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).
For the RZ/G2UL, network throughput is greatly increased by this change
(results obtained with iperf3) for all test cases except UDP TX:
* TCP TX: 30% more throughput
* TCP RX: 9.8% more throughput
* UDP TX: 9.7% less throughput
* UDP RX: 89% more throughput
For the RZ/G3S we see improvements in network throughput similar to the
RZ/G2UL.
The improvement of UDP RX bandwidth for the single core SoCs (RZ/G2UL &
RZ/G3S) is particularly critical. NAPI Threaded mode can be disabled at
runtime via sysfs for applications where UDP TX performance is a
priority.
Signed-off-by: Paul Barker <paul.barker.ct@xxxxxxxxxxxxxx>
---
drivers/net/ethernet/renesas/ravb_main.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
index 7bb80608f260..522df82524ff 100644
--- a/drivers/net/ethernet/renesas/ravb_main.c
+++ b/drivers/net/ethernet/renesas/ravb_main.c
@@ -2984,8 +2984,11 @@ static int ravb_probe(struct platform_device *pdev)
if (info->nc_queues)
netif_napi_add(ndev, &priv->napi[RAVB_NC], ravb_poll);
- if (info->needs_irq_coalesce)
+ if (info->needs_irq_coalesce) {
netdev_sw_irq_coalesce_default_on(ndev);
+ if (num_present_cpus() == 1)
+ dev_set_threaded(ndev, true);
+ }
/* Network device register */
error = register_netdev(ndev);
--
2.39.2
