Re: [rtl] POSIX

yodaiken@chelm.cs.nmt.edu
Thu, 11 Mar 1999 13:34:24 -0700


On Thu, Mar 11, 1999 at 06:06:18PM +0100, Tomasz Motylewski wrote:
> Yes this is a very good idea. The problem with things like "RTC interrupt"
> waking up some linux process is that the wake up is often delayed until the
> next or even second clock tick (up to 20 ms). Even if the process uses
> something like:

The problem is also that Linux has a non-premptable kernel. So when a low priority task does, for
example, a long write, it will own the system until it runs out of buffers or until the write is done.

The best that the rt code can do is to improve the priority of the soft rt process and force linux to
do a reschedule at the next resched point. It is also, perhaps, possible for us to have pure user code
modules associated with a process that would be run immediately, but I don't think this would be nice.

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