No Jira ticket yet, reason of the potential performance issue is straightforward, it's because all LNet NIs are linked on a plain list, and we need scan the whole list for each sending/receiving, it's not an issue for a few networks, but it could be problematic for hundreds or tens.
Liang On Aug 8, 2012, at 10:48 PM, Cory Spitz wrote: > Liang, > > What main stream perf. issue do you refer to? Is there a JIRA ticket > tracking it? > > Thanks, > -Cory > > On 08/08/2012 09:38 AM, Liang Zhen wrote: >> Hi, LNet reserved 32 bits for network number, so you can choose a very large >> network number if only have a few networks, but really create many networks >> will have some issues: >> - o2iblnd will pre-allocate memory resources for each network, so it will >> consume a lot of memory >> - Main stream LNet will have performance issue if there're many networks, >> for example, hundreds, although it's not difficult to fix this. >> >> Liang >> >> On Aug 8, 2012, at 10:23 PM, Rick Mohr wrote: >> >>> >>> I was curious what limitations exist for o2ib network numbers. Most of >>> the time I am dealing with o2ib0, o2ib1, etc. As as experiment, I tried >>> configuring a machine with o2ib1000, and that seemed to be OK. I >>> figured there must be some limit on how large the network number can >>> get, but after doing some searching, I have been unable to find any docs >>> that specify a limit. Does any know what the max network number is? >>> >>> -- >>> Rick Mohr >>> HPC Systems Administrator >>> National Institute for Computational Sciences >>> http://www.nics.tennessee.edu/ >>> >>> _______________________________________________ >>> Lustre-discuss mailing list >>> [email protected] >>> http://lists.lustre.org/mailman/listinfo/lustre-discuss >> >> _______________________________________________ >> Lustre-discuss mailing list >> [email protected] >> http://lists.lustre.org/mailman/listinfo/lustre-discuss _______________________________________________ Lustre-discuss mailing list [email protected] http://lists.lustre.org/mailman/listinfo/lustre-discuss
