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71ff9e3df7
For the "fsl,etsec2" compatible models the driver currently supports 8 Tx and Rx DMA rings (aka HW queues). However, there are only 2 pairs of Rx/Tx interrupt lines, as these controllers are integrated in low power SoCs with 2 CPUs at most. As a result, there are at most 2 NAPI instances that have to service multiple Tx and Rx queues for these devices. This complicates the NAPI polling routine having to iterate over the mutiple Rx/Tx queues hooked to the same interrupt lines. And there's also an overhead at HW level, as the controller needs to service all the 8 Tx rings in a round robin manner. The combined overhead shows up for multi parallel Tx flows transmitted by the kernel stack, when the driver usually starts returning NETDEV_TX_BUSY leading to NETDEV WATCHDOG Tx timeout triggering if the Tx path is congested for too long. As an alternative, this patch makes the driver support only one Tx/Rx DMA ring per NAPI instance (per interrupt group or pair of Tx/Rx interrupt lines) by default. The simplified single queue polling routine (gfar_poll_sq) will be the default napi poll routine for the etsec2 devices too. Some adjustments needed to be made to link the Tx/Rx HW queues with each NAPI instance (2 in this case). The gfar_poll_sq() is already successfully used by older SQ_SG_MODE (single interrupt group) controllers. This patch fixes Tx timeout triggering under heavy Tx traffic load (i.e. iperf -c -P 8) for the "fsl,etsec2" (currently the only MQ_MG_MODE devices). There's also a significant memory footprint reduction by supporting 2 Rx/Tx DMA rings (at most), instead of 8, for these devices. Signed-off-by: Claudiu Manoil <claudiu.manoil@freescale.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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| .. | ||
| fs_enet | ||
| fec_main.c | ||
| fec_mpc52xx_phy.c | ||
| fec_mpc52xx.c | ||
| fec_mpc52xx.h | ||
| fec_ptp.c | ||
| fec.h | ||
| fsl_pq_mdio.c | ||
| gianfar_ethtool.c | ||
| gianfar_ptp.c | ||
| gianfar.c | ||
| gianfar.h | ||
| Kconfig | ||
| Makefile | ||
| ucc_geth_ethtool.c | ||
| ucc_geth.c | ||
| ucc_geth.h | ||
| xgmac_mdio.c | ||