Hi, last week I've rewritten my btl-tcp component to improve several aspects, mainly no oversubscription of interfaces. I now have:
- the MCA parameter btl_tcp_disable_family={4|6} to force the use of a special address family at runtime - a working include/exclude list for interfaces (broken with the old design) - the ability to use different address families for different directions of communication, so ,--------------. ,---------------. | Host A | ---- IPv4 --------> | Host B | | RFC1918/NAT | | IPv4 public | | IPv6 | <--- IPv6 -------- | IPv6 | `--------------' `---------------' And probably something more ;) Yesterday, Thomas Peiselt, Christian Kauhaus and me (from the Cluster- & Metacomputing Group at the University of Jena) also did a first benchmark and we're proud to come up with very good news: IPv6 is not much slower than IPv4. Latency and bandwidth utilisation behave comparably, resulting in 111.17 MB/s with IPv4 versus 109.52 MB/s with IPv6 running IMB 2.3 PingPong over 1GigEthernet (in other words: IPv6 delivered 98.5% of the IPv4 bandwidth). I expect to confirm this tendency (less than 2% performance loss) by detailed benchmarking next week. Thomas is going to improve address family selection, so whenever it's possible, use IPv4 and by this squeeze out the last 1.5% of bandwidth ;) (my implementation tends to prefer IPv6, but I guess he'll fix it) Christian is very interested in testing. We have automatic builds, a cluster with IPv4/IPv6 and a traffic light turning from green to red whenever a build/test fails, so he's looking forward to provide testing facilities to the OMPI project, but I guess he'll raise his questions (mainly with respect to MTT) in a separate mail. I'm going to upload the new btl-tcp component to tmp/adi-ipv6 within the next days, it's currently only a branch in our local subversion which I'd like to merge before. -- mail: a...@thur.de http://adi.thur.de PGP: v2-key via keyserver Mit leerem Kopf nickt es sich leichter.