Re: asynchronous operation with poll()

[Jonathan Rosser <jonathan.rosser-gjMux1o1B1/QXOPxS62xeg@public.gmane.org>]

On 11/10/10 10:30, Andrea Gozzelino wrote:
> Hi Jonathan,
>
> I wrote down a test (latency and transfer speed) with RDMA.
> Server and client work with the same code and they change defined size
> buffers for n times (loop). In the makefile.txt, you can find an help to
> use the code.
>
> I tested Intel NetEffect NE020 E10G81GP cards with this code and I found
> minimum latency about 11 us,maximum transfer speed about 9,6 GBytes, CPU
> usage up to 90% on client side.
> The last value is not good for us.

Hi Andrea,

Thanks for the code. With the advice from Jason I have changed my test 
program to get reliable communication using 1Mbyte buffers. The CPU 
usage is less than 2% on both client and server for 10Gb throughput. I 
have Chelsio S310CR.

I find using the poll() approach more natural as I have experience with 
conventional sockets based programming before.

The rdma_client/rdma_server example programs from librdmacm were the 
easiest to start from and I have incrementally changed them from 
synchronous to asynchronous operation, and moved the internals of the 
high level functions in <rdma/rdma_verbs.h> into my own code piece by 
piece. The learning curve is very steep :)

I found this paper quite interesting 
www.systems.ethz.ch/research/awards/minimizingthehidden.pdf

Cheers,
Jonathan.


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