1 Reply Latest reply on Apr 18, 2009 11:05 AM by mark_h_@intel

    Is IOAT supported on 82571E NICs? What's the benefit to enabling it?



      I have IBM 3850m2's with 3 82571Es in them, I am using ESX 3.5 with NFS as my storage protocol, so I'm hitting the network pretty hard. THe cards are connected to a storage swtich running in a trunked config (2 gig each trunk).


      I'd like to know if these cards support IOAT and if they do what are the benefits of enabling it? Lower latency? Lower CPU utilization%?

      They are connected to Cisco 3750e  switches (2, stacked) if it makes any difference and running jumbo frames.


      This is try #4 to post this, I think Chrome is eating my attempts so I'm going via IE.

        • 1. Re: Is IOAT supported on 82571E NICs? What's the benefit to enabling it?

          Thanks for asking about Intel® I/O Acceleration Technology (Intel I/OAT). Intel® PRO/1000 PT and PF Server Adapters, which use the 82571 Ethernet controller do support Intel I/OAT. Unfortunately, ESX is not an officially supported operating system. However, according to the VMWare article, Details of What's New and Improved in VMware Infrastructure 3 version 3.5, "ESX Server 3.5 provides experimental support for Intel I/O Acceleration Technology (IOATv1)." I do not know enough to provide details on VMWare ESX support for Intel I/OAT to provide you with any more details beyond what I found in this article. Maybe someone else in this community or in the VMWare community can provide more help.


          The Intel support site has more details on Intel I/OAT requirements at http://www.intel.com/support/network/adapter/pro100/sb/CS-023725.htm.


          Any server that has a supported network connection, server chipset, and operating system can benefit from the features of Intel I/OAT, which enhance data acceleration across the computing platform:

          • Intel® QuickData Technology enables data copy by the chipset instead of the CPU, to move data more efficiently through the server and provide fast, scalable, and reliable throughput.
          • Direct Cache Access (DCA) allows a capable I/O device, such as a network controller, to place data directly into CPU cache, reducing cache misses and improving application response times.
          • Extended Message Signaled Interrupts (MSI-X) distributes I/O interrupts to multiple CPUs and cores, for higher efficiency, better CPU utilization, and higher application performance.
          • Receive Side Coalescing (RSC)aggregates packets from the same TCP/IP flow into one larger packet, reducing per-packet processing costs for faster TCP/IP processing.
          • Low Latency Interrupts tune interrupt interval times depending on the latency sensitivity of the data, using criteria such as port number or packet size, for higher processing efficiency.


          For anyone interested in reading more about Intel® I/O Acceleration Technology, you can find out more at http://www.intel.com/network/connectivity/vtc_ioat.htm.