| /* |
| * Copyright (C) 2022 The Android Open Source Project. |
| * |
| * Licensed 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. |
| */ |
| |
| package android.libcore; |
| |
| import android.perftests.utils.BenchmarkState; |
| import android.perftests.utils.PerfStatusReporter; |
| import android.test.suitebuilder.annotation.LargeTest; |
| |
| import androidx.test.runner.AndroidJUnit4; |
| |
| import org.junit.Rule; |
| import org.junit.Test; |
| import org.junit.runner.RunWith; |
| |
| import java.math.BigInteger; |
| import java.util.Random; |
| |
| /** |
| * This measures performance of operations on small BigIntegers. We manually determine the number of |
| * iterations so that it should cause total memory allocation on the order of a few hundred |
| * megabytes. Due to BigInteger's reliance on finalization, these may unfortunately all be kept |
| * around at once. |
| * |
| * <p>This is not structured as a proper benchmark; just run main(), e.g. with vogar |
| * libcore/benchmarks/src/benchmarks/SmallBigIntegerBenchmark.java |
| */ |
| @RunWith(AndroidJUnit4.class) |
| @LargeTest |
| public class SmallBigIntegerPerfTest { |
| @Rule public PerfStatusReporter mPerfStatusReporter = new PerfStatusReporter(); |
| // We allocate about 2 1/3 BigIntegers per iteration. |
| // Assuming 100 bytes/BigInteger, this gives us around 500MB total. |
| static final BigInteger BIG_THREE = BigInteger.valueOf(3); |
| static final BigInteger BIG_FOUR = BigInteger.valueOf(4); |
| |
| @Test |
| public void testSmallBigInteger() { |
| final Random r = new Random(); |
| BigInteger x = new BigInteger(20, r); |
| BenchmarkState state = mPerfStatusReporter.getBenchmarkState(); |
| while (state.keepRunning()) { |
| // We know this converges, but the compiler doesn't. |
| if (x.and(BigInteger.ONE).equals(BigInteger.ONE)) { |
| x = x.multiply(BIG_THREE).add(BigInteger.ONE); |
| } else { |
| x = x.shiftRight(1); |
| } |
| } |
| if (x.signum() < 0 || x.compareTo(BIG_FOUR) > 0) { |
| throw new AssertionError("Something went horribly wrong."); |
| } |
| } |
| } |