[PATCH 0/5] Fix GBETH TX scheduling policy for RZ/{V2H, V2N, G3E, T2H, N2H}

[PATCH 0/5] Fix GBETH TX scheduling policy for RZ/{V2H, V2N, G3E, T2H, N2H}

[Ovidiu Panait]

This series switches the GBETH TX scheduling policy to
Weighted-Round-Robin (WRR) on RZ/V2H, RZ/V2N, RZ/G3E, RZ/T2H and RZ/N2H
SoCs.

Since the GBETH nodes don't currently specify a TX scheduling policy,
stmmac falls back to Strict Priority. In that configuration the highest
priority queue gets all the traffic and starves the others under load.

Under sustained UDP TX load with multiple data streams, this starvation
triggers adapter resets due to TX queue timeouts:

  iperf3 -c <ip> -i0 -t60 --bind-dev end0 -u -b0 -P4
  end0: NETDEV WATCHDOG: CPU: 1: transmit queue 1 timed out 5228 ms
  end0: Reset adapter.

Investigation showed that only the highest priority queue advances while
the others stall for more than 5 seconds, causing the netdev watchdog
reset.

Ovidiu Panait (5):
  arm64: dts: renesas: r9a09g057: Switch GBETH TX queue scheduling to
    WRR
  arm64: dts: renesas: r9a09g056: Switch GBETH TX queue scheduling to
    WRR
  arm64: dts: renesas: r9a09g047: Switch GBETH TX queue scheduling to
    WRR
  arm64: dts: renesas: r9a09g077: Switch GBETH TX queue scheduling to
    WRR
  arm64: dts: renesas: r9a09g078: Switch GBETH TX queue scheduling to
    WRR

 arch/arm64/boot/dts/renesas/r9a09g047.dtsi | 10 ++++++++
 arch/arm64/boot/dts/renesas/r9a09g056.dtsi | 10 ++++++++
 arch/arm64/boot/dts/renesas/r9a09g057.dtsi | 10 ++++++++
 arch/arm64/boot/dts/renesas/r9a09g077.dtsi | 27 ++++++++++++++++++++++
 arch/arm64/boot/dts/renesas/r9a09g087.dtsi | 27 ++++++++++++++++++++++
 5 files changed, 84 insertions(+)

-- 
2.34.1

[PATCH 1/5] arm64: dts: renesas: r9a09g057: Switch GBETH TX queue scheduling to WRR

[Ovidiu Panait]

The GBETH ethernet nodes don't specify a TX scheduling policy, so stmmac
falls back to Strict Priority. In this configuration the queue with the
highest priority gets all the traffic, starving the others under load.

Under sustained UDP TX load with multiple data streams, this starvation
triggers spurious adapter resets due to TX queue timeouts:

  iperf3 -c <ip> -i0 -t60 --bind-dev end0 -u -b0 -P4
  end0: NETDEV WATCHDOG: CPU: 1: transmit queue 1 timed out 5228 ms
  end0: Reset adapter.

Investigation shows that only the highest priority queue is advancing
while the others stall for more than 5 seconds, causing a netdev watchdog
reset.

Switch the TX scheduling policy to Weighted-Round-Robin (WRR) so that
traffic is processed across all queues, eliminating the stalls.

Fixes: 050ee38d0002 ("arm64: dts: renesas: r9a09g057: Add GBETH nodes")
Signed-off-by: Ovidiu Panait <ovidiu.panait.rb@renesas.com>
---
 arch/arm64/boot/dts/renesas/r9a09g057.dtsi | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/arch/arm64/boot/dts/renesas/r9a09g057.dtsi b/arch/arm64/boot/dts/renesas/r9a09g057.dtsi
index 639693d464a7..188ce9f9c7c2 100644
--- a/arch/arm64/boot/dts/renesas/r9a09g057.dtsi
+++ b/arch/arm64/boot/dts/renesas/r9a09g057.dtsi
@@ -1715,23 +1715,28 @@ queue3 {
 
 			mtl_tx_setup0: tx-queues-config {
 				snps,tx-queues-to-use = <4>;
+				snps,tx-sched-wrr;
 
