[Mochi-devel] running mochi examples

[Latham, Robert J.]

On Mon, 2019-11-04 at 07:37 -0500, Abid Malik via mochi-devel wrote:
> 
> Hello,
> 
> I am trying to play with the mochi examples at 
> 
>   https://xgitlab.cels.anl.gov/sds/sds-examples.git
> 
> I am trying the example on summit:
> 
> /mercury/01_hello/01_hg_hello_server
> 
> How should I start the server/client? I am trying it on login2 node
> and trying to initiate it like:
> 
> ./01_hg_hello_server bmi+tcp://login2:1234

I see you are using spack.  If so, I think you would have had to go out
of your way to request the 'bmi' transport.  You probably built
libfabric.  You can find out for sure with 'spack find'

You tell margo (mercury, really) which protocol to use but the string
for "libfabric using the verbs provider" is a little odd:

"ofi+verbs;ofi_rxm://"

> and getting errors.
> 
> # NA -- Error -- /tmp/amalik/spack-stage/spack-stage-mercury-master-
> nbp34rmg6rkc2ayiqxxxuupamvmdusr7/spack-src/src/na/na.c:281
>  # NA_Initialize_opt(): Specified class name does not support
> requested protocol

This says mercury did not recognize 'bmi+tcp'.  You'd get the same
error if you requested "moon_rock".

I don't have a lot of guidance to offer you (yet).  I just got started
on summit a few days ago.  When I try to take the advice I gave you I
get an error, too:

$ jsrun -r1 -n1 ./margo-example-server  verbs
# NA -- Error -- /tmp/robl/spack-stage/spack-stage-mercury-master-
c6nwqortoqjsyviyinlg5t6sfay6wv7l/spack-src/src/na/na.c:279
 # NA_Initialize_opt(): Specified class name does not support requested
protocol

That's what we expect.  margo/mercury don't know what 'verbs'
is.  Instead, we need to tell margo/mercury to use OFI (libfabric):

$ jsrun -r1 -n1 ./margo-example-server "ofi+verbs;ofi_rxm://"
# NA -- Error -- /tmp/robl/spack-stage/spack-stage-mercury-master-
c6nwqortoqjsyviyinlg5t6sfay6wv7l/spack-src/src/na/na_ofi.c:1406
 # na_ofi_getinfo(): fi_getinfo() failed, rc: -61(No data available)

Uh, I'm still working on that one...

==rob