3a96e7373b
Motivation: Add an option (through a SelectStrategy return code) to have the Netty event loop thread to do busy-wait on the epoll. The reason for this change is to avoid the context switch cost that comes when the event loop thread is blocked on the epoll_wait() call. On average, the context switch has a penalty of ~13usec. This benefits both: The latency when reading from a socket Scheduling tasks to be executed on the event loop thread. The tradeoff, when enabling this feature, is that the event loop thread will be using 100% cpu, even when inactive. Modification: Added SelectStrategy option to return BUSY_WAIT Epoll loop will do a epoll_wait() with no timeout Use pause instruction to hint to processor that we're in a busy loop Result: When enabled, minimizes impact of context switch in the critical path
32 lines
1.3 KiB
Java
32 lines
1.3 KiB
Java
/*
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* Copyright 2018 The Netty Project
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*
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* The Netty Project licenses this file to you under the Apache License,
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* version 2.0 (the "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*/
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package io.netty.channel.epoll;
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import io.netty.bootstrap.Bootstrap;
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import io.netty.bootstrap.ServerBootstrap;
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import io.netty.buffer.ByteBufAllocator;
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public class EpollETSocketStringEchoBusyWaitTest extends EpollSocketStringEchoBusyWaitTest {
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@Override
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protected void configure(ServerBootstrap bootstrap, Bootstrap bootstrap2, ByteBufAllocator allocator) {
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super.configure(bootstrap, bootstrap2, allocator);
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bootstrap.option(EpollChannelOption.EPOLL_MODE, EpollMode.EDGE_TRIGGERED)
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.childOption(EpollChannelOption.EPOLL_MODE, EpollMode.EDGE_TRIGGERED);
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bootstrap2.option(EpollChannelOption.EPOLL_MODE, EpollMode.EDGE_TRIGGERED);
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}
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}
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