That might indicate the source of the bandwidth difference.
Open MPI uses the compiler supplied memcpy, which may or
may not be particularly fast for a given machine/architecture.
Scali could very well be using its own tuned memcpy.
On the hulk and tank systems at IU (16 core intel shared mem mach
I don't have access to the machine where my colleague ran. On other
machines, it appears that playing with eager or fragsize doesn't change
much... and, in any case, OMPI bandwidth is up around memcpy bandwidth.
So, maybe the first challenge is reproducing what he saw and/or getting
access to
George Bosilca wrote:
Something like this. We can play with the eager size too, maybe 4K is
too small.
george.
I guess I am curious why the larger buffer sizes work better? I am
curious because we ran into a similar issue on one of our platforms and
it turned out to be the non-temporal co
Something like this. We can play with the eager size too, maybe 4K is
too small.
george.
On Mar 18, 2009, at 06:43 , Terry Dontje wrote:
George Bosilca wrote:
The default values for the large message fragments are not
optimized for the new generation processors. This might be
something
George Bosilca wrote:
The default values for the large message fragments are not optimized
for the new generation processors. This might be something to
investigate, in order to see if we can have the same bandwidth as they
do or not.
Are you suggesting bumping up the btl_sm_max_send_size value
Jeff Squyres (jsquyres) wrote:
Re: [OMPI devel] OMPI vs Scali performance comparisons
I still think that the pml fast path fixes would be
good.
As do I. Again, I think one needs to go to the BTL sendi as soon as
possible after entering the PML, which raised those thorny
The default values for the large message fragments are not optimized
for the new generation processors. This might be something to
investigate, in order to see if we can have the same bandwidth as they
do or not.
george.
On Mar 17, 2009, at 18:23 , Eugene Loh wrote:
A colleague of mine
I still think that the pml fast path fixes would be good.
-jms
Sent from my PDA. No type good.
- Original Message -
From: devel-boun...@open-mpi.org
Sent: Tue Mar 17 18:23:18 2009
Subject: [OMPI devel] OMPI vs Scali performance comparisons
A colleague of mine ran some microkernels on
A colleague of mine ran some microkernels on an 8-way Barcelona box (Sun
x2200M2 at 2.3 GHz). Here are some performance comparisons with Scali.
The performance tests are modified versions of the HPCC pingpong
tests. The OMPI version is the trunk with my "single-queue" fixes...
otherwise, OMP
