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From: =?ISO-8859-1?Q?Hibou57_=28Yannick_Duch=EAne=29?=
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Subject: Re: Private or public task ?
Date: Tue, 9 Feb 2010 10:26:37 -0800 (PST)
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On 9 f=E9v, 16:20, Robert A Duff <bobd...@shell01.TheWorld.com> wrote:
> You should read all the stuff in the Real Time annex about priorities
> and ceilings and policies and whatnot.
>
> No, protected procedures and functions are not potentially blocking.
The misunderstanding was because I was misled on the meaning of
"blocking".
Jean-Pierre's words changed the situation (see his post).

> In your multiprocessor example, task#1 cannot procede
> into the protected procedure until task#2 lets go
> of it, but that's not blocking. =A0No lower-or-equal priority
> task can preempt task#1. =A0One possible implementation is
> that task#1 spins on the lock, which is OK because you
> made sure your protected procedure executes in a short
> bounded time.
I've later learned today about spin, but I still have to learn more
about it (that's an other area).

> Protected entries, on the other hand, are potentially blocking,
> because they put the task to sleep for an arbitrarily long time
> (until the barrier becomes True).
Unbounded