threadpool | Parallel Processing in R using a Thread Pool | Architecture library

 by   rdpeng R Version: Current License: No License

kandi X-RAY | threadpool Summary

kandi X-RAY | threadpool Summary

threadpool is a R library typically used in Architecture applications. threadpool has no bugs, it has no vulnerabilities and it has low support. You can download it from GitHub.

Parallel Processing in R using a Thread Pool
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              threadpool has a low active ecosystem.
              It has 60 star(s) with 17 fork(s). There are 9 watchers for this library.
              OutlinedDot
              It had no major release in the last 6 months.
              There are 2 open issues and 1 have been closed. There are no pull requests.
              It has a neutral sentiment in the developer community.
              The latest version of threadpool is current.

            kandi-Quality Quality

              threadpool has 0 bugs and 0 code smells.

            kandi-Security Security

              threadpool has no vulnerabilities reported, and its dependent libraries have no vulnerabilities reported.
              threadpool code analysis shows 0 unresolved vulnerabilities.
              There are 0 security hotspots that need review.

            kandi-License License

              threadpool does not have a standard license declared.
              Check the repository for any license declaration and review the terms closely.
              OutlinedDot
              Without a license, all rights are reserved, and you cannot use the library in your applications.

            kandi-Reuse Reuse

              threadpool releases are not available. You will need to build from source code and install.
              Installation instructions are not available. Examples and code snippets are available.
              It has 2628 lines of code, 0 functions and 26 files.
              It has low code complexity. Code complexity directly impacts maintainability of the code.

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            threadpool Key Features

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            threadpool Examples and Code Snippets

            No Code Snippets are available at this moment for threadpool.

            Community Discussions

            QUESTION

            Python multiprocessing - number of threadpools not multiplied by number of pools
            Asked 2022-Mar-20 at 17:22

            I have a python 3.9 code that uses Pool and ThreadPool from multiprocessing.pool. The intention is to have 2 Pools, each spawning 3 ThreadPools independently. In other words, I expect 2*3 = 6 threads running in parallel.

            However, the output of the minimum working example (MWE) code below resulted in only 3 different thread ids.

            My question: Why does it behave like this, and how can I reasonably fix that?

            In addition, if such a N_POOL * N_THREADPOOL strategy does not look good, advice is welcomed. The actual task is I/O-bound (network download followed by light preprocessing). I am relatively new to parallelism.

            MWE Code ...

            ANSWER

            Answered 2022-Mar-20 at 16:15

            You didn't specify what platform you are running under but I must assume it is one that uses fork to create new processes (such as Linux) or I don't believe your code would work correctly because under spawn each process in the pool would be creating its own copy of global CPU_QUEUE and thus would each be getting the first item on the queue and believe that it is CPU id 1.

            I have consequently made two changes to the code:

            1. Made the code more portable between platforms by using a pool initializer to initialize global variable CPU_QUEUE for each process in the pool with a single queue instance.
            2. Introduced a call to time.sleep at the start of function process_pool to give each process in the pool a chance to process one of the submitted tasks. Without this it could theoretically be possible for one process in the pool to process all the submitted tasks and this just make that less likely.

            When I run the code under Linux I essentially see what you see. However, when I run this under Windows, which I am now able to do because of the above changes, I see:

            Source https://stackoverflow.com/questions/71540533

            QUESTION

            Max Number of threads in java executorService with tomcat
            Asked 2022-Mar-10 at 05:05

            Tomcat allows by default max 200 threads to process requests in a Spring Boot application. Lets say within the application, during the start of the process, I create a FixedThreadpool of size say 10.

            Now when I am trying to use this thing with tomcat, what would be the max total number of threads that I will be running. Will it be 200 + 10 or 200 * 10?

            My understanding is that it will be 200 + 10 as at the process level only java will create the threadpool and use that threadpool whereever required.

            Also will it depend on how i initiate the threadpool? For example let's say I create a bean of threadpool executor and use that across the system.

            ...

