the execution of multiple concurrent processes in a system
Questions tagged [multiple-processes]
110 questions
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PHP and C: to avoid to execute multiples processes of the same C program
I am developing a PHP web interface to manage the GPIO of my Raspberry.
I would like to create a page with for example four buttons:
Button 1: switch ON PIN1
Button 2: switch OFF PIN1
Button 3: switch ON PIN2
Button 4: switch OFF PIN2
To each…
Eric_Predict
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Why is wait-time important criteria for CPU scheduling algorithms?
For example when I read about different scheduling algorithms like First-Come-First-Serve, Shortest Job First, Priority Scheduling, Round Robin scheduling for all of them the measure is average wait time.
Consider a processes with run times of 21,…
CupOfCoffee
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python multiprocessing script does not exit
I am trying to get a little bit more comfortabl with the python2.7 multiprocessing module. So I have written a small script that takes filenames and the desired number of processes as input, and then starts multiple processes to apply a function to…
sequence_hard
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Python SQLite3 using multiple processes for concurrent reading: often hangs without raising error on big dataset
Overview:
I am trying to create a large number of variables (wide dataset) for a financial data analysis project. I have a pandas dataframe "position_history" with 140,000 rows, each containing a stock and buy and sell dates/prices.
I have a…
waywocket
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Why is my node child_process terminating early?
I am trying to run an async node child_process which runs a docker container.
let runDockerCmd = `docker-compose -f ./vm/docker-compose.yml run --rm vm node temp.js`;
child_process.exec(runDockerCmd, (error, stdout, stderr) => {
if (error) {
…
Dylan Harness
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Start n sub-processes in bash and wait till everything is finished
I'd like to test out several ffmpeg settings and run multiple commands as 'sub-processes'. I would not like to launch more than 4 processes at a time, though. What is a good way to do this? Maybe something like trapping the process id's before…
HotDogCannon
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Is it possible that some processes in this program finish sooner than others?
I have a program which is designed to be highly parallelizable. I suspect that some processors are finishing this Python script sooner then other processors, which would explain behavior I observe upstream of this code. Is it possible that this code…
kilojoules
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Understanding unix child processes that use semaphore and shared memory
I'm going to do my best to ask this question with the understanding that I have.
I'm doing a programming assignment (let's just get that out of the way now) that uses C or C++ on a Unix server to fork four children and use semaphore and shared…
LumberSzquatch
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VHDL Multiple Processes error
I am writing a VHDL homework, which produces a strange behavior, which I do not understand.
The concept is the following. There should be an LFSR which is used to generate random numbers. The LFSR could be driven by I_CLK or by I_NEXT input. If the…
ToMmY_hun
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Redraw issues in GTK+
I have a call to an external program that opens a "modal" window, since it's in the same thread as the main loop it blocks redrawing of the underlying window.
The program runs as a separate process and I am communicating with the program via…
Didi Kohen
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1 answer
Parent process does not reap child return variable
This is for a class so I am trying to understand why the variable nChars is not being set when the child process returns. I have read that waitpid() reaps the child process but when I try to print nChars it still shows zero when the childs' nChars…
thepi
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In Android, how to prevent multiple process writing to the same file
In my app, i will check to see if unique id generated before, if not, it will generate one and write it to a file. But in a multiple processes app, it feels has problem when multiple process try to writing to this same file if they both find there's…
xiaoweiz
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timing control for parallel processes
how can i control two processes to run alternately in separate terminal windows.
for example i run the code for each on separate terminal windows at 11:59 and both of them wait for the time to be 12:00. at this moment process one starts execution…
omrihsan
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Reader and writer process SQLite
I have two processes:
Writes to two tables every second (ish)
Reads from said tables periodically
I know that with SQLite, any writes lock the whole database and so sometimes the second process can fail with a locked database.
Is there anything…
Sohail
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Locking a file for race conditons perl
I am working on a script for no good reason spawns two extra processes when it run. To combat this i wrote i file lock routine. But because these extra processes are running at the same time this does not seem to work at all. what am i missing here.…
Opad
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