David Lawless wrote: > Alex, > > Have a question: > > Does or can the DCA mechanism copy small and even tiny packets > during low-level 'igb' device processing? Can IOAT/DCA become > involved in moving small packets from the kernel to user-space? > For UDP as well as TCP? > > The reason why we're so interested in the latest 82575 and 82576 > chips is the performance improvement potential. We deal with > extremely high volumes of 100-200 byte multicast UDP packets > which as far as I can tell has not been a major focus for the > new DMA controller functionality. My hope is that the second > generation of IOAT that includes cache coherent transfers can at > some point be applied to our data mix. Large packet off-loading > does not help in the slightest. > > Thanks, > > David > > > ------------------------------------------------------------------------ - > This SF.Net email is sponsored by the Moblin Your Move Developer's > challenge Build the coolest Linux based applications with Moblin SDK > & win great prizes Grand prize is a trip for two to an Open Source > event anywhere in the world > http://moblin-contest.org/redirect.php?banner_id=100&url=/ > _______________________________________________ > E1000-devel mailing list > E1000-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/e1000-devel
David, IOAT DMA offloading works for TCP only. It does not support UDP. Only large buffers are offloaded to DMA engine (> 4kB). DCA is a different feature that supports endpoint device to memory writes and it works regardless of transfer size. Regards, Maciej ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ E1000-devel mailing list E1000-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/e1000-devel
