[Swift-devel] Re: [Swft] Q about throttling

[Ioan Raicu]

Sorry to jump in on the discussion late.  Here are my thoughts on this 
issue:

Actually, what you are seeing is the completion rate of about 1/sec, but 
all 200 executors were busy... this is inherent to the length of time 
each task was taking, namely about 200 seconds on each executor, and we 
had 200 executors to process them, so we get 200/200, or 1/sec... so 
this was perfectly normal.  The part that is not normal, around time 
5000+ sec (where the red disappears, and only green is found), only 
about 90 executors were kept busy, and the Falkon queue length was 
relatively at 0... so this means that Swift was not submitting fast 
enough to keep all the executors busy.  If Swift submission rate would 
have been higher, I would have expected to see a little bit of red 
before each green bar throughout the graph.  Perhaps the Swift rate of 
submission was lower due to the dependencies in the workflow, but as I 
stated in a previous email, the red queue time should have continued 
until about task # 9600 (301 [first 3 stages] + 6800 [4th stage] + 2500 
[failed tasks])...

Ioan

Ben Clifford wrote:
> neat. when was the run made that generated those graphs?
>
> The submits seem to be going through at about 1/sec in the 1000..2000s 
> time range. Is that the bit that is the problem?
>
> On Thu, 21 Jun 2007, Ian Foster wrote:
>
>   
>> See this document for a set of three graphs that Ioan produced:
>>
>> http://people.cs.uchicago.edu/~iraicu/research/docs/MolDyn/100-Mol_MolDyn.pdf 
>>
>> The first is the same as Tibi's, I think. The second and third are new. I want
>> to have all three produced in a standard way for every application run.
>>
>> Ian.
>>
>>
>> Ben Clifford wrote:
>>     
>>> actually, the graph that Tibi showed, which I think is pretty much the same
>>> as the graph from Ioan's gui visualizer thing, would be interesting to see
>>> for the present MolDyn runs.
>>>
>>> It was interesting to look at when wondering about the bug Yong fixed last
>>> week.
>>>
>>> On Thu, 21 Jun 2007, Ian Foster wrote:
>>>
>>>   
>>>       
>>>> agreed
>>>>
>>>> Ben Clifford wrote:
>>>>     
>>>>         
>>>>> On Thu, 21 Jun 2007, Ian Foster wrote:
>>>>>
>>>>>         
>>>>>           
>>>>>> I'm gathering from this exchange that this is not possible?
>>>>>>             
>>>>>>             
>>>>> I have no idea. It doesn't seem to be documented.
>>>>>
>>>>> But the number one rule of tech support is don't take somebody else's
>>>>> partially solved problem. It would be good to see what is actually
>>>>> causing
>>>>> you to suspect that there's a throttling problem.
>>>>>
>>>>>         
>>>>>           
>>>>     
>>>>         
>>>   
>>>       
>>     
>
>   

-- 
============================================
Ioan Raicu
Ph.D. Student
============================================
Distributed Systems Laboratory
Computer Science Department
University of Chicago
1100 E. 58th Street, Ryerson Hall
Chicago, IL 60637
============================================
Email: iraicu at cs.uchicago.edu
Web:   http://www.cs.uchicago.edu/~iraicu
       http://dsl.cs.uchicago.edu/
============================================
============================================

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