf(String) methods which are intrinsified.
 * On x86 the behaviour of the indexOf method is contingent upon the length of the string
 */
@BenchmarkMode(Mode.AverageTime)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
@State(Scope.Thread)
@Warmup(iterations = 5, time = 1)
@Measurement(iterations = 5, time = 1)
@Fork(value = 1)
public class StringIndexOfChar {
    @Param("100000")
    private int loops;

    @Param("1000")
    private int pathCnt;

    @Param("1999")
    private int rngSeed;

    private Random rng;
    private String[] latn1_short;
    private String[] latn1_sse4;
    private String[] latn1_avx2;
    private String[] latn1_mixedLength;
    private String[] utf16_short;
    private String[] utf16_sse4;
    private String[] utf16_avx2;
    private String[] utf16_mixedLength;

    @Setup
    public void setup() {
        rng = new Random(rngSeed);
        latn1_short        = new String[pathCnt];
        latn1_sse4         = new String[pathCnt];
        latn1_avx2         = new String[pathCnt];
        latn1_mixedLength  = new String[pathCnt];
        utf16_short        = new String[pathCnt];
        utf16_sse4         = new String[pathCnt];
        utf16_avx2         = new String[pathCnt];
        utf16_mixedLength  = new String[pathCnt];

        for (int i = 0; i < pathCnt; i++) {
            latn1_short[i] = makeRndString(false, 15);
            latn1_sse4[i]  = makeRndString(false, 16);
            latn1_avx2[i]  = makeRndString(false, 32);
            utf16_short[i] = makeRndString(true, 7);
            utf16_sse4[i]  = makeRndString(true, 8);
            utf16_avx2[i]  = makeRndString(true, 16);
            latn1_mixedLength[i] = makeRndString(false, rng.nextInt(65));
            utf16_mixedLength[i] = makeRndString(true, rng.nextInt(65));
        }
    }

    private String makeRndString(boolean isUtf16, int length) {
        StringBuilder sb = new StringBuilder(length);
        if(length > 0){
            sb.append(isUtf16?'\u2026':'b'); // ...

            for (int i = 1; i < length-1; i++) {
                sb.append((char)('b' + rng.nextInt(26)));
            }

            sb.append(rng.nextInt(3) >= 1?'a':'b');//66.6% of time 'a' is in string
        }
        return sb.toString();
    }


    @Benchmark
    public void latin1_mixed_char(Blackhole bh) {
        for (String what : latn1_mixedLength) {
            bh.consume(what.indexOf('a'));
        }
    }

    @Benchmark
    public void utf16_mixed_char(Blackhole bh) {
        for (String what : utf16_mixedLength) {
            bh.consume(what.indexOf('a'));
        }
    }

    @Benchmark
    public void latin1_mixed_String(Blackhole bh) {
        for (String what : latn1_mixedLength) {
            bh.consume(what.indexOf("a"));
        }
    }

    @Benchmark
    public void utf16_mixed_String(Blackhole bh) {
        for (String what : utf16_mixedLength) {
            bh.consume(what.indexOf("a"));
        }
    }

    ////////// more detailed code path dependent tests //////////

    @Benchmark
    public void latin1_Short_char(Blackhole bh) {
        for (String what : latn1_short) {
            bh.consume(what.indexOf('a'));
        }
    }

    @Benchmark
    public void latin1_SSE4_char(Blackhole bh) {
        for (String what : latn1_sse4) {
            bh.consume(what.indexOf('a'));
        }
    }

    @Benchmark
    public void latin1_AVX2_char(Blackhole bh) {
        for (String what : latn1_avx2) {
            bh.consume(what.indexOf('a'));
        }
    }

    @Benchmark
    public void utf16_Short_char(Blackhole bh) {
        for (String what : utf16_short) {
            bh.consume(what.indexOf('a'));
        }
    }

    @Benchmark
    public void utf16_SSE4_char(Blackhole bh) {
        for (String what : utf16_sse4) {
            bh.consume(what.indexOf('a'));
        }
    }

    @Benchmark
    public void utf16_AVX2_char(Blackhole bh) {
        for (String what : utf16_avx2) {
            bh.consume(what.indexOf('a'));
        }
    }

    @Benchmark
    public void latin1_Short_String(Blackhole bh) {
        for (String what : latn1_short) {
            bh.consume(what.indexOf("a"));
        }
    }

    @Benchmark
    public void latin1_SSE4_String(Blackhole bh) {
        for (String what : latn1_sse4) {
            bh.consume(what.indexOf("a"));
        }
    }

    @Benchmark
    public void latin1_AVX2_String(Blackhole bh) {
        for (String what : latn1_avx2) {
            bh.consume(what.indexOf("a"));
        }
    }

    @Benchmark
    public void utf16_Short_String(Blackhole bh) {
        for (String what : utf16_short) {
            bh.consume(what.indexOf("a"));
        }
    }

    @Benchmark
    public void utf16_SSE4_String(Blackhole bh) {
        for (String what : utf16_sse4) {
            bh.consume(what.indexOf("a"));
        }
    }

    @Benchmark
    public void utf16_AVX2_String(Blackhole bh) {
        for (String what : utf16_avx2) {
            bh.consume(what.indexOf("a"));
        }
    }
}