 				queue0 {
+					snps,weight = <0x10>;
 					snps,dcb-algorithm;
 					snps,priority = <0x1>;
 				};
 
 				queue1 {
+					snps,weight = <0x12>;
 					snps,dcb-algorithm;
 					snps,priority = <0x2>;
 				};
 
 				queue2 {
+					snps,weight = <0x14>;
 					snps,dcb-algorithm;
 					snps,priority = <0x4>;
 				};
 
 				queue3 {
+					snps,weight = <0x18>;
 					snps,dcb-algorithm;
 					snps,priority = <0x8>;
 				};
@@ -1816,23 +1821,28 @@ queue3 {
 
 			mtl_tx_setup1: tx-queues-config {
 				snps,tx-queues-to-use = <4>;
+				snps,tx-sched-wrr;
 
 				queue0 {
+					snps,weight = <0x10>;
 					snps,dcb-algorithm;
 					snps,priority = <0x1>;
 				};
 
 				queue1 {
+					snps,weight = <0x12>;
 					snps,dcb-algorithm;
 					snps,priority = <0x2>;
 				};
 
 				queue2 {
+					snps,weight = <0x14>;
 					snps,dcb-algorithm;
 					snps,priority = <0x4>;
 				};
 
 				queue3 {
+					snps,weight = <0x18>;
 					snps,dcb-algorithm;
 					snps,priority = <0x8>;
 				};
-- 
2.34.1

[PATCH 2/5] arm64: dts: renesas: r9a09g056: Switch GBETH TX queue scheduling to WRR

[Ovidiu Panait]

The GBETH ethernet nodes don't specify a TX scheduling policy, so stmmac
falls back to Strict Priority. In this configuration the queue with the
highest priority gets all the traffic, starving the others under load.

Under sustained UDP TX load with multiple data streams, this starvation
triggers spurious adapter resets due to TX queue timeouts:

  iperf3 -c <ip> -i0 -t60 --bind-dev end0 -u -b0 -P4
  end0: NETDEV WATCHDOG: CPU: 1: transmit queue 1 timed out 5228 ms
  end0: Reset adapter.

Investigation shows that only the highest priority queue is advancing
while the others stall for more than 5 seconds, causing a netdev watchdog
reset.

Switch the TX scheduling policy to Weighted-Round-Robin (WRR) so that
traffic is processed across all queues, eliminating the stalls.

Fixes: c8c8a57c5b40 ("arm64: dts: renesas: r9a09g056: Add GBETH nodes")
Signed-off-by: Ovidiu Panait <ovidiu.panait.rb@renesas.com>
---
 arch/arm64/boot/dts/renesas/r9a09g056.dtsi | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/arch/arm64/boot/dts/renesas/r9a09g056.dtsi b/arch/arm64/boot/dts/renesas/r9a09g056.dtsi
index 76fa34ff3d07..77c2221a9e2a 100644
--- a/arch/arm64/boot/dts/renesas/r9a09g056.dtsi
+++ b/arch/arm64/boot/dts/renesas/r9a09g056.dtsi
@@ -1585,23 +1585,28 @@ queue3 {
 
 			mtl_tx_setup0: tx-queues-config {
 				snps,tx-queues-to-use = <4>;
+				snps,tx-sched-wrr;
 
 				queue0 {
+					snps,weight = <0x10>;
 					snps,dcb-algorithm;
 					snps,priority = <0x1>;
 				};
 
 				queue1 {
+					snps,weight = <0x12>;
 					snps,dcb-algorithm;
 					snps,priority = <0x2>;
 				};
 
 				queue2 {
+					snps,weight = <0x14>;
 					snps,dcb-algorithm;
 					snps,priority = <0x4>;
 				};
 
 				queue3 {
+					snps,weight = <0x18>;
 					snps,dcb-algorithm;
 					snps,priority = <0x8>;
 				};
@@ -1686,23 +1691,28 @@ queue3 {
 
 			mtl_tx_setup1: tx-queues-config {
 				snps,tx-queues-to-use = <4>;
+				snps,tx-sched-wrr;
 
 				queue0 {
+					snps,weight = <0x10>;
 					snps,dcb-algorithm;
 					snps,priority = <0x1>;
 				};
 
 				queue1 {
+					snps,weight = <0x12>;
 					snps,dcb-algorithm;
 					snps,priority = <0x2>;
 				};
 
 				queue2 {
+					snps,weight = <0x14>;
 					snps,dcb-algorithm;
 					snps,priority = <0x4>;
 				};
 
 				queue3 {
+					snps,weight = <0x18>;
 					snps,dcb-algorithm;
 					snps,priority = <0x8>;
 				};
-- 
2.34.1

