src-kafka/checkstyle/import-control-jmh-benchmar...

<!DOCTYPE import-control PUBLIC
        "-//Puppy Crawl//DTD Import Control 1.1//EN"
        "http://www.puppycrawl.com/dtds/import_control_1_1.dtd">
<!--
// 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
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// 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
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<import-control pkg="org.apache.kafka.jmh">

    <allow pkg="java"/>
    <allow pkg="scala"/>
    <allow pkg="javax.management"/>
    <allow pkg="org.slf4j"/>
    <allow pkg="org.openjdk.jmh.annotations"/>
    <allow pkg="org.openjdk.jmh.runner"/>
    <allow pkg="org.openjdk.jmh.infra"/>
    <allow pkg="java.security"/>
    <allow pkg="javax.net.ssl"/>
    <allow pkg="javax.security"/>
    <allow pkg="org.apache.kafka.common"/>
    <allow pkg="org.apache.kafka.clients.producer"/>
    <allow pkg="kafka.cluster"/>
    <allow pkg="kafka.log"/>
    <allow pkg="kafka.server"/>
    <allow pkg="kafka.api"/>
    <allow class="kafka.utils.KafkaScheduler"/>
    <allow pkg="org.mockito"/>


    <subpackage name="cache">
    </subpackage>
</import-control>
KAFKA-8841; Reduce overhead of ReplicaManager.updateFollowerFetchState (#7324) This PR makes two changes to code in the ReplicaManager.updateFollowerFetchState path, which is in the hot path for follower fetches. Although calling ReplicaManager.updateFollowerFetch state is inexpensive on its own, it is called once for each partition every time a follower fetch occurs. 1. updateFollowerFetchState no longer calls maybeExpandIsr when the follower is already in the ISR. This avoid repeated expansion checks. 2. Partition.maybeIncrementLeaderHW is also in the hot path for ReplicaManager.updateFollowerFetchState. Partition.maybeIncrementLeaderHW calls Partition.remoteReplicas four times each iteration, and it performs a toSet conversion. maybeIncrementLeaderHW now avoids generating any intermediate collections when updating the HWM. Benchmark results for Partition.updateFollowerFetchState on a r5.xlarge: Old: ``` 1288.633 ±(99.9%) 1.170 ns/op [Average] (min, avg, max) = (1287.343, 1288.633, 1290.398), stdev = 1.037 CI (99.9%): [1287.463, 1289.802] (assumes normal distribution) ``` New (when follower fetch offset is updated): ``` 261.727 ±(99.9%) 0.122 ns/op [Average] (min, avg, max) = (261.565, 261.727, 261.937), stdev = 0.114 CI (99.9%): [261.605, 261.848] (assumes normal distribution) ``` New (when follower fetch offset is the same): ``` 68.484 ±(99.9%) 0.025 ns/op [Average] (min, avg, max) = (68.446, 68.484, 68.520), stdev = 0.023 CI (99.9%): [68.460, 68.509] (assumes normal distribution) ``` Reviewers: Ismael Juma <ismael@juma.me.uk>, Jason Gustafson <jason@confluent.io> 5 years ago			`<!DOCTYPE import-control PUBLIC`
			`"-//Puppy Crawl//DTD Import Control 1.1//EN"`
			`"http://www.puppycrawl.com/dtds/import_control_1_1.dtd">`
			`<!--`
			`// 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.`
			`-->`

			`<import-control pkg="org.apache.kafka.jmh">`

			`<allow pkg="java"/>`
			`<allow pkg="scala"/>`
			`<allow pkg="javax.management"/>`
			`<allow pkg="org.slf4j"/>`
			`<allow pkg="org.openjdk.jmh.annotations"/>`
			`<allow pkg="org.openjdk.jmh.runner"/>`
			`<allow pkg="org.openjdk.jmh.infra"/>`
			`<allow pkg="java.security"/>`
			`<allow pkg="javax.net.ssl"/>`
			`<allow pkg="javax.security"/>`
			`<allow pkg="org.apache.kafka.common"/>`
			`<allow pkg="org.apache.kafka.clients.producer"/>`
			`<allow pkg="kafka.cluster"/>`
			`<allow pkg="kafka.log"/>`
			`<allow pkg="kafka.server"/>`
			`<allow pkg="kafka.api"/>`
			`<allow class="kafka.utils.KafkaScheduler"/>`
			`<allow pkg="org.mockito"/>`


			`<subpackage name="cache">`
			`</subpackage>`
			`</import-control>`