Extension: Eager Thread Pool #1568

carryxyh · 2018-04-08T09:22:01Z

A thread pool that can provide faster processing speeds when there are more tasks (of course it consumes more resources)

When the number of tasks exceeds the core size, a new thread is first started to execute the task instead of putting it into the queue.
When the number of tasks is lower than the core size for a long time, the core size threads are maintained and redundant threads are recycled.
Compared to the fixed pool：When there are more tasks, provide more workers to handle the tasks.
Compared to the cached pool：The task queue in the cached pool is actually a SynchronousQueue and does not have the ability to cache tasks.
Whether to fail fail or put into a queue when a thread runs out：Both are feasible and need to consider which way should be applied according to the business scenario. Delayed scenarios are not allowed. Failfast is more reasonable than queues. However, if there is a certain tolerance for delays, queues are more reasonable than failfast.
Reference: Tomcat's thread pool design

A thread pool that can provide faster processing speeds when there are more tasks (of course it consumes more resources) * When the number of tasks exceeds the core size, a new thread is first started to execute the task instead of putting it into the queue. * When the number of tasks is lower than the core size for a long time, the core size threads are maintained and redundant threads are recycled. * Compared to the fixed pool：When there are more tasks, provide more workers to handle the tasks. * Compared to the cached pool：The task queue in the cached pool is actually a SynchronousQueue and does not have the ability to cache tasks. * Whether to fail fail or put into a queue when a thread runs out：Both are feasible and need to consider which way should be applied according to the business scenario. Delayed scenarios are not allowed. Failfast is more reasonable than queues. However, if there is a certain tolerance for delays, queues are more reasonable than failfast.

carryxyh · 2018-04-08T09:23:00Z

@beiwei30
clear the pull request and commit the changes with comment in English

zonghaishang · 2018-04-08T10:45:44Z

@carryxyh

Please add a license at the beginning of your codes to fix ci failed.

carryxyh · 2018-04-08T11:19:43Z

@zonghaishang thx!

codecov-io · 2018-04-08T14:10:09Z

Codecov Report

Merging #1568 into master will increase coverage by 0.08%.
The diff coverage is 57.14%.

@@            Coverage Diff             @@
##           master    #1568      +/-   ##
==========================================
+ Coverage   32.17%   32.25%   +0.08%     
==========================================
  Files         682      685       +3     
  Lines       32972    33019      +47     
  Branches     6597     6603       +6     
==========================================
+ Hits        10608    10650      +42     
+ Misses      20468    20464       -4     
- Partials     1896     1905       +9

Impacted Files	Coverage Δ
...eadpool/support/eager/EagerThreadPoolExecutor.java	`43.47% <43.47%> (ø)`
...bbo/common/threadpool/support/eager/TaskQueue.java	`56.25% <56.25%> (ø)`
...mmon/threadpool/support/eager/EagerThreadPool.java	`90% <90%> (ø)`
.../com/alibaba/dubbo/monitor/dubbo/DubboMonitor.java	`73.14% <0%> (-2.78%)`	⬇️
...bo/remoting/transport/netty/NettyCodecAdapter.java	`55.22% <0%> (-1.5%)`	⬇️
.../alibaba/dubbo/config/AbstractInterfaceConfig.java	`38% <0%> (-0.46%)`	⬇️
.../java/com/alibaba/dubbo/common/utils/NetUtils.java	`15.9% <0%> (+0.23%)`	⬆️
... and 3 more

Continue to review full report at Codecov.

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carryxyh · 2018-04-09T02:03:48Z

@beiwei30 @zonghaishang
CI failure has been resolved.

zonghaishang · 2018-04-09T02:22:49Z

Great !

beiwei30 · 2018-04-09T06:41:28Z

...on/src/main/java/com/alibaba/dubbo/common/threadpool/support/enhanced/EnhancedTaskQueue.java

+            throw new RejectedExecutionException("enhanced queue does not have executor !");
+        }
+        int currentPoolThreadSize = executor.getPoolSize();
+        //have free worker. put task into queue to let the worker deal with task.


leave space after //

beiwei30 · 2018-04-09T06:42:23Z

...on/src/main/java/com/alibaba/dubbo/common/threadpool/support/enhanced/EnhancedTaskQueue.java

+     */
+    public boolean retryOffer(Runnable o) {
+        if (executor.isShutdown()) {
+            throw new RejectedExecutionException("Executor is shutdown !");


change "Executor is shutdown !" to "Executor is shutdown!", there's one extra space.

beiwei30 · 2018-04-09T06:43:03Z

...on/src/main/java/com/alibaba/dubbo/common/threadpool/support/enhanced/EnhancedTaskQueue.java

+import java.util.concurrent.RejectedExecutionException;
+
+/**
+ * enhanced task queue in the enhanced thread pool


describe the behavior here

beiwei30 · 2018-04-09T06:43:55Z

...n/src/main/java/com/alibaba/dubbo/common/threadpool/support/enhanced/EnhancedThreadPool.java

+
+        //init queue and enhanced executor
+        EnhancedTaskQueue<Runnable> enhancedTaskQueue = new EnhancedTaskQueue<Runnable>(queues <= 0 ? 1 : queues);
+        EnhancedThreadPoolExecutor executor = new EnhancedThreadPoolExecutor(cores, threads, alive, TimeUnit.MILLISECONDS, enhancedTaskQueue,


keep line margin 120 chars.

beiwei30 · 2018-04-09T06:44:30Z

...n/src/main/java/com/alibaba/dubbo/common/threadpool/support/enhanced/EnhancedThreadPool.java

