shared-memory

Where is shared memory belongs to ? Which means it is owned by each individual process like stack and heap. So, other program cannot able to access the stack of some other program. Or it is a common segment of memory which is used by any number of process. The below figure shows my question diagramatically. Figure 1: ----------------- ----------------- ----------------- | stack | | stack | | stack | | | | | | | | Shared m/y | --->| Shared m/y |<--- | Shared m/y | | | | | | | | | | heap | | | Heap | | | Heap | | | | | | | | | | Data segment | | | Data segment | | | Data segment | | | | | | | |

I'm performing analyses of time-series of simulations. Basically, it's doing the same tasks for every time steps. As there is a very high number of time steps, and as the analyze of each of them is independant, I wanted to create a function that can multiprocess another function. The latter will have arguments, and return a result. Using a shared dictionnary and the lib concurrent.futures, I managed to write this : import concurrent.futures as Cfut def multiprocess_loop_grouped(function, param_list, group_size, Nworkers, *args): # function : function that is running in parallel # param_list :

This code: shmop_delete(); shmop_close(); doesn't delete shared memory. An experiment: $shmid = @shmop_open(1234, 'a', 0, 0); var_dump($shmid); yields bool(false) of course. But $shmid = shmop_open(5678, 'c', 0644, 10); ... shmop_delete($shmid); shmop_close($shmid); ... $shmid = @shmop_open(5678, 'a', 0, 0); var_dump($shmid); yields int(157) Why not deleted yet? How can I delete shared memory? I'm running apache on windows 7. SHM is not natively available in Windows, so PHP tries to emulate it in its "thread safe resource manager" (TSRM) by using Windows File Mappings internally, which is an

I try to learn how to use shared memory pixmaps in the xcb library. Did any of you have experience with this and want to share example codes and/or information? This would be very helpful. Thanks After some research I found out how to use shared memory pixmaps in xcb. Here is my testcode: #include <stdlib.h> #include <stdio.h> #include <sys/ipc.h> #include <sys/shm.h> #include <xcb/xcb.h> #include <xcb/shm.h> #include <xcb/xcb_image.h> #define WID 512 #define HEI 512 int main(){ xcb_connection_t* connection; xcb_window_t window; xcb_screen_t* screen; xcb_gcontext_t gcontext; xcb_generic_event

I was wondering whether you could do multithreaded writes to a single file by using memory-mapped files , and making sure that two threads don't write to the same area (e.g. by interleaving fixed-size records), thus alleviating the need for synchronization at the application level, i.e. without using critical sections or mutexes in my code. However, after googling for a bit, I'm still not sure. This link from Microsoft says: First, there is an obvious savings of resources because both processes share both the physical page of memory and the page of hard disk storage used to back the memory

I am implementing a multi-threaded program in Java, where each thread is of a type class Node extends Thread . All these classes generate certain values which will be used by other classes. For main it's easy to get the values from the generated threads , but from within threads itself, how can I get the values on other threads ? //Start the threads from a list of objects for (int i = 0; i < lnode.size(); i++) { lnode.get(i).start(); } thanks If you do something like: class MyThreadRunnable implements Runnable { List<String> strings; MyThreadRunnable(List<String> strings) { this.strings =

I'm using multiprocessing to create sub-process to my application. I also share a dictionary between the process and the sub-process. Example of my code: Main process: from multiprocessing import Process, Manager manager = Manager() shared_dict = manager.dict() p = Process(target=mysubprocess, args=(shared_dict,)) p.start() p.join() print shared_dict my sub-process: def mysubprocess(shared_dict): shared_dict['list_item'] = list() shared_dict['list_item'].append('test') print shared_dict In both cases the printed value is : {'list_item': []} What could be the problem? Thanks Manager.dict will