On Tue, 23 Jun 2009, Sangjin Han wrote:
> > Are you running with MSI-X enabled? > > Yes, as well as RSS. > > > There is another patch we can add which enables DCA for data of > > received packets, but you need to run a test which actually accesses > > the data (usually not benchmarks) > > My microbechmark program actually touches all received bytes, in order > to emulate the cache behavior of minimal application layer. Does not > currently ixgbe 2.0.34.3 prefetches payload into caches even if I give > the driver a DCA=2 option? > > > Let me know if you're interested in applying this patch. > > I am really interested. Please let me apply the patch. Thanks. :-) if you're running the driver with DCA=2 as default, then you're already enabling DCA for data. do you have prefetchers enabled in your bios? you should turn off adjacent cache line prefetcher and hardware prefetch. If you have the prefetchers enabled it erases or makes worse performance with DCA enabled. This is because every memory access causes prefetches (shotgun style approach) as opposed to the adapter issuing DCA prefetches (more like surgical approach) Dell systems may not allow you to control prefetchers, not sure. Have you enabled header split mode using RxBufferMode parameter? This changes DCA behavior as well. Jesse ------------------------------------------------------------------------------ _______________________________________________ E1000-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/e1000-devel