[PATCH 3/5] arm64: dts: renesas: r9a09g047: Switch GBETH TX queue scheduling to WRR

[Ovidiu Panait]

The GBETH ethernet nodes don't specify a TX scheduling policy, so stmmac
falls back to Strict Priority. In this configuration the queue with the
highest priority gets all the traffic, starving the others under load.

Under sustained UDP TX load with multiple data streams, this starvation
triggers spurious adapter resets due to TX queue timeouts:

  iperf3 -c <ip> -i0 -t60 --bind-dev end0 -u -b0 -P4
  end0: NETDEV WATCHDOG: CPU: 1: transmit queue 1 timed out 5228 ms
  end0: Reset adapter.

Investigation shows that only the highest priority queue is advancing
while the others stall for more than 5 seconds, causing a netdev watchdog
reset.

Switch the TX scheduling policy to Weighted-Round-Robin (WRR) so that
traffic is processed across all queues, eliminating the stalls.

Fixes: 41ffbb1c42d3 ("arm64: dts: renesas: r9a09g047: Add GBETH nodes")
Signed-off-by: Ovidiu Panait <ovidiu.panait.rb@renesas.com>
---
 arch/arm64/boot/dts/renesas/r9a09g047.dtsi | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/arch/arm64/boot/dts/renesas/r9a09g047.dtsi b/arch/arm64/boot/dts/renesas/r9a09g047.dtsi
index 73757e8e2197..060405d4a2dd 100644
--- a/arch/arm64/boot/dts/renesas/r9a09g047.dtsi
+++ b/arch/arm64/boot/dts/renesas/r9a09g047.dtsi
@@ -1913,23 +1913,28 @@ queue3 {
 
 			mtl_tx_setup0: tx-queues-config {
 				snps,tx-queues-to-use = <4>;
+				snps,tx-sched-wrr;
 
 				queue0 {
+					snps,weight = <0x10>;
 					snps,dcb-algorithm;
 					snps,priority = <0x1>;
 				};
 
 				queue1 {
+					snps,weight = <0x12>;
 					snps,dcb-algorithm;
 					snps,priority = <0x2>;
 				};
 
 				queue2 {
+					snps,weight = <0x14>;
 					snps,dcb-algorithm;
 					snps,priority = <0x4>;
 				};
 
 				queue3 {
+					snps,weight = <0x18>;
 					snps,dcb-algorithm;
 					snps,priority = <0x8>;
 				};
@@ -2013,23 +2018,28 @@ queue3 {
 
 			mtl_tx_setup1: tx-queues-config {
 				snps,tx-queues-to-use = <4>;
+				snps,tx-sched-wrr;
 
 				queue0 {
+					snps,weight = <0x10>;
 					snps,dcb-algorithm;
 					snps,priority = <0x1>;
 				};
 
 				queue1 {
+					snps,weight = <0x12>;
 					snps,dcb-algorithm;
 					snps,priority = <0x2>;
 				};
 
 				queue2 {
+					snps,weight = <0x14>;
 					snps,dcb-algorithm;
 					snps,priority = <0x4>;
 				};
 
 				queue3 {
+					snps,weight = <0x18>;
 					snps,dcb-algorithm;
 					snps,priority = <0x8>;
 				};
-- 
2.34.1

[PATCH 4/5] arm64: dts: renesas: r9a09g077: Switch GBETH TX queue scheduling to WRR

[Ovidiu Panait]

The GBETH ethernet nodes don't specify a TX scheduling policy, so stmmac
falls back to Strict Priority. In this configuration the queue with the
highest priority gets all the traffic, starving the others under load.

