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Subject: Re: [OMPI devel] Question on the members of ompi_crcp_bkmrk_pml_drain_message_ref_t and ompi_crcp_bkmrk_pml_traffic_message_ref_t
From: Joshua Hursey (jjhursey_at_[hidden])
Date: 2010-08-26 09:23:47


Ananda,

So I think the comments are just misleading/wrong here. So messages are grouped by signature/envelope of the message. The ompi_crcp_bkmrk_pml_drain_message_ref_t and ompi_crcp_bkmrk_pml_traffic_message_ref_t data structures describe the envelope and each have a list of 'msg_contents' that point to the unique information for each message (e.g., buffer, request, status) of the type ompi_crcp_bkmrk_pml_message_content_ref_t.

So the 'drain_message' and 'traffic_message' datatypes use the various integers to count the number of done/active/posted 'message_content' datatypes stored in the list that they are responsible for. The internals of crcp_bkmrk_pml.c use these counter values to quickly look up what needs to be drained or waited on instead of iterating through the list of all messages every time.

This was a technique to reduce both the memory footprint of the implementation and improve performance slightly. It looks like the comments were not updated to match the change. Sorry about that. I'll file a ticket to update those comments in the trunk and branches so I don't forget.
  https://svn.open-mpi.org/trac/ompi/ticket/2550

I hope that helps a bit.

Best,
Josh

On Aug 26, 2010, at 1:59 AM, <ananda.mudar_at_[hidden]> <ananda.mudar_at_[hidden]> wrote:

> Josh
>
> In the file ompi/mca/crcp/bkmrk/crcp_bkmrk_pml.h, I have a question on the way few of the members of the following structures are defined:
> ompi_crcp_bkmrk_pml_drain_message_ref_t
> ompi_crcp_bkmrk_pml_traffic_message_ref_t
>
> Under the definition of “ompi_crcp_bkmrk_pml_drain_message_ref_t”, based on the comments following members are better declared as Boolean variables however they are declared as integers. Is there any reason for not using Boolean type?
>
> /** Is this message complete WRT PML semantics?
> * true = message done on this side (send or receive)
> * false = message still in process (sending or receiving)
> */
> int done;
>
> /** Is the message actively being worked on?
> * true = Message is !done, and is in the progress cycle
> * false = Message is !done and is *not* in the progress cycle ( [send/recv]_init requests)
> */
> int active;
>
> /** Has this message been posted?
> * true = message was posted (Send or recv)
> * false = message was not yet posted.
> * Used when trying to figure out which messages the drain protocol needs to post, and
> * which message have already been posted for it.
> */
> int already_posted;
>
> I see that you have used bool type for similar members in ompi_crcp_bkmrk_pml_message_content_ref_t.
>
> Thanks
> Ananda
>
> Ananda B Mudar, PMP
> Senior Technical Architect
> Wipro Technologies
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------------------------------------
Joshua Hursey
Postdoctoral Research Associate
Oak Ridge National Laboratory
http://www.cs.indiana.edu/~jjhursey