+
+/**
+ * enhanced thread pool.
+ * When the core threads are all in busy , create new thread instead of putting task into blocking queue .


remove extra space from 'blocking queue .'

beiwei30 · 2018-04-09T06:45:17Z

...in/java/com/alibaba/dubbo/common/threadpool/support/enhanced/EnhancedThreadPoolExecutor.java

+    //task count
+    private final AtomicInteger submittedTaskCount = new AtomicInteger(0);
+
+    public EnhancedThreadPoolExecutor(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit, EnhancedTaskQueue<Runnable> workQueue, ThreadFactory threadFactory, RejectedExecutionHandler handler) {


keep line margin 120 chars.

beiwei30 · 2018-04-09T06:45:39Z

...in/java/com/alibaba/dubbo/common/threadpool/support/enhanced/EnhancedThreadPoolExecutor.java

+
+    @Override
+    public void execute(Runnable command) {
+        //do not increment in method beforeExecute!


add space after //

beiwei30 · 2018-04-09T06:45:51Z

...in/java/com/alibaba/dubbo/common/threadpool/support/enhanced/EnhancedThreadPoolExecutor.java

+        try {
+            super.execute(command);
+        } catch (RejectedExecutionException rx) {
+            //retry to offer the task into queue .


add space after //

beiwei30 · 2018-04-09T06:46:51Z

...in/java/com/alibaba/dubbo/common/threadpool/support/enhanced/EnhancedThreadPoolExecutor.java

+        submittedTaskCount.incrementAndGet();
+        try {
+            super.execute(command);
+        } catch (RejectedExecutionException rx) {


what happens if exception other than RejectedExecutionException is thrown? then submittedTaskCount may have no change to decrease.

It can not be a problem because the submittedTaskCount will be decreased in the 'afterExecute' method.
But the RejectedExecutionException is thrown before the task run. So when the RejectedExecutionException is thrown , we should decrease the submittedTaskCount.

beiwei30 · 2018-04-09T06:49:12Z

...on/src/main/java/com/alibaba/dubbo/common/threadpool/support/enhanced/EnhancedTaskQueue.java

+ * limitations under the License.
+ */
+
+package com.alibaba.dubbo.common.threadpool.support.enhanced;


I suggest change 'enhanced' into other word, more accurate to describe the behavior, for example: eager or greedy? once decided, pls. change package name, class name, and comments.

How about EagerThreadPoolExecutor means the executor is eager to more tasks.

modify sth with the code review format the code file

* Extension: Enhanced Thread Pool A thread pool that can provide faster processing speeds when there are more tasks (of course it consumes more resources) * When the number of tasks exceeds the core size, a new thread is first started to execute the task instead of putting it into the queue. * When the number of tasks is lower than the core size for a long time, the core size threads are maintained and redundant threads are recycled. * Compared to the fixed pool：When there are more tasks, provide more workers to handle the tasks. * Compared to the cached pool：The task queue in the cached pool is actually a SynchronousQueue and does not have the ability to cache tasks. * Whether to fail fail or put into a queue when a thread runs out：Both are feasible and need to consider which way should be applied according to the business scenario. Delayed scenarios are not allowed. Failfast is more reasonable than queues. However, if there is a certain tolerance for delays, queues are more reasonable than failfast. * remove * in import * add license to fix ci failure * rename the thread pool to EagerThreadPool modify sth with the code review format the code file * remove '*' in import statement * throw NullPointerException if the param is null. * throw NullPointerException if the param is null. * catch throwable and decrease submitted task count anyway

remove * in import

8bbe58f

add license to fix ci failure

8f10d9e

beiwei30 requested changes Apr 9, 2018

View reviewed changes

carryxyh added 2 commits April 9, 2018 16:13

rename the thread pool to EagerThreadPool

443d4e6

modify sth with the code review format the code file

remove '*' in import statement

eb2c406

carryxyh changed the title ~~Extension: Enhanced Thread Pool~~ Extension: Eager Thread Pool Apr 9, 2018

carryxyh added 4 commits April 9, 2018 17:56

throw NullPointerException if the param is null.

07f3de0

Merge remote-tracking branch 'upstream/master' into enhanced

9f4f379

throw NullPointerException if the param is null.

6bee8ea

catch throwable and decrease submitted task count anyway

ec25e88

beiwei30 approved these changes Apr 9, 2018

View reviewed changes

beiwei30 merged commit 38f45ee into apache:master Apr 9, 2018

chickenlj added this to the 2.6.2 milestone Apr 24, 2018

EruDev mentioned this pull request Nov 15, 2020

八股文 EruDev/Java365#9

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Extension: Eager Thread Pool #1568

Extension: Eager Thread Pool #1568

carryxyh commented Apr 8, 2018

carryxyh commented Apr 8, 2018

zonghaishang commented Apr 8, 2018

carryxyh commented Apr 8, 2018

codecov-io commented Apr 8, 2018 •

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carryxyh commented Apr 9, 2018

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carryxyh Apr 9, 2018

Extension: Eager Thread Pool #1568

Extension: Eager Thread Pool #1568

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carryxyh commented Apr 8, 2018

carryxyh commented Apr 8, 2018

zonghaishang commented Apr 8, 2018

carryxyh commented Apr 8, 2018

codecov-io commented Apr 8, 2018 • edited Loading

Codecov Report

carryxyh commented Apr 9, 2018

zonghaishang commented Apr 9, 2018

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codecov-io commented Apr 8, 2018 •

edited

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