Re: NML channel question

[Will Shackleford <shackle-at-cme.nist.gov>]

Don McLane wrote:

> 
> 
> Should all channels to the same buffer need to have unique "proc" 
> names?  That is, whether they are in different processes or not.  Could 
> I create two channels, stat_1 and stat_2 like this:
> 
>     RCS_STAT_CHANNEL stat_1(fmt, "sts_buf", "main_proc", "rcshello.nml");
>     RCS_STAT_CHANNEL stat_2(fmt, "sts_buf", "main_proc", "rcshello.nml");
> 
> Normally, of course channels will be in different processes.  I'm just 
> writing a test program to see if I really understand what's going on.
> 
> Thanks in advance,
> 
> Don
> 
> 
> 


Two processes can use the same "proc" name, the only downside is that 
they have to be able to share all of the same process line settings. So 
you could not have one remote and the other local or one a master and 
the other not. One  rather serious problem is that with GLOBMEM and no 
bus-locking there are connection numbers that have to be unique for 
local processes and there is really no way to make them unique if you 
are sharing a process name. Since EMC only uses SHMEM and not GLOBMEM, 
and SHMEM doesn't ussually need unique connection numbers its not that 
big a problem for EMC. You might notice that the "xemc" process name is 
passed from xemc.cc ,yemc.cc, and emcsh.cc.

Just in case your interested . . .

A couple of weeks ago we were approached by some people using NML for an 
autonomous vehicle project.  The complained that they needed too many 
process lines in their NML configuration file. In response we added some 
checking for "default" lines in the config file and some code for 
automatically determining some settings, that eliminates the need for a 
lot of unique process lines. It hasn't been finalized yet  and there is 
no documentation but if you are really interested let me know and I'll 
try to get you some of the gory details.

-- Will











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William Penn Shackleford III			shackle-at-nist.gov
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