benchmark program question

[Richard Hedges]

Hi Marty,

Have you looked at the parallel NetCDF version of the IOR benchmark?

- Richard


At 9:22 AM -0700 2/26/08, Marty Barnaby wrote:
>I'm new to the parallel NetCDF interface, and I don't have much 
>experience with NetCDF either. Because of new interest on our part, 
>we would like to have a straightforward, benchmark program to get 
>byte-rate metrics for writing to a Posix FS (chiefly, some large 
>Lustre deployments). I've had some reasonable experiences in this at 
>the MPI-IO level, achieving a sustained, average rate of 26 GB/s; 
>this writing to a single, shared file with an LFS stripe-count of 
>160. If anyone is interested, I could provide them with more 
>specifics.
>
>I can't find the benchmark-type code that I really need, though I've 
>been looking at the material under /test like 
>/test_double/test_write.c
>This I've compiled and executed successfully at the appropriate -np 4 level.
>
>There are three dynamics I would like to have that I can't see how to get.
>
>   1. Run on any number of processors. I'm sure this is simple, but I want to
>       know where the failure is when I attempt it.
>
>   2. Set the number of bytes appended to an open file in a single, atomic,
>       collective write operation. In my MPI-IO benchmark program I merely
>       got this number by having a buffer size on each processor, and the total
>       was the product of this times the number of processors. At the higher
>       level of PNetCDF I'm not sure which value I'm getting in the def_var
>       and put_var.
>
>   3. Be able to perform any number of equivalent, collective write operations,
>       appending to the same, open file. Simply a:
>
>       for ( i = 0; i < NUMRECS; i++ )
>
>       concept. This is basically what our scientific, simulation 
>applications do in their 'dump' mode.
>
>
>Thanks,
>Marty Barnaby


-- 



====================================================

Richard Hedges
Customer Support and Test - File Systems Project
Development Environment Group - Livermore Computing
Lawrence Livermore National Laboratory
7000 East Avenue, MS L-557
Livermore, CA	94551

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