Under sustained UDP TX load with multiple data streams, this starvation
triggers spurious adapter resets due to TX queue timeouts:

  iperf3 -c <ip> -i0 -t60 --bind-dev end0 -u -b0 -P4
  end0: NETDEV WATCHDOG: CPU: 1: transmit queue 1 timed out 5228 ms
  end0: Reset adapter.

Investigation shows that only the highest priority queue is advancing
while the others stall for more than 5 seconds, causing a netdev watchdog
reset.

Switch the TX scheduling policy to Weighted-Round-Robin (WRR) so that
traffic is processed across all queues, eliminating the stalls.

Fixes: 394c1e24a4cf ("arm64: dts: renesas: r9a09g077: Add GMAC nodes")
Signed-off-by: Ovidiu Panait <ovidiu.panait.rb@renesas.com>
---
 arch/arm64/boot/dts/renesas/r9a09g077.dtsi | 27 ++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/arch/arm64/boot/dts/renesas/r9a09g077.dtsi b/arch/arm64/boot/dts/renesas/r9a09g077.dtsi
index 40494159831d..bac39390ead7 100644
--- a/arch/arm64/boot/dts/renesas/r9a09g077.dtsi
+++ b/arch/arm64/boot/dts/renesas/r9a09g077.dtsi
@@ -642,36 +642,45 @@ queue7 {
 
 			mtl_tx_setup0: tx-queues-config {
 				snps,tx-queues-to-use = <8>;
+				snps,tx-sched-wrr;
 
 				queue0 {
+					snps,weight = <0x10>;
 					snps,dcb-algorithm;
 				};
 
 				queue1 {
+					snps,weight = <0x11>;
 					snps,dcb-algorithm;
 				};
 
 				queue2 {
+					snps,weight = <0x12>;
 					snps,dcb-algorithm;
 				};
 
 				queue3 {
+					snps,weight = <0x13>;
 					snps,dcb-algorithm;
 				};
 
 				queue4 {
+					snps,weight = <0x14>;
 					snps,dcb-algorithm;
 				};
 
 				queue5 {
+					snps,weight = <0x15>;
 					snps,dcb-algorithm;
 				};
 
 				queue6 {
+					snps,weight = <0x16>;
 					snps,dcb-algorithm;
 				};
 
 				queue7 {
+					snps,weight = <0x17>;
 					snps,dcb-algorithm;
 				};
 			};
@@ -788,36 +797,45 @@ queue7 {
 
 			mtl_tx_setup1: tx-queues-config {
 				snps,tx-queues-to-use = <8>;
+				snps,tx-sched-wrr;
 
 				queue0 {
+					snps,weight = <0x10>;
 					snps,dcb-algorithm;
 				};
 
 				queue1 {
+					snps,weight = <0x11>;
 					snps,dcb-algorithm;
 				};
 
 				queue2 {
+					snps,weight = <0x12>;
 					snps,dcb-algorithm;
 				};
 
 				queue3 {
+					snps,weight = <0x13>;
 					snps,dcb-algorithm;
 				};
 
 				queue4 {
+					snps,weight = <0x14>;
 					snps,dcb-algorithm;
 				};
 
 				queue5 {
+					snps,weight = <0x15>;
 					snps,dcb-algorithm;
 				};
 
 				queue6 {
+					snps,weight = <0x16>;
 					snps,dcb-algorithm;
 				};
 
 				queue7 {
+					snps,weight = <0x17>;
 					snps,dcb-algorithm;
 				};
 			};
@@ -934,36 +952,45 @@ queue7 {
 
 			mtl_tx_setup2: tx-queues-config {
 				snps,tx-queues-to-use = <8>;
+				snps,tx-sched-wrr;
 
 				queue0 {
+					snps,weight = <0x10>;
 					snps,dcb-algorithm;
 				};
 
 				queue1 {
+					snps,weight = <0x11>;
 					snps,dcb-algorithm;
 				};
 
 				queue2 {
+					snps,weight = <0x12>;
 					snps,dcb-algorithm;
 				};
 
 				queue3 {
+					snps,weight = <0x13>;
 					snps,dcb-algorithm;
 				};
 
 				queue4 {
+					snps,weight = <0x14>;
 					snps,dcb-algorithm;
 				};
 
 				queue5 {
+					snps,weight = <0x15>;
 					snps,dcb-algorithm;
 				};
 
 				queue6 {
+					snps,weight = <0x16>;
 					snps,dcb-algorithm;
 				};
 
 				queue7 {
+					snps,weight = <0x17>;
 					snps,dcb-algorithm;
 				};
 			};
-- 
2.34.1

