1 /* 2 * Copyright (C) 2013 The Guava Authors 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.google.common.base; 18 19 import static com.google.common.base.Throwables.lazyStackTrace; 20 import static java.util.Arrays.asList; 21 22 import com.google.caliper.BeforeExperiment; 23 import com.google.caliper.Benchmark; 24 import com.google.caliper.Param; 25 import com.google.caliper.api.SkipThisScenarioException; 26 import java.util.List; 27 28 /** 29 * Quick and dirty benchmark of {@link Throwables#lazyStackTrace(Throwable)}. We benchmark a "caller 30 * finder" implementation that might be used in a logging framework. 31 */ 32 public class LazyStackTraceBenchmark { 33 @Param({"20", "200", "2000"}) 34 int stackDepth; 35 36 @Param({"-1", "3", "15"}) 37 int breakAt; 38 39 int recursionCount; 40 41 private static final Object duh = new Object(); 42 43 @Param Mode mode; 44 45 enum Mode { 46 LAZY_STACK_TRACE { 47 @Override getStackTrace(Throwable t)48 List<StackTraceElement> getStackTrace(Throwable t) { 49 return lazyStackTrace(t); 50 } 51 }, 52 GET_STACK_TRACE { 53 @Override getStackTrace(Throwable t)54 List<StackTraceElement> getStackTrace(Throwable t) { 55 return asList(t.getStackTrace()); 56 } 57 }; 58 timeIt(int reps, int breakAt)59 boolean timeIt(int reps, int breakAt) { 60 boolean dummy = false; 61 for (int i = 0; i < reps; i++) { 62 int f = 0; 63 Throwable t = new Throwable(); 64 for (StackTraceElement ste : getStackTrace(t)) { 65 dummy |= ste == duh; 66 if (f++ == breakAt) { 67 break; 68 } 69 } 70 } 71 return dummy; 72 } 73 getStackTrace(Throwable t)74 abstract List<StackTraceElement> getStackTrace(Throwable t); 75 } 76 77 @BeforeExperiment doBefore()78 public void doBefore() { 79 recursionCount = stackDepth - new Throwable().getStackTrace().length - 1; 80 if (recursionCount < 0) { 81 throw new SkipThisScenarioException(); 82 } 83 } 84 85 @Benchmark timeFindCaller(int reps)86 public boolean timeFindCaller(int reps) { 87 return timeFindCaller(reps, recursionCount); 88 } 89 timeFindCaller(int reps, int recurse)90 private boolean timeFindCaller(int reps, int recurse) { 91 return recurse > 0 ? timeFindCaller(reps, recurse - 1) : mode.timeIt(reps, breakAt); 92 } 93 } 94