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From: =?utf-8?Q?Yannick_Duch=C3=AAne_=28Hibou57?=
 =?utf-8?Q?=29?=
 <yannick_duchene@yahoo.fr>
Newsgroups: comp.lang.ada
Subject: Re: Protected Objects And Many Processors
Date: Fri, 21 Jan 2011 20:31:49 +0100
Organization: Ada @ Home
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Date: 2011-01-21T20:31:49+01:00
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Le Fri, 21 Jan 2011 19:09:34 +0100, Georg Bauhaus  =

<rm.dash-bauhaus@futureapps.de> a =C3=A9crit:
> The presence of shared data almost always triggers the idea
> of employing protected objects, since these avoid the overhead
> of task switching.  But availability of computing hardware seems
> to renders this a weaker argument.

Yes, The =E2=80=9CAda 95 Rationales=E2=80=9D agree that efficiency is a =
key point:
http://www.adaic.org/resources/add_content/standards/95rat/rat95html/rat=
95-p2-9.html#1
Just that there is also semantic, protected objects are not just  =

efficient, they also Protects (so their name) against simultaneous acces=
s  =

to some data, i.e. one reading while another writing or one writing whil=
e  =

another is writing too.

If you feel there may be a better solution, we first should now what tha=
t  =

other solution could be (you did not say). You still need a  =

synchronization mechanism, aren't you ?

I feel I did not understood the argument about the hardware. Would you  =

like to be more explicit ?

> Will the program run just as well when written with only task
> objects if and when the number of available processors is
> sufficient, that is, C > N?
What was your criteria to decide one task here and there ? Use of taskin=
g  =

is directed by what the program is running, and we do not know anything =
 =

about it. Here as well, tell more if you would like to.

-- =

Si les chats miaulent et font autant de vocalises bizarres, c=E2=80=99es=
t pas pour  =

les chiens.

=E2=80=9CI am fluent in ASCII=E2=80=9D [Warren 2010]