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Subject: Re: [OMPI devel] RFC 1/1: improvements to the "notifier" framework and ORTE WDC
From: Abhishek Kulkarni (adkulkar_at_[hidden])
Date: 2010-03-29 19:53:51


On Mon, 29 Mar 2010, Sylvain Jeaugey wrote:

> Hi Ralph,
>
> For now, I think that yes, this is a unique identifier. However, in my
> opinion, this could be improved in the future replacing it by a unique
> string.
>
> Something like :
>
> #define ORTE_NOTIFIER_DEFINE_EVENT(eventstr, associated_text) {
> static int event = -1;
> if (OPAL_UNLIKELY(event == -1) {
> event = opal_sos_create_new_event(eventstr, associated_text);
> }
> ...<increase event counter>...
> }
>
> This would move the event numbering to the OPAL layer, making it transparent
> to the developper.
>

This is a good suggestion, but then I think we end up relying on run-time
generation of the event numbers and have to pay the extra cost of looking
up the event in a list/array/hash each time we log the event.

>From what I understand, and from the discussions that took place when this
proposal was first put up on the devel list, is that since the event
tracing hooks could lie in the critical path, we want the overhead to be
as low as possible. By manually defining the unique identifiers, we can
generate the event tracing macro at compile-time and have a minimal
tracing impact.

My 2¢ ofcourse.

Thanks
Abhishek

> Just my 2 cents ...
>
> Sylvain
>
> On Mon, 29 Mar 2010, Ralph Castain wrote:
>
>> Hi Abhishek
>> I'm confused by the WDC wiki page, specifically the part about the
>> new ORTE_NOTIFIER_DEFINE_EVENT macro. Are you saying
>> that I (as the developer) have to provide this macro with a unique
>> notifier id? So that would mean that ORTE/OMPI would
>> have to maintain a global notifier id counter to ensure it is unique?
>>
>> If so, that seems really cumbersome. Could you please clarify?
>>
>> Thanks
>> Ralph
>>
>> On Mar 29, 2010, at 8:57 AM, Abhishek Kulkarni wrote:
>>
>>
>> ======================================================================
>> [RFC 1/2]
>> ======================================================================
>>
>> WHAT: Merge improvements to the "notifier" framework from the OPAL
>> SOS
>>     and the ORTE WDC mercurial branches into the SVN trunk.
>>
>> WHY: Some improvements and interface changes were put into the ORTE
>>    notifier framework during the development of the OPAL SOS[1] and
>>    ORTE WDC[2] branches.
>>
>> WHERE: Mostly restricted to ORTE notifier files and files using the
>>      notifier interface in OMPI.
>>
>> TIMEOUT: The weekend of April 2-3.
>>
>> REFERENCE MERCURIAL REPOS:
>> * SOS development: http://bitbucket.org/jsquyres/opal-sos-fixed/
>> * WDC development: http://bitbucket.org/derbeyn/orte-wdc-fixed/
>>
>> ======================================================================
>>
>> BACKGROUND:
>>
>> The notifier interface and its components underwent a host of
>> improvements and changes during the development of the SOS[1] and
>> the
>> WDC[2] branches.  The ORTE WDC (Warning Data Capture) branch enables
>> accounting of events through the use of notifier interface, whereas
>> OPAL SOS uses the notifier interface by setting up callbacks to
>> relay
>> out logged events.
>>
>> Some of the improvements include:
>>
>> - added more severity levels.
>> - "ftb" notifier improvements.
>> - "command" notifier improvements.
>> - added "file" notifier component
>> - changes in the notifier modules selection
>> - activate only a subset of the callbacks
>> (i.e. any combination of log, help, log_peer)
>> - define different output media for any given callback (e.g.
>> log_peer
>> can be redirected to the syslog and smtp, while the show_help can be
>> sent to the hnp).
>> - ORTE_NOTIFIER_LOG_EVENT() (that accounts and warns about unusual
>> events)
>>
>> Much more information is available on these two wiki pages:
>>
>> [1] http://svn.open-mpi.org/trac/ompi/wiki/ErrorMessages
>> [2] http://svn.open-mpi.org/trac/ompi/wiki/ORTEWDC
>>
>> NOTE: This is first of a two-part RFC to bring the SOS and WDC
>> branches
>> to the trunk. This only brings in the "notifier" changes from the
>> SOS
>> branch, while the rest of the branch will be brought over after the
>> timeout of the second RFC.
>>
>> ======================================================================
>> _______________________________________________
>> devel mailing list
>> devel_at_[hidden]
>> http://www.open-mpi.org/mailman/listinfo.cgi/devel
>>
>>
>>
>>
>