Dear Dr. Sherrill, Thank you for your answer. Your explanation has been helpful.
It would seem that we need a discussion of the types of critical sections, > when they are used, and the difference between uniprocessor and symmetric > processing configurations. It'd be really helpful if someone can write about this in the documentation. This is a critical section which prevents thread context switches from > occurring while the dispatch level is not zero. This is generally used so > dispatching is deferred until the end of operations. It is also used so we > do not attempt to switch to another thread while in the middle of an > interrupt service routine Okay, so this is for the dispatch disable level, what about pin level? Is it like a boolean value in some way, true for level 1 and false for 0? On Sat, Dec 5, 2020 at 10:20 PM Joel Sherrill <j...@rtems.org> wrote: > > > On Sat, Dec 5, 2020, 12:15 AM Richi Dubey <richidu...@gmail.com> wrote: > >> I tried searching it on Google and RTEMS Documentation, but couldn't find >> anything that explains this. >> >> On Sat, Dec 5, 2020 at 11:34 AM Richi Dubey <richidu...@gmail.com> wrote: >> >>> Hi, >>> >>> Can someone please help me understand what is meant by level? What is >>> meant by the dispatch level and the pin level and other such definitions? I >>> just want a high-level idea of what we achieve by having levels and why we >>> need them. >>> >> > This is a critical section which prevents thread context switches from > occurring while the dispatch level is not zero. This is generally used so > dispatching is deferred until the end of operations. It is also used so we > do not attempt to switch to another thread while in the middle of an > interrupt service routine > > I would think this was documented somewhere but honestly I don't know > where. If someone has a suggestion , then we should add it. > > It would seem that we need a discussion of the types of critical sections, > when they are used, and the difference between uniprocessor and symmetric > processing configurations. > >> >>> Why do we have: >>> >>> _Assert( cpu_self->thread_dispatch_disable_level == 1 ); >>> >>> in some codes? >>> >> > This means that the software should not be called when dispatching is > disabled. This may mean not from an interrupt service routine although that > is by implication since you could have checked the interrupt nest level. > This can prevent some methods from being called from a user extension. > > --joel > >> _______________________________________________ >> devel mailing list >> devel@rtems.org >> http://lists.rtems.org/mailman/listinfo/devel > >
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