DDIO and DCA can run at the same time if I recall. The only thing you have to watch out for is if the DCA is misconfigured in the BIOS.
Based on the fact that you have 0x1F in the tag field I am guessing you probably don't have too many sockets on the system. If you have multiple sockets it is possible to see some additional benefit from DCA. One thing you might want to try is changing the interrupt affinity for the queue and then pass a bit of traffic. You should see the tag value change when you move from one socket to another. - Alex On Tue, Nov 1, 2016 at 1:07 PM, Michał Purzyński <michalpurzyns...@gmail.com> wrote: > Did I ruin DDIO with DCA=2 parameter to X520? > > Looking at the driver code, I just enabled DCA instead. > >> On 1 Nov 2016, at 20:56, Alexander Duyck <alexander.du...@gmail.com> wrote: >> >> On Tue, Nov 1, 2016 at 12:04 PM, Michał Purzyński >> <michalpurzyns...@gmail.com> wrote: >>> Looking through some old posts on e1000 I found that one can detect if DCA >>> is enabled with ethregs. Are these registers per queue? Here, the X520 is >>> configured with a single queue and the highest bits are set only for >>> DCA_RXCTRL[000]. >> >> Yes, the registers are per queue. If I recall each queue can support >> a different DCA tag. >> >>> On X520 >>> >>> DCA_RXCTRL[000] 1f0002a0 >>> DCA_RXCTRL[001] 00001200 >>> >>> etc >>> >>> DCA_TXCTRL[000] 1f002220 >>> DCA_TXCTRL[001] 00002200 >>> >>> etc - 0's all the way down >>> >>> (second port, same card) >>> >>> DCA_RXCTRL[000] 1f0002a0 >>> DCA_RXCTRL[001] 00001200 >>> >>> Also zeros all the way on highest bits. >>> >>> There are no registers with DCA in name for X710 - what should I look for >>> instead? >> >> I don't believe the X710 supports DCA. It relies on DDIO which has >> been available for the last several CPU generations. >> >>> BTW, how is DCA different from DDIO? >> >> DCA is a precursor to DDIO. Basically the idea is to have the device >> include a special tag in DMA write transactions that indicates which >> socket the data is supposed to be written to. With DDIO it occurs >> automatically when the device is writing to the local socket. >> >> - Alex ------------------------------------------------------------------------------ Developer Access Program for Intel Xeon Phi Processors Access to Intel Xeon Phi processor-based developer platforms. With one year of Intel Parallel Studio XE. Training and support from Colfax. Order your platform today. http://sdm.link/xeonphi _______________________________________________ E1000-devel mailing list E1000-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/e1000-devel To learn more about Intel® Ethernet, visit http://communities.intel.com/community/wired
