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Subject: Re: [OMPI devel] orte_default_hostfile
From: Ralph Castain (rhc_at_[hidden])
Date: 2008-12-15 12:05:43

<laugh> can't argue with that logic! I'll make the change and file the


On Dec 15, 2008, at 9:06 AM, Greg Watson wrote:

> Hi Ralph,
> I think mainly because it simplifies installation of ompi for PTP
> users. Since PTP uses the hostfile to display the system
> configuration, we're pretty much always going to have one (although
> PTP does work without it, feedback is more limited). It's much
> easier for people to add a list of hosts to a file, than have to go
> and add something to the param file as well (it's hard enough to get
> them to do the former correctly).
> Greg
> On Dec 15, 2008, at 1:51 PM, Ralph Castain wrote:
>> Can you help me understand something here? I'm not opposed to
>> making the change - just puzzled as to why the value of the default
>> hostfile name is of concern to Eclipse.
>> There is one reason not to set a default name - it causes us to
>> open and read that file, even though nobody ever put something in
>> it. Remember, we distribute and install an empty default hostfile
>> that contains instructions on how to build one, so it will always
>> exist. Since the name of the default hostfile can be set in the
>> default MCA param file, environment, or cmd line, there didn't seem
>> to be any real reason to define some special name.
>> It isn't a big deal, though, so I don't really care that much. But
>> I would like to understand why Eclipse cares so we can factor that
>> into any future thinking.
>> Ralph
>> On Dec 12, 2008, at 7:11 AM, Greg Watson wrote:
>>> From our perspective, it would be good if it could default to the
>>> old behavior (in 1.3 if possible).
>>> Thanks,
>>> Greg
>>> On Dec 8, 2008, at 11:42 AM, Ralph Castain wrote:
>>>> I don't think there was any overt thought given to it, at least
>>>> not on my part. I suspect it came about because (a) the wiki
>>>> defining hostfile behavior made no mention of the default value,
>>>> (b) I may have overlooked the prior default when rewriting that
>>>> code, and (c) since we now have default-hostfile as well as
>>>> hostfile, it could be I didn't default the name since it isn't
>>>> clear which one should get the default.
>>>> I honestly don't remember - this has been in the code base for a
>>>> really long time now.
>>>> I have no iron in this fire - as you know, all of our environs
>>>> here are managed. So I guess I'll throw it out there to the
>>>> community:
>>>> do we want --default-hostfile to have a default value?
>>>> Pros: it could be considered a continuation of 1.2's hostfile
>>>> behavior
>>>> Cons: we treat hostfile in a totally different way in 1.3. We now
>>>> have two hostfiles: a default that applies to all app_contexts,
>>>> and a hostfile that applies to only one app_context. It would
>>>> seem that the default-hostfile best aligns with the old
>>>> "hostfile" behavior, but could lead to some confusion in its new
>>>> usage.
>>>> Any preferences/thoughts?
>>>> Ralph
>>>> On Dec 5, 2008, at 9:15 AM, Greg Watson wrote:
>>>>> Hi,
>>>>> In 1.2.x, the rds_hostfile_path parameter pointed to openmpi-
>>>>> default-hostfile by default. This parameter has been replaced
>>>>> with orte_default_hostfile in 1.3, but now it defaults to
>>>>> <none>. Was there any particular reason for the default value to
>>>>> change?
>>>>> Greg
>>>>> _______________________________________________
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