On Wednesday 23 September 2009, Rahul Nabar wrote:
> On Tue, Aug 18, 2009 at 5:28 PM, Gerry Creager
wrote:
> > Most of that bandwidth is in marketing... Sorry, but it's not a high
> > performance switch.
>
> Well, how does one figure out what exactly is a "hih performance
> switch"?
IMHO 1G Eth
Rahul Nabar wrote:
On Tue, Aug 18, 2009 at 5:28 PM, Gerry Creager wrote:
Most of that bandwidth is in marketing... Sorry, but it's not a high
performance switch.
Well, how does one figure out what exactly is a "hih performance
switch"? I've found this an exceedingly hard task. Like the OP po
On Tue, Aug 18, 2009 at 5:28 PM, Gerry Creager wrote:
> Most of that bandwidth is in marketing... Sorry, but it's not a high
> performance switch.
Well, how does one figure out what exactly is a "hih performance
switch"? I've found this an exceedingly hard task. Like the OP posted
the Dell 6248
scaling
problem). I do not believe VASP has done the same.
Jim
-Original Message-
From: users-boun...@open-mpi.org [mailto:users-boun...@open-mpi.org] On
Behalf Of Gus Correa
Sent: Tuesday, August 18, 2009 6:43 PM
To: Open MPI Users
Subject: Re: [OMPI users] very bad parallel scaling of
Hi Craig, list
Independent of any issues with your GigE switch,
which you may need to address,
you may want to take a look at the performance of the default
OpenMPI MPI_Alltoall algorithm, which you say is a cornerstone of VASP.
You can perhaps try alternative algorithms for different message
siz
Most of that bandwidth is in marketing... Sorry, but it's not a high
performance switch.
Craig Plaisance wrote:
The switch we are using (Dell Powerconnect 6248) has a switching fabric
capacity of 184 Gb/s, which should be more than adequate for the 48
ports. Is this the same as backplane ban
Craig Plaisance wrote:
So is this a problem with the physical switch (we need a better switch)
or with the configuration of the switch (we need to configure the switch
or configure the os to work with the switch)?
You may want to look if you are dropping packets somewhere. You can look
at the
So is this a problem with the physical switch (we need a better switch)
or with the configuration of the switch (we need to configure the switch
or configure the os to work with the switch)?
Craig Plaisance wrote:
The switch we are using (Dell Powerconnect 6248) has a switching fabric
capacity of 184 Gb/s, which should be more than adequate for the 48
ports. Is this the same as backplane bandwidth?
Yes. If you are getting the behavior you describe, you are not getting
all that
The switch we are using (Dell Powerconnect 6248) has a switching fabric
capacity of 184 Gb/s, which should be more than adequate for the 48
ports. Is this the same as backplane bandwidth?
Craig Plaisance wrote:
mpich2 now and post the results. So, does anyone know what causes the
wild oscillations in the throughput at larger message sizes and higher
network traffic? Thanks!
Your switch can't handle this amount of traffic on its backplane. We
have seen this often in similar
I ran a test of tcp using NetPIPE and got throughput of 850 Mb/s at
message sizes of 128 Kb. The latency was 50 us. At message sizes above
1000 Kb, the throughput oscillated wildly between 850 Mb/s and values as
low as 200 Mb/s. This test was done with no other network traffic. I
then ran f
Craig Plaisance wrote:
Hi - I have compiled vasp 4.6.34 using the Intel fortran compiler 11.1
with openmpi 1.3.3 on a cluster of 104 nodes running Rocks 5.2 with two
quad core opterons connected by a Gbit ethernet. Running in parallel on
Latency of gigabit is likely your issue. Lower qualit
From: users-boun...@open-mpi.org [mailto:users-boun...@open-mpi.org] On
Behalf Of Jeff Squyres
Sent: Monday, August 17, 2009 9:24 PM
To: Open MPI Users
Cc: David Hibbitts
Subject: Re: [OMPI users] very bad parallel scaling of vasp using openmpi
You might want to run some performance testing of yo
You might want to run some performance testing of you TCP stacks and
the switch -- use a non-MPI application such as NetPIPE (or others --
google around) and see what kind of throughput you get. Try it
between individual server peers and then try running it simultaneously
between a bunch o
Hi - I have compiled vasp 4.6.34 using the Intel fortran compiler 11.1
with openmpi 1.3.3 on a cluster of 104 nodes running Rocks 5.2 with two
quad core opterons connected by a Gbit ethernet. Running in parallel on
one node (8 cores) runs very well, faster than any other cluster I have
run it
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