shared-memory

Let's say I create a semaphore. If I fork a bunch of child processes, will they all still use that same semaphore? Also, suppose I create a struct with semaphores inside and forked. Do all the child processes still use that same semaphore? If not, would storing that struct+semaphores in shared memory allow the child processes to use the same semaphores? I'm really confused about how my forked child processes can use the same semaphores. bdonlan Let's say I create a semaphore. If I fork a bunch of child processes, will they all still use that same semaphore? If you are using a SysV IPC

I have two different windows applications (two different people writing the code). One is Written in C++ and another one is in C#. I need some way how to share data in RAM between them. One must writes data and another one just reads the written data. What should I use to make it most effective and fast? Thanks. You can use Memory Mapped Files . Here is an article describing how to use them. Use a Windows File Mapping Object which allows you to share memory between processes. You can use Named Pipes . A named pipe is a named, one-way or duplex pipe for communication between the pipe server and

I want to fork multiple processes and then use a semaphore on them. Here is what I tried: sem_init(&sem, 1, 1); /* semaphore*, pshared, value */ . . . if(pid != 0){ /* parent process */ wait(NULL); /* wait all child processes */ printf("\nParent: All children have exited.\n"); . . /* cleanup semaphores */ sem_destroy(&sem); exit(0); } else{ /* child process */ sem_wait(&sem); /* P operation */ printf(" Child(%d) is in critical section.\n",i); sleep(1); *p += i%3; /* increment *p by 0, 1 or 2 based on i */ printf(" Child(%d) new value of *p=%d.\n",i,*p); sem_post(&sem); /* V operation */ exit(0

Consider the following scenario: Requirements: Intel x64 Server (multiple CPU-sockets => NUMA) Ubuntu 12, GCC 4.6 Two processes sharing large amounts of data over (named) shared-memory Classical producer-consumer scenario Memory is arranged in a circular buffer (with M elements) Program sequence (pseudo code): Process A (Producer): int bufferPos = 0; while( true ) { if( isBufferEmpty( bufferPos ) ) { writeData( bufferPos ); setBufferFull( bufferPos ); bufferPos = ( bufferPos + 1 ) % M; } } Process B (Consumer): int bufferPos = 0; while( true ) { if( isBufferFull( bufferPos ) ) { readData(

I have a 60GB SciPy Array (Matrix) I must share between 5+ multiprocessing Process objects. I've seen numpy-sharedmem and read this discussion on the SciPy list. There seem to be two approaches-- numpy-sharedmem and using a multiprocessing.RawArray() and mapping NumPy dtype s to ctype s. Now, numpy-sharedmem seems to be the way to go, but I've yet to see a good reference example. I don't need any kind of locks, since the array (actually a matrix) will be read-only. Now, due to its size, I'd like to avoid a copy. It sounds like the correct method is to create the only copy of the array as a

I have a very large (read only) array of data that I want to be processed by multiple processes in parallel. I like the Pool.map function and would like to use it to calculate functions on that data in parallel. I saw that one can use the Value or Array class to use shared memory data between processes. But when I try to use this I get a RuntimeError: 'SynchronizedString objects should only be shared between processes through inheritance when using the Pool.map function: Here is a simplified example of what I am trying to do: from sys import stdin from multiprocessing import Pool, Array def