[PATCH 5/5] arm64: dts: renesas: r9a09g078: Switch GBETH TX queue scheduling to WRR

[Ovidiu Panait]

The GBETH ethernet nodes don't specify a TX scheduling policy, so stmmac
falls back to Strict Priority. In this configuration the queue with the
highest priority gets all the traffic, starving the others under load.

Under sustained UDP TX load with multiple data streams, this starvation
triggers spurious adapter resets due to TX queue timeouts:

  iperf3 -c <ip> -i0 -t60 --bind-dev end0 -u -b0 -P4
  end0: NETDEV WATCHDOG: CPU: 1: transmit queue 1 timed out 5228 ms
  end0: Reset adapter.

Investigation shows that only the highest priority queue is advancing
while the others stall for more than 5 seconds, causing a netdev watchdog
reset.

Switch the TX scheduling policy to Weighted-Round-Robin (WRR) so that
traffic is processed across all queues, eliminating the stalls.

Fixes: c4698a34993b ("arm64: dts: renesas: r9a09g087: Add GMAC nodes")
Signed-off-by: Ovidiu Panait <ovidiu.panait.rb@renesas.com>
---
 arch/arm64/boot/dts/renesas/r9a09g087.dtsi | 27 ++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/arch/arm64/boot/dts/renesas/r9a09g087.dtsi b/arch/arm64/boot/dts/renesas/r9a09g087.dtsi
index e8d4f76949cc..03b976d93e10 100644
--- a/arch/arm64/boot/dts/renesas/r9a09g087.dtsi
+++ b/arch/arm64/boot/dts/renesas/r9a09g087.dtsi
@@ -643,36 +643,45 @@ queue7 {
 
 			mtl_tx_setup0: tx-queues-config {
 				snps,tx-queues-to-use = <8>;
+				snps,tx-sched-wrr;
 
 				queue0 {
+					snps,weight = <0x10>;
 					snps,dcb-algorithm;
 				};
 
 				queue1 {
+					snps,weight = <0x11>;
 					snps,dcb-algorithm;
 				};
 
 				queue2 {
+					snps,weight = <0x12>;
 					snps,dcb-algorithm;
 				};
 
 				queue3 {
+					snps,weight = <0x13>;
 					snps,dcb-algorithm;
 				};
 
 				queue4 {
+					snps,weight = <0x14>;
 					snps,dcb-algorithm;
 				};
 
 				queue5 {
+					snps,weight = <0x15>;
 					snps,dcb-algorithm;
 				};
 
 				queue6 {
+					snps,weight = <0x16>;
 					snps,dcb-algorithm;
 				};
 
 				queue7 {
+					snps,weight = <0x17>;
 					snps,dcb-algorithm;
 				};
 			};
@@ -790,36 +799,45 @@ queue7 {
 
 			mtl_tx_setup1: tx-queues-config {
 				snps,tx-queues-to-use = <8>;
+				snps,tx-sched-wrr;
 
 				queue0 {
+					snps,weight = <0x10>;
 					snps,dcb-algorithm;
 				};
 
 				queue1 {
+					snps,weight = <0x11>;
 					snps,dcb-algorithm;
 				};
 
 				queue2 {
+					snps,weight = <0x12>;
 					snps,dcb-algorithm;
 				};
 
 				queue3 {
+					snps,weight = <0x13>;
 					snps,dcb-algorithm;
 				};
 
 				queue4 {
+					snps,weight = <0x14>;
 					snps,dcb-algorithm;
 				};
 
 				queue5 {
+					snps,weight = <0x15>;
 					snps,dcb-algorithm;
 				};
 
