On Thu, Apr 10, 2008 at 10:06:40AM +0200, S?bastien Buisson wrote: > Let's consider that the internal bus of the machine is bigger enough so > that it will not be saturated. In that case, what will be the limiting > factor? memory? CPU? > I know that it depends on how many I/B cards are plugged in the machine, > but generally speaking, is the routing activity CPU or memory hungry? >
LNet routing is always memory hungry. Be sure to use 64-bit routers, because router buffers can only come from low system memory (i.e. ZONE_DMA and ZONE_NORMAL) which is usually 896M on 32-bit systems. Router CPU usage depends on network types. When routing between IB networks, router's CPU usage shall be minimal. But when a router is homed in a TCP network, it can be CPU hungry since host CPU must be involved in copying data received from the TCP network. Isaac _______________________________________________ Lustre-discuss mailing list [email protected] http://lists.lustre.org/mailman/listinfo/lustre-discuss
