kabutz / javaspecialists

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javaspecialists

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javaspecialists's Issues

Improve StripedExecutorService performance.

Hi,
I'm committer on Californium project, a CoAP java implementation.
In this project we also develop a DTLS layer named Scandium in which we use your StripedExecutorService.

Facing some CPU issue, I played with visualVM and see that scheduleNext() method is regularly mentioned in the hot-spot.
I don't think this is the real responsible of my CPU issue, but I was surprised to see this method seems to use more CPU than cryptographic stuff. I suspect the issue is the lock style implementation (mainly in SerialExecutor).

I read that you tried to enhance that, Did you succeed ?
We would like to improve this, do you have any advices or clues about the way to follow ?
Thx

Code and Config for Newsletter 285

Hello @kabutz, do you mind sharing code and config for below interesting test ?

https://www.javaspecialists.eu/archive/Issue285-I-O-Stream-Memory-Overhead.html

Jobs returned by shutdownNow

The shutdownNow returns a list with wrapper Runnables, created in the SerialExecutor.execute(). Executing these returned wrapper jobs results in potentially multiple removes of the related SerialExecutor, because the drainTo() empties the tasks queue and so every job execution tries to remove its SerialExecutor. That will fire the assert ser_ex == executors.get(stripe); in removeEmptySerialExecutor. Unwrapping these jobs will fix it.

Any/still interest in this improvement? The last change seems to be some time ago ...

You may have a look at my idea to fix it.
eclipse-californium/californium@b04bfeb

issue223 ManagedLivenessQueueDemo

run with jdk 17 throw following exception
Unable to make field private final java.util.concurrent.locks.ReentrantLock java.util.concurrent.LinkedBlockingQueue.takeLock accessible: module java.base does not "opens java.util.concurrent" to unnamed module @f6f4d33