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From: Graham E Fagg (fagg_at_[hidden])
Date: 2006-02-23 15:03:40


Thanks Konstantin,
  we are in the process of adding 3 more alltoall variants plus two
additional alltoallv methods by midweek next week, so hopefully we can
find the method that works best for your network. (two of the new methods
do slightly different request management and communication ordering to
reduce 'stress' on interconnect switches.)

Thanks,
   Graham.
-----------------------------------------------------------------------
Dr Graham E. Fagg | Distributed, Parallel and Meta-Computing
Innovative Computing Lab. PVM3.4, HARNESS, FT-MPI & Open MPI
Computer Science Dept | Suite 203, 1122 Volunteer Blvd,
University of Tennessee | Knoxville, Tennessee, USA. TN 37996-3450
Email: fagg_at_[hidden] | Phone:+1(865)974-5790 | Fax:+1(865)974-8296
Broken complex systems are always derived from working simple systems
-----------------------------------------------------------------------

  On Thu, 23 Feb 2006, Konstantin Kudin wrote:

> Hi all,
>
> I retested the very recent trunk with the skampi 4.1. The "alltoall"
> works quite nicely up to 7 dual Opterons, whereas bunch of
> isend+irecv's choke. There appear to be some "special" effects related
> to the 1Gbit setup we are using (problems with broadcom adapters?), and
> unless there is a clever "alltoall" scheme, things fall apart for large
> packets. Anyway, if "alltoall" gets pushed even further, that'd be very
> useful.
>
> What is the approximate time frame for officially releasing version
> 1.1 ? High performance "alltoall" will be of great use for a whole
> bunch of packages where the most challenging parallel part is
> distributed FFTs, which usually rely on "alltoall".
>
> Konstantin
>
> %%%%%
> openmpi-1.1a1r9108
>
> Columns: ncpu, average latency, std. deviation, ...
>
> message size: 16x4=64kbyte
>
> #/*@insyncol_MPI_Alltoall-nodes-long-SM.ski*/
> 2 275.1 1.6 8 275.1 1.6 8
> 3 1890.2 31.3 8 1890.2 31.3 8
> 4 3467.1 85.0 8 3467.1 85.0 8
> 5 5843.9 66.3 8 5843.9 66.3 8
> 6 8720.9 110.6 8 8720.9 110.6 8
> 7 9598.8 99.6 7 9598.8 99.6 7
> 8 11757.9 256.4 6 11757.9 256.4 6
> 9 13428.2 166.4 8 13428.2 166.4 8
> 10 14623.4 176.2 8 14623.4 176.2 8
> 11 16689.4 171.9 4 16689.4 171.9 4
> 12 18941.4 502.9 5 18941.4 502.9 5
> 13 20105.2 99.0 8 20105.2 99.0 8
> 14 22731.1 155.0 2 22731.1 155.0 2
> 15 123939.7 49248.4 8 123939.7 49248.4 8
> 16 142048.0 43888.8 8 142048.0 43888.8 8
>
> #/*@insyncol_MPI_Alltoall_Isend_Irecv-nodes-long-SM.ski*/
> 2 247.4 0.8 8 247.4 0.8 8
> 3 1861.8 10.1 8 1861.8 10.1 8
> 4 3158.4 24.5 8 3158.4 24.5 8
> 5 4270.0 75.0 2 4270.0 75.0 2
> 6 225351.5 12504.5 2 225351.5 12504.5 2
> 7 228399.5 14770.5 2 228399.5 14770.5 2
> 8 247087.5 14448.4 2 247087.5 14448.4 2
> 9 243806.7 3878.9 8 243806.7 3878.9 8
> 10 248353.0 6640.9 2 248353.0 6640.9 2
> 11 267541.5 5210.1 8 267541.5 5210.1 8
> 12 286600.1 1665.1 2 286600.1 1665.1 2
> 13 277546.5 4208.1 8 277546.5 4208.1 8
> 14 364208.9 98276.9 2 364208.9 98276.9 2
> 15 392139.0 101163.9 2 392139.0 101163.9 2
> 16 367182.1 97711.0 2 367182.1 97711.0 2
>
> #/*@insyncol_MPI_Alltoallv-nodes-long-SM.ski*/
> 2 279.8 1.0 8 279.8 1.0 8
> 3 1633.5 19.9 8 1633.5 19.9 8
> 4 2834.1 12.5 8 2834.1 12.5 8
> 5 4530.1 173.2 8 4530.1 173.2 8
> 6 147548.2 41749.4 8 147548.2 41749.4 8
> 7 248700.8 7621.9 8 248700.8 7621.9 8
> 8 261050.8 5618.6 8 261050.8 5618.6 8
> 9 256836.4 4441.5 8 256836.4 4441.5 8
> 10 274444.8 4019.0 8 274444.8 4019.0 8
> 11 275536.6 6338.7 8 275536.6 6338.7 8
> 12 282339.6 8411.8 8 282339.6 8411.8 8
> 13 303240.3 23093.0 8 303240.3 23093.0 8
> 14 399687.1 49633.4 8 399687.1 49633.4 8
> 15 359080.9 33852.4 8 359080.9 33852.4 8
> 16 337081.5 30155.5 8 337081.5 30155.5 8
>
>
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Thanks,
         Graham.
----------------------------------------------------------------------
Dr Graham E. Fagg | Distributed, Parallel and Meta-Computing
Innovative Computing Lab. PVM3.4, HARNESS, FT-MPI, SNIPE & Open MPI
Computer Science Dept | Suite 203, 1122 Volunteer Blvd,
University of Tennessee | Knoxville, Tennessee, USA. TN 37996-3450
Email: fagg_at_[hidden] | Phone:+1(865)974-5790 | Fax:+1(865)974-8296
Broken complex systems are always derived from working simple systems
----------------------------------------------------------------------