            ANSWER

            Answered 2022-Mar-10 at 05:05

            For one application instance running on tomcat, tomcat will have one threadpool created when the server starts, the application will have the fixed threadpool created on startup. This is not a shared nothing cgi, it's a single long running java process that stays in memory, 200 + 10 is right.

            If you create a pool within a method call then each method call would allocate its own pool. So if every thread in tomcats pool was concurrently making a request that called a method that created its own pool then the number of threads in use could be up to the tomcat pool size times the method pool size.

            Generally I would recommend not doing this because it would seem to undercut two advantages of using a pool: 1) that you can preallocate threads so your code doesn't have to wait on thread creation, and 2) that you can put an upper bound on the maximum number of threads your program uses.

            Source https://stackoverflow.com/questions/71418676

            QUESTION

            java.lang.Exception: Host is not set (running a JakartaEE app on Payara micro, behind nginx)
            Asked 2022-Jan-15 at 18:05

            This error trace is polluting my logs and I can't find on SA or else what is causing it:

            ...

            ANSWER

            Answered 2022-Jan-15 at 18:05

            Looks like Grizzly is trying to obtain the hostname from the Host header in the request. Since HTTP 1.1 the Host header is required but if the Host header is set an empty name, Grizzly cannot obtain the name and throws an exception.

            The Host request header is set by the HTTP client. But even if the Host header exists but its value is empty due to some reason the exception will be thrown.

            Grizzly Code: the code that throws the Exception

            According to the Javadocs for Grizzly you can set the default hostname by calling the setDefaultHostName(String defaultHostName) method, but the instance of the Mapper in the HttpHanderChain instance is not exposed. The default value set in HttpHanderChain of the Mapper instance is set to "localhost".

            Source https://stackoverflow.com/questions/70679599

            QUESTION

            Why does okhttp3 connection pool use Int.MAX_VALUE as maximumPoolSize?
            Asked 2021-Dec-27 at 21:35

            When a large number of requests are executed, a large number of threads are created to maintain idle connections, and these threads are in the TIMED_WAITING state for five minutes.

            The following source code exists in the latest version:

            ...

            ANSWER

            Answered 2021-Dec-27 at 21:04

            OkHttp limits its own resource usage limits, but not here. Instead, Dispatcher limits how many calls are in flight concurrently, and ConnectionPool limits how many connections are alive.

            Source https://stackoverflow.com/questions/70496944

            QUESTION

            reading large file uses 100% memory and my whole pc frozes
            Asked 2021-Dec-20 at 12:42

            I have made a simple app that encrypts and decrypts files. but when i load a large file like a 2gb, my program uses 100% of the memory. I use multiprocessing and multi threading.

            ...

            ANSWER

            Answered 2021-Dec-20 at 12:42

            This is my general idea:

            Since memory is a problem, you have to read the files in smaller chunks, say 64K pieces and encrypt each 64K block and write those out. Of course, the encrypted block will have a length other than 64K so the problem becomes how to decrypt. So each encrypted block must be prefixed with a fixed-length header that is nothing more than the length of the following encrypted block encoded as a 4-byte unsigned integer (which should be way more than adequate). The decryption algorithm loop first reads the next 4-byte length and then know from that how many bytes long is the encrypted block that follows.

            By the way, there is no need to pass to encfile a lock if you are not using it to, for example, count files processed.

            Source https://stackoverflow.com/questions/70378894

            QUESTION

            How do I resolve list index out of range error?
            Asked 2021-Dec-18 at 07:42

            I have a code that scrapes data into a dataframe

            ...

            ANSWER

            Answered 2021-Dec-18 at 07:42

            The fact that you get an IndexError when accessing td_tags implies that len(td_tags) is not always 6 or 7. It is <6 at least once.

            Look at this bit of code:

            Source https://stackoverflow.com/questions/70401284

            QUESTION

            SpinLock doesn't really do busy-loop waiting?
            Asked 2021-Dec-10 at 00:25

            I have the following code

            ...

