[mpich-discuss] Hydra issues

[Scott Atchley]

No, the ring starts fast enough. It is connecting 1024 processes that  
is slow (allgatherv).

By contrast, Intel MPI launched in < 10 seconds.

Scott

On Aug 26, 2009, at 4:07 PM, Rusty Lusk wrote:

> I assume that you mean launching the MPD ring is slow.  Once the MPD  
> ring is up, launching should be quick.   The original idea was that  
> the MPD ring would be persistent across jobs, even from different  
> people, as long as the jobs used the same nodes.
>
> Rusty
>
> On Wednesday,Aug 26, 2009, at 2:45 PM, Scott Atchley wrote:
>
>> On Aug 26, 2009, at 3:39 PM, Pavan Balaji wrote:
>>
>>>>> 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).
>>>
>>> This works for me. We need to figure out how to make this portable  
>>> now.
>>>
>>> -- Pavan
>>
>> Thanks for your persistence (no pun intended).
>>
>> When running with 1,024 ranks, launching via MPD can take several  
>> minutes. I am assuming that hydra will launch in seconds.
>>
>> Scott
>