"Daniel Kidger" <[EMAIL PROTECTED]> writes: > Bogdan, > > Parallel applications with lots of MPI traffic should run fine on a cluster > with large jiffies - just as long as the interconnect you use doesn't need to > take any interrupts. (Interrupts add hugely to the latency figure)
I know a lot of NICs misplaced interrupt mitigation adds to the latency figure. I know people who are serious about optimizing their hardware for mpi traffic poll for interrupts. There is fundamentally more work to do when you take an interrupt because you need to take a context switch. But cost of a context switch is in the order of microseconds, so while measurable taking an interrupt should not dramatically your latency numbers. Do you have any measurements to show that interrupts add hugely to latency figures, as opposed to a poor implementation of interrupts. This is important as polling for new packets has a very significant opportunity cost as it prevents you from get any other work done at the same time Eric _______________________________________________ Beowulf mailing list, [email protected] To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf
