Software IRQ Coalescing is required to improve network stack performance
in the RZ/G2L SoC family and the RZ/G3S SoC, i.e. the SoCs which use the
GbEth IP.
For the RZ/G2L, network throughput is comparable before and after this
change. CPU usage during TCP RX testing dropped by 6.5% and during UDP
RX testing dropped by 10%.
For the RZ/G2UL, network throughput is greatly increased by this change
(results obtained with iperf3):
* TCP TX: 2.9% more throughput
* TCP RX: 1.1% more throughput
* UDP TX: similar throughput
* UDP RX: 41500% 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.
Signed-off-by: Paul Barker <paul.barker.ct@xxxxxxxxxxxxxx>
---
drivers/net/ethernet/renesas/ravb.h | 1 +
drivers/net/ethernet/renesas/ravb_main.c | 4 ++++
2 files changed, 5 insertions(+)
diff --git a/drivers/net/ethernet/renesas/ravb.h b/drivers/net/ethernet/renesas/ravb.h
index 55a7a08aabef..ca7a66759e35 100644
--- a/drivers/net/ethernet/renesas/ravb.h
+++ b/drivers/net/ethernet/renesas/ravb.h
@@ -1078,6 +1078,7 @@ struct ravb_hw_info {
unsigned nc_queues:1; /* AVB-DMAC has RX and TX NC queues */
unsigned magic_pkt:1; /* E-MAC supports magic packet detection */
unsigned half_duplex:1; /* E-MAC supports half duplex mode */
+ unsigned needs_irq_coalesce:1; /* Requires SW IRQ Coalescing to achieve best performance */
};
struct ravb_private {
diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
index 661fd86899ac..7bb80608f260 100644
--- a/drivers/net/ethernet/renesas/ravb_main.c
+++ b/drivers/net/ethernet/renesas/ravb_main.c
@@ -2639,6 +2639,7 @@ static const struct ravb_hw_info gbeth_hw_info = {
.tx_counters = 1,
.carrier_counters = 1,
.half_duplex = 1,
+ .needs_irq_coalesce = 1,
};
static const struct of_device_id ravb_match_table[] = {
@@ -2983,6 +2984,9 @@ 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)
+ netdev_sw_irq_coalesce_default_on(ndev);
+
/* Network device register */
error = register_netdev(ndev);
if (error)
--
2.39.2
