Hi Aviv, Answers like yours make linux-il a fun list :-)
Aviv Greenberg wrote:
IOAT - its not a TCP offload engine. Intel's assumption is that the CPU is wasting a lot of cycles to copy data (from kernel to user and vv). IOAT is just a smart DMA engine that can move data (copy) without wasting the main CPU cycles. There are more details (cpu caching optimizationetc) but this is the basic idea.
When Ira asked me about it before it didn't ring any bells with me but now that you describe it I think I have a vague memory of Intel showing a research based on this at OLS 2005 where the conclusion was that it only benefits certain kinds of traffic and not others since, for example, for traffic made from many small packets (typical VoIP traffic for example), the cost associated with the memory management trickery required to pin and unpin the socket buffers costs more then the cycles saved due to the offloaded copy... thought I maybe gotten mixed with something else though.
Well, Google to the rescue as always... for those interested, I found a site about the Linux support of this thing here. It claims IOAT support is in the Linux kernel since 2.6.18. Not sure whether this is true or not.
http://www.linux-foundation.org/en/Net:I/OAT My 2c, Gilad ================================================================= To unsubscribe, send mail to [EMAIL PROTECTED] with the word "unsubscribe" in the message body, e.g., run the command echo unsubscribe | mail [EMAIL PROTECTED]
