With ifconfig I can only see one Ethernet card (eth0) as well as the loopback interface
2012/1/12 teng ma <t...@eecs.utk.edu> > Is it possible your EC2 cluster has another "unknown" crappy Ethernet > card(e.g. 1Gb > Ethernet card) . For small messages, they go through different paths in > NPtcp or MPI over NPmpi. > > Teng Ma > > > On Thu, Jan 12, 2012 at 10:28 AM, Roberto Rey <eros...@gmail.com> wrote: > >> Thanks for your reply! >> >> I'm using TCP BTL because I don't have any other option in Amazon with 10 >> Gbit Ethernet. >> >> I also tried with MPICH2 1.4 and I got 60 microseconds...so I am very >> confused about it... >> >> Regarding hyperthreading and process binding settings...I am using only >> one MPI process in each node (2 nodes for a clasical ping-pong latency >> benchmark). I don't know how it could affect on this test...but I could try >> anything that anyone suggest to me >> >> 2012/1/12 Jeff Squyres <jsquy...@cisco.com> >> >>> Hi Roberto. >>> >>> We've had strange reports of performance from EC2 before; it's actually >>> been on my to-do list to go check this out in detail. I made contact with >>> the EC2 folks at Supercomputing late last year. They've hooked me up with >>> some credits on EC2 to go check out what's happening, but the pent-up email >>> deluge from the Christmas vacation and my travel to the MPI Forum this week >>> prevented me from testing yet. >>> >>> I hope to be able to get time to test Open MPI on EC2 next week and see >>> what's going on. >>> >>> It's very strange to me that Open MPI is getting *better* than raw TCP >>> performance. I don't have an immediate explanation for that -- if you're >>> using the TCP BTL, then OMPI should be using TCP sockets, just like netpipe >>> and the others. >>> >>> You *might* want to check hyperthreading and process binding settings in >>> all your tests. >>> >>> >>> On Jan 12, 2012, at 7:04 AM, Roberto Rey wrote: >>> >>> > Hi again, >>> > >>> > Today I was trying with another TCP benchmark included in the hpcbench >>> suite, and with a ping-pong test I'm also getting 100us of latency. Then, I >>> tried with netperf and the same result.... >>> > >>> > So, in summary, I'm measuring TCP latency with messages size between >>> 1-32 bytes: >>> > >>> > Netperf over TCP -> 100us >>> > Netpipe over TCP (NPtcp) -> 100us >>> > HPCbench over TCP -> 100us >>> > Netpipe over OpenMPI (NPmpi) -> 60us >>> > HPCBench over OpenMPI -> 60us >>> > >>> > Any clues? >>> > >>> > Thanks a lot! >>> > >>> > 2012/1/10 Roberto Rey <eros...@gmail.com> >>> > Hi, >>> > >>> > I'm running some tests on EC2 cluster instances with 10 Gigabit >>> Ethernet hardware and I'm getting strange latency results with Netpipe and >>> OpenMPI. >>> > >>> > If I run Netpipe over OpenMPI (NPmpi) I get a network latency around >>> 60 microseconds for small messages (less than 2kbytes). However, when I run >>> Netpipe over TCP (NPtcp) I always get around 100 microseconds. For bigger >>> messages everything seems to be OK. >>> > >>> > I'm using the BTL TCP in OpenMPI, so I can't understand why OpenMPI >>> outperforms raw TCP performance for small messages (40us of difference). I >>> also have run the PingPong test from the Intel Media Benchmarks and the >>> latency results for OpenMPI are very similar (60us) to those obtained with >>> NPmpi >>> > >>> > Can OpenMPI outperform Netpipe over TCP? Why? Is OpenMPI doing any >>> optimization in BTL TCP? >>> > >>> > The results for OpenMPI aren't so good but we must take into account >>> the network virtualization overhead under Xen >>> > >>> > Thanks for your reply >>> > >>> > >>> > >>> > -- >>> > Roberto Rey Expósito >>> > _______________________________________________ >>> > users mailing list >>> > us...@open-mpi.org >>> > http://www.open-mpi.org/mailman/listinfo.cgi/users >>> >>> >>> -- >>> Jeff Squyres >>> jsquy...@cisco.com >>> For corporate legal information go to: >>> http://www.cisco.com/web/about/doing_business/legal/cri/ >>> >>> >>> _______________________________________________ >>> users mailing list >>> us...@open-mpi.org >>> http://www.open-mpi.org/mailman/listinfo.cgi/users >>> >> >> >> >> -- >> Roberto Rey Expósito >> >> _______________________________________________ >> users mailing list >> us...@open-mpi.org >> http://www.open-mpi.org/mailman/listinfo.cgi/users >> > > > > -- > | Teng Ma Univ. of Tennessee | > | t...@cs.utk.edu Knoxville, TN | > | http://web.eecs.utk.edu/~tma/ | > > _______________________________________________ > users mailing list > us...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/users > -- Roberto Rey Expósito