 				queue6 {
+					snps,weight = <0x16>;
 					snps,dcb-algorithm;
 				};
 
 				queue7 {
+					snps,weight = <0x17>;
 					snps,dcb-algorithm;
 				};
 			};
@@ -937,36 +955,45 @@ queue7 {
 
 			mtl_tx_setup2: tx-queues-config {
 				snps,tx-queues-to-use = <8>;
+				snps,tx-sched-wrr;
 
 				queue0 {
+					snps,weight = <0x10>;
 					snps,dcb-algorithm;
 				};
 
 				queue1 {
+					snps,weight = <0x11>;
 					snps,dcb-algorithm;
 				};
 
 				queue2 {
+					snps,weight = <0x12>;
 					snps,dcb-algorithm;
 				};
 
 				queue3 {
+					snps,weight = <0x13>;
 					snps,dcb-algorithm;
 				};
 
 				queue4 {
+					snps,weight = <0x14>;
 					snps,dcb-algorithm;
 				};
 
 				queue5 {
+					snps,weight = <0x15>;
 					snps,dcb-algorithm;
 				};
 
 				queue6 {
+					snps,weight = <0x16>;
 					snps,dcb-algorithm;
 				};
 
 				queue7 {
+					snps,weight = <0x17>;
 					snps,dcb-algorithm;
 				};
 			};
-- 
2.34.1

Re: [PATCH 3/5] arm64: dts: renesas: r9a09g047: Switch GBETH TX queue scheduling to WRR

[Tommaso Merciai]

On Wed, Jul 22, 2026 at 08:53:51AM +0000, Ovidiu Panait wrote:
> The GBETH ethernet nodes don't specify a TX scheduling policy, so stmmac
> falls back to Strict Priority. In this configuration the queue with the
> highest priority gets all the traffic, starving the others under load.
> 
> Under sustained UDP TX load with multiple data streams, this starvation
> triggers spurious adapter resets due to TX queue timeouts:
> 
>   iperf3 -c <ip> -i0 -t60 --bind-dev end0 -u -b0 -P4
>   end0: NETDEV WATCHDOG: CPU: 1: transmit queue 1 timed out 5228 ms
>   end0: Reset adapter.
> 
> Investigation shows that only the highest priority queue is advancing
> while the others stall for more than 5 seconds, causing a netdev watchdog
> reset.
> 
> Switch the TX scheduling policy to Weighted-Round-Robin (WRR) so that
> traffic is processed across all queues, eliminating the stalls.
>

Tested on RZ/G3E evk:

Tested-by: Tommaso Merciai <tommaso.merciai.xr@bp.renesas.com>

Kind Regards,
Tommaso

> Fixes: 41ffbb1c42d3 ("arm64: dts: renesas: r9a09g047: Add GBETH nodes")
> Signed-off-by: Ovidiu Panait <ovidiu.panait.rb@renesas.com>
> ---
>  arch/arm64/boot/dts/renesas/r9a09g047.dtsi | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/arch/arm64/boot/dts/renesas/r9a09g047.dtsi b/arch/arm64/boot/dts/renesas/r9a09g047.dtsi
> index 73757e8e2197..060405d4a2dd 100644
> --- a/arch/arm64/boot/dts/renesas/r9a09g047.dtsi
> +++ b/arch/arm64/boot/dts/renesas/r9a09g047.dtsi
> @@ -1913,23 +1913,28 @@ queue3 {
>  
>  			mtl_tx_setup0: tx-queues-config {
>  				snps,tx-queues-to-use = <4>;
> +				snps,tx-sched-wrr;
>  
>  				queue0 {
> +					snps,weight = <0x10>;
>  					snps,dcb-algorithm;
>  					snps,priority = <0x1>;
>  				};
>  
>  				queue1 {
> +					snps,weight = <0x12>;
>  					snps,dcb-algorithm;
>  					snps,priority = <0x2>;
>  				};
>  
>  				queue2 {
> +					snps,weight = <0x14>;
>  					snps,dcb-algorithm;
>  					snps,priority = <0x4>;
>  				};
>  
>  				queue3 {
> +					snps,weight = <0x18>;
>  					snps,dcb-algorithm;
>  					snps,priority = <0x8>;
>  				};
> @@ -2013,23 +2018,28 @@ queue3 {
>  
>  			mtl_tx_setup1: tx-queues-config {
>  				snps,tx-queues-to-use = <4>;
> +				snps,tx-sched-wrr;
>  
>  				queue0 {
> +					snps,weight = <0x10>;
>  					snps,dcb-algorithm;
>  					snps,priority = <0x1>;
>  				};
>  
>  				queue1 {
> +					snps,weight = <0x12>;
>  					snps,dcb-algorithm;
>  					snps,priority = <0x2>;
>  				};
>  
>  				queue2 {
> +					snps,weight = <0x14>;
>  					snps,dcb-algorithm;
>  					snps,priority = <0x4>;
>  				};
>  
>  				queue3 {
> +					snps,weight = <0x18>;
>  					snps,dcb-algorithm;
>  					snps,priority = <0x8>;
>  				};
> -- 
> 2.34.1
> 

