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RE: Where's the parallelize step?

From: Costello, Roger L. <costello@mitre.org>
Date: Mon, 20 Apr 2009 09:00:25 -0400
To: "'xproc-dev@w3.org'" <xproc-dev@w3.org>
Message-ID: <9E51F88D5247B648908850C35A3BBB5003F245AA05@IMCMBX3.MITRE.ORG>
 
Hi Henry,

Ah, I see. Very clever.

Okay. I think that works.

Thanks! I'll add this to my tutorial.

/Roger

 
> -----Original Message-----
> From: Henry S. Thompson [mailto:ht@inf.ed.ac.uk] 
> Sent: Monday, April 20, 2009 8:49 AM
> To: Costello, Roger L.
> Cc: 'xproc-dev@w3.org'
> Subject: Re: Where's the parallelize step?
> 
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
> 
> Costello, Roger L. writes:
> 
> > I think there is a difference between:
> >
> >  - an XProc processor recognizing that some 
> >    steps can be run in parallel
> >
> >    versus
> >
> >  - a user creating an XML workflow, declaring  
> >    that "steps A, B, C can be run in parallel 
> >    with steps D, E, F"
> >
> >
> > The former is an XProc processor optimization activity. The latter
> > is a user modeling activity.
> >
> > I think that it is important for a user to be able to explicitly
> > state in an XProc document "These two workflow activities
> > (subpipelines) may be run in parallel." (Whether an XProc processor
> > executes the subpipelines in parallel or serially is an
> > implementation issue.)
> 
> Hmm, I'm worried we still have a disconnect.
> 
> If I write the following pipeline:
> 
>   <p:declare-step name="top">
>    <p:input port="i1" primary="false"/>
>    <p:input port="i2" primary="false"/>
> 
>    <p:output port="o1" primary="false">
>     <p:pipe step="sp1b" port="result"/>
>    </p:output>
> 
>    <p:output port="o2" primary="false">
>     <p:pipe step="sp2b" port="result"/>
>    </p:output>
> 
>    <p:... name="sp1a">
>     <p:input>
>      <p:pipe step="top" port="i1"/>
>     </p:input>
>    </p:...>
>     . . .
>    <p:... name="sp1b">
>     . . .
>    </p:...>
> 
>    <p:... name="sp2a">
>     <p:input>
>      <p:pipe step="top" port="i2"/>
>     </p:input>
>    </p:...>
>     . . .
>    <p:... name="sp2b">
>     . . .
>    </p:...>
> 
>   </p:declare-step>
> 
> do you think there is something that _prevents_ the two sub-pipelines
> - From running in parallel if you _don't_ say they can?  If so, I
> believe that's a misreading of the spec.
> 
> It is of course open to you to add
> 
>  <p:documentation>Note that the implicit subpipe beginning 
> with this step
>          and ending with step sp1b may run in parallel with
>          the implicit subpipe beginning with step 
> sp2a.</p:documentation>
> 
> to sp1a, but we don't need a language change to make that possible.
> 
> How is what you have in mind different from this?
> 
> ht
> - -- 
>        Henry S. Thompson, School of Informatics, University 
> of Edinburgh
>                          Half-time member of W3C Team
>       10 Crichton Street, Edinburgh EH8 9AB, SCOTLAND -- (44) 
> 131 650-4440
>                 Fax: (44) 131 651-1426, e-mail: ht@inf.ed.ac.uk
>                        URL: http://www.ltg.ed.ac.uk/~ht/
> [mail really from me _always_ has this .sig -- mail without 
> it is forged spam]
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Received on Monday, 20 April 2009 13:01:01 GMT

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