On Thu, Mar 30, 2006 at 01:16:08PM +0100, Claus Reinke wrote:
It is not like inserting yields needs to be done much at all since we have progress guarentees, so we know the program is doing something and on any blocking call that could potentially take a while, the library will yield for you.
where do we get the progress guarantees from? do we need a "yield-analysis"? something that will automatically insert yields in the code after every n atomic steps, and complain if it cannot infer that some piece of code is atomic, but cannot insert a yield either? how much of the burden do you want to shift from the implementer to the programmer?
no, because there are only certain defined actions that can switch a thread's state from 'runnable' to 'not-runnable'. In order to meet the progress guarentee you just need to make sure that when the current thread switches from 'runnable' to 'not-runnable' that another thread is chosen. examples of these points would be: - calling a foreign concurrent import - waiting for input on a handle - waiting for a UNIX signal - changing thread priorities (possibly) in any case, the compiler need do nothing special in general, it is basically a library issue. John -- John Meacham - ⑆repetae.net⑆john⑈