multiprocess

问题 I want to run a thread for sending email periodically. In the same program, I am creating processes to do another task. When I create the task, thread from original process is copied to these sub processes and I end up receiving multiple emails instead of one. How can I make sure that thread I run in main program is not copied to the sub processes that are created? 来源： https://stackoverflow.com/questions/19320756/prevent-multiple-instances-of-threads-for-multiprocessing-python

问题 Is there a difference in performance or other between creating a multi-process program using the linux "fork" and the functions available in the MPI library? Or is it just easier to do it in MPI because of the ready to use functions? 回答1: They don't solve the same problem. Note the difference between parallel programming and distributed-memory parallel programming. Using the fork/join model you mentioned usually is for parallel programming on the same physical machine. You generally don't

问题 I developed a program in C++ for research purpose. It takes several days to complete. Now i executing it on our lab 8core server machine to get results quickly, but i see machine assigns only one processor to my program and it remains at 13% processor usage(even i set process priority at high level and affinity for 8 cores). (It is a simple object oriented program without any parallelism or multi threading) How i can get true benefit from the powerful server machine? Thanks in advance. 回答1:

问题 This question already has answers here : Threading in Python [closed] (7 answers) Closed 5 years ago . 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

问题 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

问题 I am having issues with my halt_listener thread. I can start import_1 but it will not spawn a halt_listener thread. I am patterning this after known good code, the only difference was in the last iteration the halt_listener got fed a pipe instead of a queue. class test_imports:#Test classes remove alive = {'import_1': True, 'import_2': True}; def halt_listener(self, control_Queue, thread_Name, kill_command): while True: print ("Checking queue for kill") isAlive = control_queue.get() print (

问题 Yesterday i asked a question: Reading data in parallel with multiprocess I got very good answers, and i implemented the solution mentioned in the answer i marked as correct. def read_energies(motif): os.chdir("blabla/working_directory") complx_ener = pd.DataFrame() # complex function to fill that dataframe lig_ener = pd.DataFrame() # complex function to fill that dataframe return motif, complx_ener, lig_ener COMPLEX_ENERGIS = {} LIGAND_ENERGIES = {} p = multiprocessing.Pool(processes=CPU) for

问题 I was about to write a shell with C language. Here is the source code below: #include <unistd.h> #include <stdio.h> #include <string.h> #include <sys/wait.h> #include <stdlib.h> int getcmd(char *buf, int nbuf) { memset(buf, 0, nbuf); fgets(buf, nbuf, stdin); printf("pid: %d, ppid: %d\n", getpid(), getppid()); printf("buf: %s", buf); if(buf[0] == 0) {// EOF printf("end of getcmd\n"); return -1; } return 0; } int main(void) { static char buf[100]; int fd, r, ret; // Read and run input commands.

问题 I was about to write a shell with C language. Here is the source code below: #include <unistd.h> #include <stdio.h> #include <string.h> #include <sys/wait.h> #include <stdlib.h> int getcmd(char *buf, int nbuf) { memset(buf, 0, nbuf); fgets(buf, nbuf, stdin); printf("pid: %d, ppid: %d\n", getpid(), getppid()); printf("buf: %s", buf); if(buf[0] == 0) {// EOF printf("end of getcmd\n"); return -1; } return 0; } int main(void) { static char buf[100]; int fd, r, ret; // Read and run input commands.

问题 A few years ago, in the Windows environment, I did some testing, by letting multiple instances of CPU computation intensive + memory access intensive + I/O access intensive application run. I developed 2 versions: One is running under multi-processing, another is running under multi-threading. I found that the performance is much better for multi-processing. I read somewhere else (but I can't remember the site). Which states that the reason is that under multi-threading, they are "fighting"