Scott Atchley wrote:

Terry,

Are you testing on Linux? If so, which kernel?

No, I am running into issues on Solaris but Ollie's run of the test code on Linux seems to work fine.

--td

See the patch to iperf to handle kernel 2.6.21 and the issue that they had with usleep(0):

http://dast.nlanr.net/Projects/Iperf2.0/patch-iperf-linux-2.6.21.txt

Scott

On Aug 31, 2007, at 1:36 PM, Terry D. Dontje wrote:

Ok, I have an update to this issue.  I believe there is an
implementation difference of sched_yield between Linux and Solaris. If
I change the sched_yield in opal_progress to be a usleep(500) then my
program completes quite quickly.  I have sent a few questions to a
Solaris engineer and hopefully will get some useful information.

That being said, CT-6's implementation also used yield calls (note this actually is what sched_yield reduces down to in Solaris) and we did not
see the same degradation issue as with Open MPI.  I believe the reason
is because CT-6's SM implementation is not calling CT-6's version of
progress recursively and forcing all the unexpected to be read in before continuing. CT-6 also has a natural flow control in it's implementation
(ie it has a fixed set fifo for eager messages.

I believe both of these characteristics lend CT-6 to not being
completely killed by the yield differences.

--td


Li-Ta Lo wrote:

On Thu, 2007-08-30 at 12:45 -0400, terry.don...@sun.com wrote:


Li-Ta Lo wrote:



On Thu, 2007-08-30 at 12:25 -0400, terry.don...@sun.com wrote:




Li-Ta Lo wrote:





On Wed, 2007-08-29 at 14:06 -0400, Terry D. Dontje wrote:






hmmm, interesting since my version doesn't abort at all.







Some problem with fortran compiler/language binding? My C translation
doesn't have any problem.

[ollie@exponential ~]$ mpirun -np 4 a.out 10
Target duration (seconds): 10.000000, #of msgs: 50331, usec per msg:
198.684707







Did you oversubscribe? I found np=10 on a 8 core system clogged things
up sufficiently.





Yea, I used np 10 on a 2 proc, 2 hyper-thread system (total 4 threads).





Is this using Linux?



Yes.

Ollie


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