smp

Ok, so I am reading about synchronization, and I read through various algorithms such as spinlocks, semaphores, and mutex to avoid race condition. However, these algorithms can't prevent race condition in SMP when multiple proceses access the data exactly at the same time. For example, suppose thread 1 in processor A runs lock(mutex1); withdraw(1000); unlock(mutex1); and thread 2 in processor B runs lock(mutex1); deposit(1000); deposit(1000); unlock(mutex1); When both threads run EXACTLY AT THE SAME TIME, both threads will be in critical section simultaneously. The only solution (should be in

Presumably there is a library or simple asm blob that can get me the number of the current CPU that I am executing on. Use sched_getcpu to determine the CPU on which the calling thread is running. See man getcpu (the system call) and man sched_getcpu (a library wrapper). However, note what it says: The information placed in cpu is only guaranteed to be current at the time of the call: unless the CPU affinity has been fixed using sched_setaffinity(2), the kernel might change the CPU at any time. (Normally this does not happen because the scheduler tries to minimize movements between CPUs to

I'm looking for a simple process-based parallel map for python, that is, a function parmap(function,[data]) that would run function on each element of [data] on a different process (well, on a different core, but AFAIK, the only way to run stuff on different cores in python is to start multiple interpreters), and return a list of results. Does something like this exist? I would like something simple , so a simple module would be nice. Of course, if no such thing exists, I will settle for a big library :-/ Flávio Amieiro I seems like what you need is the map method in multiprocessing.Pool() :

Is there a programmatic method to set CPU affinity for a process in c/c++ for the Linux operating system. You need to use sched_setaffinity(2) . For example, to run on CPUs 0 and 2 only: #define _GNU_SOURCE #include <sched.h> cpu_set_t mask; CPU_ZERO(&mask); CPU_SET(0, &mask); CPU_SET(2, &mask); result = sched_setaffinity(0, sizeof(mask), &mask); ( 0 for the first parameter means the current process, supply a PID if it's some other process you want to control). See also sched_getcpu(3) . Use sched_setaffinity at the process level, or pthread_attr_setaffinity_np for individual threads. In short