anjy7 commented on code in PR #22669: URL: https://github.com/apache/kafka/pull/22669#discussion_r3496585549
########## jmh-benchmarks/src/main/java/org/apache/kafka/jmh/raft/KRaftBenchmarkingCounters.java: ########## @@ -0,0 +1,151 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You 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 org.apache.kafka.jmh.raft; + +import org.apache.kafka.common.protocol.ApiKeys; +import org.apache.kafka.raft.RaftClientBenchmarkContext; + +import org.openjdk.jmh.annotations.AuxCounters; +import org.openjdk.jmh.annotations.Level; +import org.openjdk.jmh.annotations.Scope; +import org.openjdk.jmh.annotations.Setup; +import org.openjdk.jmh.annotations.State; +import org.openjdk.jmh.infra.BenchmarkParams; + +import java.util.Optional; + +/** + * Secondary, machine-independent work counters reported by the raft benchmarks alongside the timing + * score, as {@code benchmark:counter} rows. + * + * <p>Throughout this class, an <em>operation</em> is JMH's unit of work: a single invocation of a + * {@code @Benchmark}-annotated method. (One operation equals one invocation here because we don't use + * {@code @OperationsPerInvocation}.) JMH reports the timing score in {@code ns/op}, and these work + * counters are reported {@code PerOp} to match. + * + * <p>Each benchmark calls {@link #drainFrom} every invocation to accumulate the work deltas drained + * from {@link RaftClientBenchmarkContext}. The raw totals are private accumulators; what we report + * are the per-operation values from the {@code *PerOp()} methods (the quantity of interest), plus + * {@link #operations}. + * + * <p>JMH aggregates {@code Type.EVENTS} secondary results with {@code SUM} across all measurement + * data points i.e {@code forks x measurement iterations}. To make the <em>summary</em> row + * report the true per-operation value rather than that value multiplied by the data-point count, each + * method pre-divides by the data-point count obtained from {@link BenchmarkParams} in + * {@link #captureRunShape}. The SUM then reconstitutes the exact per-operation value (e.g. + * {@code logReadsPerOp = 1.0}) in the summary, for any {@code -f}/{@code -i} configuration. (The + * per-iteration console values are correspondingly a small fraction of the per-op value; read the + * summary row.) + * + * <p>The per-operation values are integer-exact and should be stable across a correct refactor of + * {@code KafkaRaftClient}: a flush count moving from 1 to 2 per operation is a behavioral diff, not + * measurement noise. The counters that are zero on a path (e.g. log flushes on a caught-up fetch) + * are the most useful tripwires, since zero is speed-independent. + */ +@State(Scope.Thread) +@AuxCounters(AuxCounters.Type.EVENTS) +public class KRaftBenchmarkingCounters { + private long logFlushesTotal; + private long logReadsTotal; + private long logTruncationsTotal; + private long rpcRequestsSentTotal; + private long rpcResponsesSentTotal; + private long quorumStateWritesTotal; + private long quorumStateReadsTotal; + + // Reported: the number of operations (i.e. @Benchmark method invocations) measured in the + // iteration, and the divisor for the per-operation values below. + public long operations; + + // The number of measurement data points JMH will SUM the per-op methods over, i.e. + // (forks x measurement iterations) for this run. Captured from BenchmarkParams so it tracks the + // actual run shape (including -f/-i overrides) rather than being hardcoded. + private double measurementDataPoints = 1.0; + + @Setup(Level.Trial) + public void captureRunShape(BenchmarkParams params) { + // forks() is 0 when forking is disabled (in-process), which is still one set of iterations. + int forks = Math.max(1, params.getForks()); + measurementDataPoints = (double) forks * params.getMeasurement().getCount(); + } + + @Setup(Level.Iteration) + public void reset() { + logFlushesTotal = 0; + logReadsTotal = 0; + logTruncationsTotal = 0; + rpcRequestsSentTotal = 0; + rpcResponsesSentTotal = 0; + quorumStateWritesTotal = 0; + quorumStateReadsTotal = 0; + } + + /** + * Accumulates this invocation's work deltas drained from {@code context} into these counters. + * {@code expectedRequest}/{@code expectedResponse}, if present, restrict the RPC request/response + * counts to that API key (e.g. {@code FETCH}); empty counts all. + */ + public void drainFrom( Review Comment: sure, the rename sounds good. `@TearDown` is not really suitable here because of the reasons discussed here - https://github.com/apache/kafka/pull/22669#discussion_r3484069959 Also, the docs say `@TearDown(Level.Invocation)` is unsuitable for sub-millisecond benchmarks. Our leader fetch averages at around 800ns. I think its okay to include it inside the benchmark as its a fixed cost across all benchmarks and this cost wouldn't change after the refactor. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
