[ExM Users] [EXTERNAL] Re: Generating Blobs in Swift/T

Knight, Samuel sknigh at sandia.gov
Mon Jul 14 16:42:02 CDT 2014


Thanks for the speedy response.
We are currently building 0.5.0 from source.

I have three additional questions;

  1.  Is there a float -> int function? I crating a workaround by casting float -> string -> (parse on decimal) string -> int. It is wasteful, and it only works when there is no exponential component.
  2.  Is there a single, comprehensive place to read about the '@' directives? For example, I cannot determine the difference between '@dispatch=WORKER' and '@dispatch=LEAF' from the documentation I have found.
  3.  Is a roadmap posted online? It is relevant to my project to know about this programming-model's direction. It would be particularly helpful to know when 0.6.0 and 1.0 are planned for release and what will be added to the implementation.

Thank You,
Samuel Knight

From: Tim Armstrong <tim.g.armstrong at gmail.com<mailto:tim.g.armstrong at gmail.com>>
Date: Monday, July 14, 2014 at 2:08 PM
To: Justin M Wozniak <wozniak at mcs.anl.gov<mailto:wozniak at mcs.anl.gov>>
Cc: "exm-user at lists.mcs.anl.gov<mailto:exm-user at lists.mcs.anl.gov>" <exm-user at lists.mcs.anl.gov<mailto:exm-user at lists.mcs.anl.gov>>
Subject: [EXTERNAL] Re: [ExM Users] Generating Blobs in Swift/T

I just wanted to add that if you built the release from source you can safely comment out the offending line (line 2178 of tcl-adlb.c, I believe, if you are using the exm-0.5.0 release).  As Justin said, this made it into the release on accident and doesn't have any useful purpose.

Regards,
Tim


On Mon, Jul 14, 2014 at 4:05 PM, Justin M Wozniak <wozniak at mcs.anl.gov<mailto:wozniak at mcs.anl.gov>> wrote:
Hi

Sorry- that message is a debugging line that unfortunately made it into the release.  It is already removed from our trunk and will not be in the next release- you can just remove it from your source.

I will fix the blob doc issue now but feel free to post any additional questions here in the meantime...

    Justin


On 07/14/2014 03:52 PM, Knight, Samuel wrote:
Hello,

I am writing a program in Swift/T that generates blob objects inside a leaf function. Binary data is generated with a Swig-wrapped C function, and the blob construct is produced by making a list out of the pointer and length in the Tcl wrapper.

Here is a sample from my Tcl script:

proc c_initVect { s o } {
set len [ expr $s * [blobutils_sizeof_int32] ]
        set ptr [ blobutils_malloc $len ]
        initVect [blobutils_cast_to_int_ptr $ptr] $s $o # C leaf function

        return [ list [ blobutils_cast_to_int  $ptr] $len ] # creating the blob
}

When I run the program with this snippet, my output fills with 'uncache_blob' messages.

Here is an example:
uncache_blob: 67376368 4000 3uncache_blob: 67380384 4000 4
Which is the output from a program that generates 2 blobs with the function above.

The output is automatically generated by the runtime, and I have no control over when blobs are uncached.

I've traced that output to ADLB_Local_Blob_Free_Cmd function in src/tcl/adlb/tcl-adlb.c

For programs that allocate a large number of blobs, the output from the runtime becomes overwhelming, and I am starting to think my snippet is generating blobs incorrectly. So far, the only example I can find that generates blobs that are returned to Swift/T is a the fortran example from the leaf functions guide (Section 3.4 www.mcs.anl.gov/exm/local/guides/leaf.html<http://www.mcs.anl.gov/exm/local/guides/leaf.html>). There is a promising link in Section 3.3.3 of the leaf guide that explains blobs, but when I click on it I get a 403 error.

Is anyone aware of additional examples or tutorials that explain how to generate and manage blobs in Swift/T.

Thank you,
Samuel Knight



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Justin M Wozniak


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