site_archiver@lists.apple.com Delivered-To: darwin-kernel@lists.apple.com On Sep 7, 2007, at 10:10 AM, Régis Duchesne wrote: Michael, 1) When a long-running task is being performed at an inappropriate priority, and it might be "nice" to let other threads have the CPU. In this case, I argue that the task should simply be moved to another thread that runs at an appropriate priority. So let's say I realize that one of my threads is too far ahead of the others in its computation. I want to slow it down, so I'll reduce its priority. Hold on a second here. = Mike _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.a... You are massively confusing the situation. In your original request, you did not describe what you were trying to do; you simply asked how to yield to the scheduler whilst in a kernel context. I assumed, incorrectly as it turned out, that you were trying to do this for one of the two reasons that I have outlined in e.g. my reply to Anton. You are, in fact, not doing this; instead you are trying to manage a long-running set of userland threads. I have detailed a set of co- ordination schemes that could be applied to your problem in another message. I really want to lower the priority of my thread _within_ its task (because the scheduling of that thread relative to the other in the same task is a decision that can be best made by my app). But the APIs that I find only allow me to do it system-wide. So as a workaround, I want a way to yield the processor, i.e. go at the end of the scheduling queue but with the exact same priority. This is not a good approach. Co-ordinate between your threads in order to keep them within an acceptable work delta of one another. You can do this in user space if the work is there - there is no need to have kernel code involved at all. This email sent to site_archiver@lists.apple.com