On Thu, Nov 8, 2012 at 9:01 AM, Jimmy Pan <dspjmt@xxxxxxxxx> wrote: > I understand how atomic operation work on unary core processors, I think it just disables the interrupt and dominate the cpu until it finished. > While, how do we implement this on multi processor computers? > Suppose cpu A is performing an atomic operation on variable a. At the same time, cpu B is also performing the operation on a. In such the result may be overwritten. > Of course we can use spinlocks, but on the atomic operation's behalf, how does it gurantee to prevent such case? > Can anyone explain the crux of it? Thanks. Basically you make use of machine specific instructions that will do that for you. In other words, get the datasheets of the specific system you intent to code on/for (I assume here you are refering to assembler level codes, as higher up you make use of the relevant libraries that does that for you). However, if you refer to the general case: You make use of critical areas bounded by the necessary lock(s), like semaphores, mutex locks, doors, message queues etc. that is described in details in several text books on the subject of concurrency/parallelism/distributed computing/etc. -- To unsubscribe from this list: send the line "unsubscribe linux-c-programming" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
