multiprocess

Deadlock with logging multiprocess/multithread python script

放肆的年华 提交于 2019-11-29 07:34:23
I am facing the problem with collecting logs from the following script. Once I set up the SLEEP_TIME to too "small" value, the LoggingThread threads somehow block the logging module. The script freeze on logging request in the action function. If the SLEEP_TIME is about 0.1 the script collect all log messages as I expect. I tried to follow this answer but it does not solve my problem. import multiprocessing import threading import logging import time SLEEP_TIME = 0.000001 logger = logging.getLogger() ch = logging.StreamHandler() ch.setFormatter(logging.Formatter('%(asctime)s %(levelname)s %

Multiprocess multiple files in a list

限于喜欢 提交于 2019-11-29 05:12:22
I am trying to read a list that contains N number of .csv files stored in a list synchronously. Right now I do the following: import multiprocess Empty list Append list with listdir of .csv's def A() -- even files (list[::2]) def B() -- odd files (list[1::2] Process 1 def A() Process 2 def B() def read_all_lead_files(folder): for files in glob.glob(folder+"*.csv"): file_list.append(files) def read_even(): file_list[::2] def read_odd(): file_list[1::2] p1 = Process(target=read_even) p1.start() p2 = Process(target=read_odd) p2.start() Is there a faster way to split up the partitioning of the

Python multicore programming [duplicate]

烈酒焚心 提交于 2019-11-28 23:40:10
This question already has an answer here: Threading in Python [closed] 7 answers Please consider a class as follow: class Foo: def __init__(self, data): self.data = data def do_task(self): #do something with data In my application I've a list containing several instances of Foo class. The aim is to execute do_task for all Foo objects. A first implementation is simply: #execute tasks of all Foo Object instantiated for f_obj in my_foo_obj_list: f_obj.do_task() I'd like to take advantage of multi-core architecture sharing the for cycle between 4 CPUs of my machine. What's the best way to do it?

Mutex lock threads

会有一股神秘感。 提交于 2019-11-28 18:15:29
Am new to multi threaded/processs programming. So here's what I need to clarify. Process A code pthread_mutex_lock() pthread_create(fooAPI(sharedResource)) //fooAPI creates another thread with shared resource that shares across processes. pthread_mutex_unlock() With the above pseudo code, is process B able to access sharedResource if mutex is not unlocked? How can I access the sharedResource from process B correctly? Any there any clear visual diagram that explains the relationship between mutexes, threads and processes? What you need to do is to call pthread_mutex_lock to secure a mutex, like

How can Google Chrome isolate tabs into separate processes while looking like a single application?

馋奶兔 提交于 2019-11-28 16:21:28
We have been told that Google Chrome runs each tab in a separate process. Therefore a crash in one tab would not cause problems in the other tabs. AFAIK, multi-processes are mostly used in programs without a GUI. I have never read any technique that could embed multiple GUI processes into a single one. How does Chrome do that? I am asking this question because I am designing CCTV software which will use video decoding SDKs from multiple camera manufactures, some of which are far from stable. So I prefer to run these SDKs in different processes, which I thought is similar to Chrome. Basically,

Python Multiprocessing help exit on condition

允我心安 提交于 2019-11-28 05:42:29
问题 I'm breaking my teeth on multiprocessing within Python but I'm not having any luck wrapping my head around the subject. Basically I have a procedure that is time consuming to run. I need to run it for a range of 1 to 100 but I'd like to abort all processes once the condition I'm looking for has been met. The condition being the return value == 90. Here is a non multiprocess chunk of code. Can anyone give me an example of how they would convert it to a multiprocess function where the the code

Deadlock with logging multiprocess/multithread python script

和自甴很熟 提交于 2019-11-28 01:16:31
问题 I am facing the problem with collecting logs from the following script. Once I set up the SLEEP_TIME to too "small" value, the LoggingThread threads somehow block the logging module. The script freeze on logging request in the action function. If the SLEEP_TIME is about 0.1 the script collect all log messages as I expect. I tried to follow this answer but it does not solve my problem. import multiprocessing import threading import logging import time SLEEP_TIME = 0.000001 logger = logging

Multiprocess multiple files in a list

亡梦爱人 提交于 2019-11-27 21:56:39
问题 I am trying to read a list that contains N number of .csv files stored in a list synchronously. Right now I do the following: import multiprocess Empty list Append list with listdir of .csv's def A() -- even files (list[::2]) def B() -- odd files (list[1::2] Process 1 def A() Process 2 def B() def read_all_lead_files(folder): for files in glob.glob(folder+"*.csv"): file_list.append(files) def read_even(): file_list[::2] def read_odd(): file_list[1::2] p1 = Process(target=read_even) p1.start()

multiprocess or threading in python?

泄露秘密 提交于 2019-11-27 06:53:52
I have a python application that grabs a collection of data and for each piece of data in that collection it performs a task. The task takes some time to complete as there is a delay involved. Because of this delay, I don't want each piece of data to perform the task subsequently, I want them to all happen in parallel. Should I be using multiprocess? or threading for this operation? I attempted to use threading but had some trouble, often some of the tasks would never actually fire. If you are truly compute bound, using the multiprocessing module is probably the lightest weight solution (in

how to write a process-pool bash shell

泪湿孤枕 提交于 2019-11-27 04:17:33
问题 I have more than 10 tasks to execute, and the system restrict that there at most 4 tasks can run at the same time. My task can be started like: myprog taskname How can I write a bash shell script to run these task. The most important thing is that when one task finish, the script can start another immediately, making the running tasks count remain 4 all the time. 回答1: I chanced upon this thread while looking into writing my own process pool and particularly liked Brandon Horsley's solution,