[mpich-discuss] Hydra issues

Pavan Balaji balaji at mcs.anl.gov
Wed Aug 26 14:35:36 CDT 2009


No, this doesn't seem to be happening for me either. Just a simple test 
program run with two processes:

for (5 loops) { printf("foo\n"); sleep(1); }

  -- Pavan

On 08/26/2009 02:22 PM, Darius Buntinas wrote:
> This may be related:  On trunk, I get the output from rank 1
> immediately, but I only get rank 0 output when the app exits.
> 
> Maybe the buffer settings on the proxy aren't set correctly for rank 0's
> stdout socket?
> 
> -d
> 
> On 08/26/2009 01:55 PM, Scott Atchley wrote:
>> On Aug 26, 2009, at 1:38 PM, Dave Goodell wrote:
>>
>>> On Aug 26, 2009, at 9:19 AM, Dave Goodell wrote:
>>>
>>>> On Aug 26, 2009, at 8:58 AM, Scott Atchley wrote:
>>>>
>>>>> Ok, I was not patient enough. If I let it run, it eventually starts.
>>>>> The actual walltime is nearly the same as when I use proxies, but
>>>>> the stdout is delayed until the application completes.
>>>> I think I know why this happens.  It ought to be fixed once I finish
>>>> up some Hydra I/O work that was mostly done by one of our students
>>>> this summer.  The work is basically done and lives on a development
>>>> branch but it needs a little bit of cleanup and to be rebased onto
>>>> the current trunk.
>>> I was mistaken on this particular issue.  There was another buffering
>>> issue that we ran into during the student's work and I was thinking of
>>> that one.  There isn't any current hydra-side fix for this that I know
>>> of.
>>>
>>> However you could use one of the various workarounds for this, such as
>>> an LD_PRELOADed setvbuf call:
>>> http://lists.gnu.org/archive/html/bug-coreutils/2008-11/msg00164.html
>> This does not change the behavior.
>>
>> I am still stumped as to why there is no delay when using persistent
>> (launch-mode=2) versus a delay with no proxies (launch-mode=1).
>>
>> Scott

-- 
Pavan Balaji
http://www.mcs.anl.gov/~balaji


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