Re: [PATCH 1/5] arm64: dts: renesas: r9a09g057: Switch GBETH TX queue scheduling to WRR

[Geert Uytterhoeven]

On Wed, 22 Jul 2026 at 10:54, Ovidiu Panait
<ovidiu.panait.rb@renesas.com> wrote:
> The GBETH ethernet nodes don't specify a TX scheduling policy, so stmmac
> falls back to Strict Priority. In this configuration the queue with the
> highest priority gets all the traffic, starving the others under load.
>
> Under sustained UDP TX load with multiple data streams, this starvation
> triggers spurious adapter resets due to TX queue timeouts:
>
>   iperf3 -c <ip> -i0 -t60 --bind-dev end0 -u -b0 -P4
>   end0: NETDEV WATCHDOG: CPU: 1: transmit queue 1 timed out 5228 ms
>   end0: Reset adapter.
>
> Investigation shows that only the highest priority queue is advancing
> while the others stall for more than 5 seconds, causing a netdev watchdog
> reset.
>
> Switch the TX scheduling policy to Weighted-Round-Robin (WRR) so that
> traffic is processed across all queues, eliminating the stalls.
>
> Fixes: 050ee38d0002 ("arm64: dts: renesas: r9a09g057: Add GBETH nodes")
> Signed-off-by: Ovidiu Panait <ovidiu.panait.rb@renesas.com>

LGTM, so
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
i.e. will queue in renesas-devel for v7.4.

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH 5/5] arm64: dts: renesas: r9a09g078: Switch GBETH TX queue scheduling to WRR

[Geert Uytterhoeven]

Hi Ovidiu,

Thanks for your patch!

s/078/087/

On Wed, 22 Jul 2026 at 10:55, Ovidiu Panait
<ovidiu.panait.rb@renesas.com> wrote:
> The GBETH ethernet nodes don't specify a TX scheduling policy, so stmmac
> falls back to Strict Priority. In this configuration the queue with the
> highest priority gets all the traffic, starving the others under load.
>
> Under sustained UDP TX load with multiple data streams, this starvation
> triggers spurious adapter resets due to TX queue timeouts:
>
>   iperf3 -c <ip> -i0 -t60 --bind-dev end0 -u -b0 -P4
>   end0: NETDEV WATCHDOG: CPU: 1: transmit queue 1 timed out 5228 ms
>   end0: Reset adapter.
>
> Investigation shows that only the highest priority queue is advancing
> while the others stall for more than 5 seconds, causing a netdev watchdog
> reset.
>
> Switch the TX scheduling policy to Weighted-Round-Robin (WRR) so that
> traffic is processed across all queues, eliminating the stalls.
>
> Fixes: c4698a34993b ("arm64: dts: renesas: r9a09g087: Add GMAC nodes")
> Signed-off-by: Ovidiu Panait <ovidiu.panait.rb@renesas.com>

LGTM, so
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
i.e. will queue in renesas-devel for v7.4, with the SoC part number fixed.

