Here's an extract from the Networking section of the IDF. Towards the end is an interesting piece on GbE and offloaded TCP/IP. I have copied and pasted the off-loaded TCP/IP section (see below).
Intel Developer Forum, Fall 2001 Keynotes by Gadi Singer and Sean Maloney
intel.com
Finally, those storage transactions arrive at the file server itself, which contains an Intel pro 1000 T gigabit Ethernet adaptor card. Within the file server itself, again the driver is talking SCSI at one end of the file system, but on the other side it's actually talking to the gigabit Ethernet and doing the TCP/IP termination.
Now, that's quite a bit of computational load on the processor to terminate both the TCP/IP protocol as well as the iSCSI protocol. And if you look on the screen here you'll see we're using almost 100 percent of the processor computational capability, a little bit driving the video and a whole lot terminating these protocols.
Now, we have a second copy of this entire setup with another set of storage, 40 Cisco storage router, and another file server, the only difference being that in the second file server we've replaced the standard Intel pro gigabit Ethernet adaptor card with a TCP/IP gigabit Ethernet adaptor card. The difference in that second adaptor card is that it has additional silicon and intelligence that actually terminates the entire TCP/IP protocol. That offloads the protocol processing from the main processor and allows for faster operation.
SEAN MALONEY: I suppose if you're just making microprocessors, it's rather nice to consume the entire power with TCP/IP, right?
JOHN WAKERLY: Actually, we want to be able to leave a little bit left over for the storage processing; right? And the file system. And actually, if I show you on your left-hand side screen here, you'll see now the performance with the offloaded gigabit Ethernet adaptor. And there you see that the processor is cruising along with just about 15 percent CPU utilization running the video itself, and all that TCP processing, all the interrupt load that occurs during that processing is being handled by the adaptor card itself.
I might also add that the Intel silicon that is used to perform that offload is also used in a recently introduced Cisco product also to do TCP processing in a content switching application. So we're very, very happy with that technology.
SEAN MALONEY: Great. And in general, figuring out the TCP offload problem obviously is an essential part of making this thing useful.
JOHN WAKERLY: Absolutely, absolutely. |
