Okay, we've dug a bit and talked a lot :-)
If you want to do this with the default mapping system, just add
"--use-hwthreads-cpus" so we use the hwthreads as independent processors.
Otherwise, you can only bind down to the core level since we aren't treating
the HTs inside each core as separate
A little more on this (since affinity is one of my favorite topics of late :-)
). See my blog entries about what we just did in the 1.7 branch (and SVN
trunk):
http://blogs.cisco.com/performance/taking-mpi-process-affinity-to-the-next-level/
http://blogs.cisco.com/performance/process-affinity-i
Thanks!
John
On 9/12/12 8:05 AM, Ralph Castain wrote:
On Sep 12, 2012, at 4:57 AM, "John R. Cary" wrote:
I do want in fact to bind first to one HT of each core
before binding to two HTs of one core. So that will
be possible in 1.7?
Yes - you can get a copy of the 1.7 nightly tarball and ex
On Sep 12, 2012, at 4:57 AM, "John R. Cary" wrote:
> I do want in fact to bind first to one HT of each core
> before binding to two HTs of one core. So that will
> be possible in 1.7?
Yes - you can get a copy of the 1.7 nightly tarball and experiment with it in
advance, if you like. You'll wa
I do want in fact to bind first to one HT of each core
before binding to two HTs of one core. So that will
be possible in 1.7?
ThxJohn
On 9/11/12 11:19 PM, Ralph Castain wrote:
Not entirely sure I know what you mean. If you are talking about running
without specifying binding, then it mak
Not entirely sure I know what you mean. If you are talking about running
without specifying binding, then it makes no difference - we'll run wherever
the OS puts us, so you would need to tell the OS not to use the virtual cores
(i.e., disable HT).
If you are talking about binding, then pre-1.7
Our code gets little benefit from using virtual cores (hyperthreading),
so when we run with mpiexec on an 8 real plus 8 virtual machine, we
would like to be certain that it uses only the 8 real cores.
Is there a way to do this with openmpi?
ThxJohn
