| Message ID | 20240528150339.6791-7-paul.barker.ct@bp.renesas.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Geert Uytterhoeven |
| Headers | show |
| Series | Improve GbEth performance on Renesas RZ/G2L and related SoCs | expand |
diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c index e95e0b6e1fe6..dd92f074881a 100644 --- a/drivers/net/ethernet/renesas/ravb_main.c +++ b/drivers/net/ethernet/renesas/ravb_main.c @@ -2944,8 +2944,11 @@ static int ravb_probe(struct platform_device *pdev) if (info->nc_queues) netif_napi_add(ndev, &priv->napi[RAVB_NC], ravb_poll); - if (info->coalesce_irqs) + if (info->coalesce_irqs) { netdev_sw_irq_coalesce_default_on(ndev); + if (num_present_cpus() == 1) + dev_set_threaded(ndev, true); + } /* Network device register */ error = register_netdev(ndev);
NAPI Threaded mode (along with the previously enabled SW IRQ Coalescing) is required to improve network stack performance for single core SoCs using the GbEth IP (currently the RZ/G2L SoC family and the RZ/G3S SoC). This patch gives the following improvements during testing with iperf3. * RZ/G2UL: * TCP TX: +32% bandwidth (638Mbps -> 841Mbps) * TXP RX: +8.8% bandwidth (667Mbps -> 726Mbps) * UDP RX: +104% bandwidth (53Mbps -> 108Mbps) * RZ/G3S: * TCP TX: 29% bandwidth (529Mbps -> 681Mbps) * UDP RX: +1290% bandwidth (6.46Mbps -> 90Mbps) * RZ/Five: * UDP RX: Test no longer crashes (0 -> 20 Mbps) This patch gives the following reductions in performance in the same testing: * RZ/G2UL: * UDP TX: -7.5% bandwidth (594Mbps -> 549Mbps) * RZ/G3S: * UDP TX: -5% bandwidth (625Mbps -> 594Mbps) These losses are considered acceptable given the benefits shown above. If UDP TX bandwidth must be maximised for a particular use case, NAPI threaded mode can be disabled at runtime via sysfs writes. The improvement of UDP RX bandwidth for the single core SoCs (RZ/G2UL & RZ/G3S) is particularly critical. Signed-off-by: Paul Barker <paul.barker.ct@bp.renesas.com> Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru> --- Changes v3->v4: * Added Sergey's Reviewed-by tag. drivers/net/ethernet/renesas/ravb_main.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)