Habilitado Intel® I / O Acceleration, mas sem bytes

Question

Eu habilitei o IOAT, mas parece que nenhum dado foi transferido usando o DMA para rede:

Eu habilitei o IOAT na bios. A CPU é a CPU Intel (R) Xeon (R) E5-2650 v2 @ 2.60GHz. Eu carreguei o módulo no Ubuntu 14.04 (3.11.0-26-genérico). Esta é a mensagem relevante no dmesg:

dmesg | grep ioat
[    7.314760] ioatdma: Intel(R) QuickData Technology Driver 4.00
[    7.315893] ioatdma 0000:00:04.0: irq 186 for MSI/MSI-X
[    7.317850] ioatdma 0000:00:04.1: irq 187 for MSI/MSI-X
[    7.318319] ioatdma 0000:00:04.2: irq 188 for MSI/MSI-X
[    7.323282] ioatdma 0000:00:04.3: irq 189 for MSI/MSI-X
[    7.323567] ioatdma 0000:00:04.4: irq 190 for MSI/MSI-X
[    7.323855] ioatdma 0000:00:04.5: irq 191 for MSI/MSI-X
[    7.324134] ioatdma 0000:00:04.6: irq 192 for MSI/MSI-X
[    7.324400] ioatdma 0000:00:04.7: irq 193 for MSI/MSI-X
[    7.324759] ioatdma 0000:40:04.0: irq 194 for MSI/MSI-X
[    7.325197] ioatdma 0000:40:04.1: irq 195 for MSI/MSI-X
[    7.325559] ioatdma 0000:40:04.2: irq 196 for MSI/MSI-X
[    7.325828] ioatdma 0000:40:04.3: irq 197 for MSI/MSI-X
[    7.326091] ioatdma 0000:40:04.4: irq 198 for MSI/MSI-X
[    7.326361] ioatdma 0000:40:04.5: irq 199 for MSI/MSI-X
[    7.326620] ioatdma 0000:40:04.6: irq 200 for MSI/MSI-X
[    7.326886] ioatdma 0000:40:04.7: irq 201 for MSI/MSI-X

Não encontrei nenhuma opção relacionada ao DCA na bios, mas esse é o dmesg | grep dca output:

dmesg | grep dca
[    2.216975] dca service started, version 1.12.1

Eu envio muitos pacotes UDP grandes

for i in seq 4; do netperf -H 192.168.56.2 -p 12865 -t UDP_STREAM -l 20 -C -c -- -m 65000 -s 16M -S 16M -R 1 &  done

mas / sys / class / dma / mostra que nenhum byte é transferido usando dma

/sys/class/dma# for i in 'seq 0 16'; do cat dma${i}chan0/bytes_transferred; done
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0