Thanks for the info.  Is this something that I could test, or could you send me 
a patch for one of the examples to crank them up to a big problem size?

Also, what type of computer / filesystem are you testing this on?  Straight 
local disk or what?

301MB/19 = 15.8 MB/sec, so I expect there is still some room for improvement.

But there is a lot of overhead too - indexing dof objects, assigning values, 
copies so as not to overload processor 0, etc..

I'll benchmark the raw underlying XDR I/O performance - how quickly Xdr can 
write say 500MB - so we know how much higher that number could reasonably go.

-Ben



On Nov 12, 2012, at 8:32 PM, David Knezevic <dkneze...@seas.harvard.edu> wrote:

> On 11/12/2012 09:23 PM, David Knezevic wrote:
>> On 11/06/2012 05:24 PM, Kirk, Benjamin (JSC-EG311) wrote:
>>> Dave, my ultimate fix for you will be extending this to write
>>> 
>>> for node…
>>>    for vec…
>>>      for var…
>>>        for comp…
>>> 
>>> or some permutation thereof, which will necessitate writing all the reduced 
>>> basis vectors to a single file, in order to get maximum performance.  I 
>>> assume that's OK with you?
>>> 
>> Hi Ben,
>> 
>> I've tried out the new RB IO on a problem with a "merged" .xdr file that
>> is 301MB --- previously I read this data in as many separate .xdr files
>> each of size 130kB.
>> 
>> In serial, it took about 22 seconds to do the read in the merged case
>> (i.e. RBEvaluation::read_in_vectors() took 22 seconds) vs. about 42
>> seconds in the "separated" case.
>> 
>> So it gives a 2x speedup, which is very helpful indeed. Though I recall
>> that a 30x speedup didn't seem out of the question --- are there
>> possibly some parameters (block sizes, etc, like before?) that I can try
>> tweaking to see if we can speed up the merged case further?
> 
> 
> P.S. It occurred to me that it's worth benchmarking 
> RBEvaluation::read_in_vectors in a bit more detail, and 19 of the 22 
> seconds is spent in System::read_serialized_vectors(). (The last 3 
> seconds in mostly due to the vector allocation.)
> 
> David
> 


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