On Sep 3, 2010, at 9:38 AM, George Bosilca wrote: > I think you will have to revert this patch as the btl_bandwidth __IS__ > supposed to be in Mbs and not MBs. We usually talk about networks in Mbs > (there is a pattern in Ethernet 1G/10G, Myricom 10G).
This is why I shouldn't commit patches for others, and why I'm glad I pushed Scott to commit the other fixes himself... I'll revert; you, Scott, and Brice figure out what you want to do. > In addition the original design of the multi-rail was based on this > assumption, and the multi-rail handling code deal with these values (at that > level I don't think it really matters, but at least it needs consistent > values from all BTLs). > > However, going over the existing BTLs I can see that some BTLs do not > correctly set this value: > > BTL Bandwidth Auto-detect Status > Elan 2000 NO Correct > GM 250 NO Doubtful > MX 2000/10000 YES (Mbs) Correct (before the patch) > OFUD 800 NO Doubtful > OpenIB 2000/4000/8000 YES (Mbs) Correct (multiplied by the > active_width) > Portals 1000 NO Doubtful > SCTP 100 NO Conservative value (correct) > Self 100 XXX Correct (doesn't matter anyway) > SM 9000 NO Correct > TCP 100 NO Conservative value (correct) > UDAPL 225 NO Incorrect > > Some of these BTL values do not make sense, neither in Mbs or MBs. Here is a > list of such BTLs: OFUD, Portals, UDAPL. If the corresponding developers can > provide the default bandwidth (in Mbs) I will update their values. OFUD should be just like OpenFabrics. But I doubt anyone cares. Should we remove it? UDAPL intentionally hides that kind of stuff; I don't know if it's possible to get it. Rolf/Terry? > For SCTP, TCP I don't know how to detect it reliably in a portable way, so I > expect to let them set to this very conservative value. Moreover, the BTL TCP > is only used for multi-rail if the available high performance network allows > it, so it doesn't really matter. Some servers have 1GB and 10GB TCP, though... It might be worth having even a Linux-specific way to auto-detect, just for this use case (which is becoming more common -- 1GB LOM and a 10GB non-iWARP NIC). -- Jeff Squyres jsquy...@cisco.com For corporate legal information go to: http://www.cisco.com/web/about/doing_business/legal/cri/
