Dave, I also noticed that my previous understanding about 'preemptibility' was not correct.
Maybe the first question should be: Will every interrupt handler finally invoke dispatcher? Enlighten by your input, my current understanding for preemptibility is as follows: After an interrupt, it's possible that the interrupted dispatch unit will not be immediately redispatched. And if its time slice has not expired, we call this 'pre-empt'. On 10/29/07, Dave Barry <[EMAIL PROTECTED]> wrote: > > >However, if my program is also running disabled for external interrupts > and it uses CPU cycles heavily , how will the > >system 'pre-empt' my TCB? Or it cannot and just let my TCB starve other > users? I cannot figure out. > > Correct me if I'm wrong, but selective disablement is different than > preemptibility. An interrupt handler will normally return control to > the dispatcher, which may reorder its queue and dispatch a task other > than the one which was interrupted. However, that is not true if the > task is non-preemptible. I.e., it will be immediately redispatched > > -- Best Regards, Johnny Luo ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