            ANSWER

            Answered 2021-Dec-10 at 00:25

            Regarding your edited question, yes busy spinning will give you the lowest latency of communication between the threads but you will pay for it by burning CPU time.

            On the other hand you can use SpinWait which is less aggressive or you can code something in between such as this.

            It comes down to a trade-off on how much you value latency and how many cores you have to spare.

            Source https://stackoverflow.com/questions/70294914

            QUESTION

            GitHub action fails on npm ci
            Asked 2021-Dec-04 at 00:35

            I have git action to run prettier(Code formatter). Below is the format.yml file of git action.

            ...

            ANSWER

            Answered 2021-Dec-03 at 17:09

            It seems you are running different node version in your githubAction.

            Set up the same node version that you use local(e.g. 14) before to run npm ci:

            Source https://stackoverflow.com/questions/70217629

            QUESTION

            How does Task.Yield work under the hood in Blazor WebAssembly?
            Asked 2021-Nov-28 at 11:17

            How does Task.Yield work under the hood in Mono/WASM runtime (which is used by Blazor WebAssembly)?

            To clarify, I believe I have a good understanding of how Task.Yield works in .NET Framework and .NET Core. Mono implementation doesn't look much different, in a nutshell, it comes down to this:

            ...

            ANSWER

            Answered 2021-Nov-28 at 11:17

            It’s setTimeout. There is considerable indirection between that and QueueUserWorkItem, but this is where it bottoms out.

            Most of the WebAssembly-specific machinery can be seen in PR 38029. The WebAssembly implementation of RequestWorkerThread calls a private method named QueueCallback, which is implemented in C code as mono_wasm_queue_tp_cb. This in invokes mono_threads_schedule_background_job, which in turn calls schedule_background_exec, which is implemented in TypeScript as:

            Source https://stackoverflow.com/questions/70091469

            QUESTION

            Async/await: who is waiting/blocking?
            Asked 2021-Nov-27 at 07:20

            I'm trying to understand async/await and read the source code of AsyncMethodBuilder. I thought there must be some code like xxx.Wait() or xxx.WaitOnce() waiting for a task to be completed.

            However, I didn't find such code in class AsyncMethodBuilder.

            system\runtime\compilerservices\AsyncMethodBuilder.cs https://referencesource.microsoft.com/#mscorlib/system/runtime/compilerservices/AsyncMethodBuilder.cs,96

            So I keep digging, tried to read the source code of Task, TaskScheduler, ThreadPoolTaskScheduler, ThreadPool.

            Finally I got class _ThreadPoolWaitCallback, but didn't find any caller. https://referencesource.microsoft.com/#mscorlib/system/threading/threadpool.cs,d7b8a78b4dd14fd0

            ...

            ANSWER

            Answered 2021-Nov-27 at 07:20

            In a correctly implemented async implementation: there is no wait. Instead, at the bottom of the chain, some code exists that will create some async source, which could be a TaskCompletionSource, an IValueTaskSource[], or something similar - which allows that code to store that token somewhere (for example, in a queue, a correlation dictionary, or an async state object for IOCP), and return the incomplete task to the caller. The caller then discovers that it is incomplete, and registers a "when you have the answer, do this to reactivate me" callback. That calling code now unwinds completely, with every step saying "when you're done, push here", and the thread goes on to do other things, such as service a different request.

            At some point in the future (hopefully), the result will come back - again, via IOCP, or via a separate IO reader pulling a response from somewhere and taking the appropriate item out of the queue/correlation-dictionary, and says "the outcome was {...}" (TrySetResult, TrySetException, etc).

            For all of that time no threads were blocked. That is, ultimately, the entire point of async/await: to free up threads, to increase scalability.

            In incorrectly implemented async systems: anything and everything is possible, including async-over-sync, sync-over-async, and everything else.

            Source https://stackoverflow.com/questions/70131799

            Community Discussions, Code Snippets contain sources that include Stack Exchange Network

            Vulnerabilities

            No vulnerabilities reported

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            You can download it from GitHub.

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