Re: [OMPI users] Strange TCP latency results on Amazon EC2

On Tue, Jan 10, 2012 at 10:02 AM, Roberto Rey wrote: > 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. - There are 3 types of instances that can use 10 GbE. Are you using

Re: [OMPI users] Strange TCP latency results on Amazon EC2

On Thu, Jan 12, 2012 at 16:10, Jeff Squyres wrote: > 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

Re: [OMPI users] Strange TCP latency results on Amazon EC2

With ifconfig I can only see one Ethernet card (eth0) as well as the loopback interface 2012/1/12 teng ma > 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

Re: [OMPI users] Strange TCP latency results on Amazon EC2

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 wrote: > Thanks for your reply! > > I'm

Re: [OMPI users] Strange TCP latency results on Amazon EC2

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

Re: [OMPI users] Strange TCP latency results on Amazon EC2

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

Re: [OMPI users] Strange TCP latency results on Amazon EC2

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

[OMPI users] Strange TCP latency results on Amazon EC2

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