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH 2/5] arm64: dts: renesas: r9a09g056: Switch GBETH TX queue scheduling to WRR

[Geert Uytterhoeven]

On Wed, 22 Jul 2026 at 10:54, Ovidiu Panait
<ovidiu.panait.rb@renesas.com> wrote:
> The GBETH ethernet nodes don't specify a TX scheduling policy, so stmmac
> falls back to Strict Priority. In this configuration the queue with the
> highest priority gets all the traffic, starving the others under load.
>
> Under sustained UDP TX load with multiple data streams, this starvation
> triggers spurious adapter resets due to TX queue timeouts:
>
>   iperf3 -c <ip> -i0 -t60 --bind-dev end0 -u -b0 -P4
>   end0: NETDEV WATCHDOG: CPU: 1: transmit queue 1 timed out 5228 ms
>   end0: Reset adapter.
>
> Investigation shows that only the highest priority queue is advancing
> while the others stall for more than 5 seconds, causing a netdev watchdog
> reset.
>
> Switch the TX scheduling policy to Weighted-Round-Robin (WRR) so that
> traffic is processed across all queues, eliminating the stalls.
>
> Fixes: c8c8a57c5b40 ("arm64: dts: renesas: r9a09g056: Add GBETH nodes")
> Signed-off-by: Ovidiu Panait <ovidiu.panait.rb@renesas.com>

LGTM, so
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
i.e. will queue in renesas-devel for v7.4.

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH 4/5] arm64: dts: renesas: r9a09g077: Switch GBETH TX queue scheduling to WRR

[Geert Uytterhoeven]

On Wed, 22 Jul 2026 at 10:55, Ovidiu Panait
<ovidiu.panait.rb@renesas.com> wrote:
> The GBETH ethernet nodes don't specify a TX scheduling policy, so stmmac
> falls back to Strict Priority. In this configuration the queue with the
> highest priority gets all the traffic, starving the others under load.
>
> Under sustained UDP TX load with multiple data streams, this starvation
> triggers spurious adapter resets due to TX queue timeouts:
>
>   iperf3 -c <ip> -i0 -t60 --bind-dev end0 -u -b0 -P4
>   end0: NETDEV WATCHDOG: CPU: 1: transmit queue 1 timed out 5228 ms
>   end0: Reset adapter.
>
> Investigation shows that only the highest priority queue is advancing
> while the others stall for more than 5 seconds, causing a netdev watchdog
> reset.
>
> Switch the TX scheduling policy to Weighted-Round-Robin (WRR) so that
> traffic is processed across all queues, eliminating the stalls.
>
> Fixes: 394c1e24a4cf ("arm64: dts: renesas: r9a09g077: Add GMAC nodes")
> Signed-off-by: Ovidiu Panait <ovidiu.panait.rb@renesas.com>

LGTM, so
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
i.e. will queue in renesas-devel for v7.4.

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH 3/5] arm64: dts: renesas: r9a09g047: Switch GBETH TX queue scheduling to WRR

[Geert Uytterhoeven]

On Wed, 22 Jul 2026 at 10:55, Ovidiu Panait
<ovidiu.panait.rb@renesas.com> wrote:
> The GBETH ethernet nodes don't specify a TX scheduling policy, so stmmac
> falls back to Strict Priority. In this configuration the queue with the
> highest priority gets all the traffic, starving the others under load.
>
> Under sustained UDP TX load with multiple data streams, this starvation
> triggers spurious adapter resets due to TX queue timeouts:
>
>   iperf3 -c <ip> -i0 -t60 --bind-dev end0 -u -b0 -P4
>   end0: NETDEV WATCHDOG: CPU: 1: transmit queue 1 timed out 5228 ms
>   end0: Reset adapter.
>
> Investigation shows that only the highest priority queue is advancing
> while the others stall for more than 5 seconds, causing a netdev watchdog
> reset.
>
> Switch the TX scheduling policy to Weighted-Round-Robin (WRR) so that
> traffic is processed across all queues, eliminating the stalls.
>
> Fixes: 41ffbb1c42d3 ("arm64: dts: renesas: r9a09g047: Add GBETH nodes")
> Signed-off-by: Ovidiu Panait <ovidiu.panait.rb@renesas.com>

LGTM, so
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
i.e. will queue in renesas-devel for v7.4.

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds