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Refactor RateLimiterController: improve accuracy and support maxQps >…
… 1000 * Rename to ThrottlingController * Improve accuracy: use nanoseconds when necessary and support maxQps threshold > 1000 (i.e. wait < 1ms) Signed-off-by: Eric Zhao <[email protected]>
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93 changes: 0 additions & 93 deletions
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...main/java/com/alibaba/csp/sentinel/slots/block/flow/controller/RateLimiterController.java
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.../main/java/com/alibaba/csp/sentinel/slots/block/flow/controller/ThrottlingController.java
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,167 @@ | ||
| /* | ||
| * Copyright 1999-2022 Alibaba Group Holding Ltd. | ||
| * | ||
| * 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 | ||
| * | ||
| * https://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 com.alibaba.csp.sentinel.slots.block.flow.controller; | ||
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| import java.util.concurrent.TimeUnit; | ||
| import java.util.concurrent.atomic.AtomicLong; | ||
| import java.util.concurrent.locks.LockSupport; | ||
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| import com.alibaba.csp.sentinel.node.Node; | ||
| import com.alibaba.csp.sentinel.slots.block.flow.TrafficShapingController; | ||
| import com.alibaba.csp.sentinel.util.AssertUtil; | ||
| import com.alibaba.csp.sentinel.util.TimeUtil; | ||
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| /** | ||
| * @author Eric Zhao | ||
| * @author jialiang.linjl | ||
| * @since 2.0 | ||
| */ | ||
| public class ThrottlingController implements TrafficShapingController { | ||
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| // Refactored from legacy RateLimitController of Sentinel 1.x. | ||
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| private static final long MS_TO_NS_OFFSET = TimeUnit.MILLISECONDS.toNanos(1); | ||
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| private final int maxQueueingTimeMs; | ||
| private final int statDurationMs; | ||
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| private final double count; | ||
| private final boolean useNanoSeconds; | ||
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| private final AtomicLong latestPassedTime = new AtomicLong(-1); | ||
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| public ThrottlingController(int queueingTimeoutMs, double maxCountPerStat) { | ||
| this(queueingTimeoutMs, maxCountPerStat, 1000); | ||
| } | ||
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| public ThrottlingController(int queueingTimeoutMs, double maxCountPerStat, int statDurationMs) { | ||
| AssertUtil.assertTrue(statDurationMs > 0, "statDurationMs should be positive"); | ||
| AssertUtil.assertTrue(maxCountPerStat >= 0, "maxCountPerStat should be >= 0"); | ||
| AssertUtil.assertTrue(queueingTimeoutMs >= 0, "queueingTimeoutMs should be >= 0"); | ||
| this.maxQueueingTimeMs = queueingTimeoutMs; | ||
| this.count = maxCountPerStat; | ||
| this.statDurationMs = statDurationMs; | ||
| // Use nanoSeconds when durationMs%count != 0 or count/durationMs> 1 (to be accurate) | ||
| if (maxCountPerStat > 0) { | ||
| this.useNanoSeconds = statDurationMs % Math.round(maxCountPerStat) != 0 || maxCountPerStat / statDurationMs > 1; | ||
| } else { | ||
| this.useNanoSeconds = false; | ||
| } | ||
| } | ||
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| @Override | ||
| public boolean canPass(Node node, int acquireCount) { | ||
| return canPass(node, acquireCount, false); | ||
| } | ||
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| private boolean checkPassUsingNanoSeconds(int acquireCount, double maxCountPerStat) { | ||
| final long maxQueueingTimeNs = maxQueueingTimeMs * MS_TO_NS_OFFSET; | ||
| long currentTime = System.nanoTime(); | ||
| // Calculate the interval between every two requests. | ||
| final long costTimeNs = Math.round(1.0d * MS_TO_NS_OFFSET * statDurationMs * acquireCount / maxCountPerStat); | ||
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| // Expected pass time of this request. | ||
| long expectedTime = costTimeNs + latestPassedTime.get(); | ||
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| if (expectedTime <= currentTime) { | ||
| // Contention may exist here, but it's okay. | ||
| latestPassedTime.set(currentTime); | ||
| return true; | ||
| } else { | ||
| final long curNanos = System.nanoTime(); | ||
| // Calculate the time to wait. | ||
| long waitTime = costTimeNs + latestPassedTime.get() - curNanos; | ||
| if (waitTime > maxQueueingTimeNs) { | ||
| return false; | ||
| } | ||
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| long oldTime = latestPassedTime.addAndGet(costTimeNs); | ||
| waitTime = oldTime - curNanos; | ||
| if (waitTime > maxQueueingTimeNs) { | ||
| latestPassedTime.addAndGet(-costTimeNs); | ||
| return false; | ||
| } | ||
| // in race condition waitTime may <= 0 | ||
| if (waitTime > 0) { | ||
| sleepNanos(waitTime); | ||
| } | ||
| return true; | ||
| } | ||
| } | ||
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| private boolean checkPassUsingCachedMs(int acquireCount, double maxCountPerStat) { | ||
| long currentTime = TimeUtil.currentTimeMillis(); | ||
| // Calculate the interval between every two requests. | ||
| long costTime = Math.round(1.0d * statDurationMs * acquireCount / maxCountPerStat); | ||
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| // Expected pass time of this request. | ||
| long expectedTime = costTime + latestPassedTime.get(); | ||
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| if (expectedTime <= currentTime) { | ||
| // Contention may exist here, but it's okay. | ||
| latestPassedTime.set(currentTime); | ||
| return true; | ||
| } else { | ||
| // Calculate the time to wait. | ||
| long waitTime = costTime + latestPassedTime.get() - TimeUtil.currentTimeMillis(); | ||
| if (waitTime > maxQueueingTimeMs) { | ||
| return false; | ||
| } | ||
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| long oldTime = latestPassedTime.addAndGet(costTime); | ||
| waitTime = oldTime - TimeUtil.currentTimeMillis(); | ||
| if (waitTime > maxQueueingTimeMs) { | ||
| latestPassedTime.addAndGet(-costTime); | ||
| return false; | ||
| } | ||
| // in race condition waitTime may <= 0 | ||
| if (waitTime > 0) { | ||
| sleepMs(waitTime); | ||
| } | ||
| return true; | ||
| } | ||
| } | ||
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| @Override | ||
| public boolean canPass(Node node, int acquireCount, boolean prioritized) { | ||
| // Pass when acquire count is less or equal than 0. | ||
| if (acquireCount <= 0) { | ||
| return true; | ||
| } | ||
| // Reject when count is less or equal than 0. | ||
| // Otherwise, the costTime will be max of long and waitTime will overflow in some cases. | ||
| if (count <= 0) { | ||
| return false; | ||
| } | ||
| if (useNanoSeconds) { | ||
| return checkPassUsingNanoSeconds(acquireCount, this.count); | ||
| } else { | ||
| return checkPassUsingCachedMs(acquireCount, this.count); | ||
| } | ||
| } | ||
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| private void sleepMs(long ms) { | ||
| try { | ||
| Thread.sleep(ms); | ||
| } catch (InterruptedException e) { | ||
| } | ||
| } | ||
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| private void sleepNanos(long ns) { | ||
| LockSupport.parkNanos(ns); | ||
| } | ||
|
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| } |
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