On 4/23/2024 2:37 PM, Bagas Sanjaya wrote:
On Mon, Apr 22, 2024 at 01:39:11PM -0700, Tony Nguyen wrote:
+ The default 9-layer tree topology was deemed best for most workloads,
+ as it gives an optimal ratio of performance to configurability. However,
+ for some specific cases, this 9-layer topology might not be desired.
+ One example would be sending traffic to queues that are not a multiple
+ of 8. Because the maximum radix is limited to 8 in 9-layer topology,
+ the 9th queue has a different parent than the rest, and it's given
+ more bandwidth credits. This causes a problem when the system is
+ sending traffic to 9 queues:
+
+ | tx_queue_0_packets: 24163396
+ | tx_queue_1_packets: 24164623
+ | tx_queue_2_packets: 24163188
+ | tx_queue_3_packets: 24163701
+ | tx_queue_4_packets: 24163683
+ | tx_queue_5_packets: 24164668
+ | tx_queue_6_packets: 23327200
+ | tx_queue_7_packets: 24163853
+ | tx_queue_8_packets: 91101417 < Too much traffic is sent from 9th
+
<snipped>...
+ To verify that value has been set:
+ $ devlink dev param show pci/0000:16:00.0 name tx_scheduling_layers
For consistency with other code blocks, format above as such:
---- >8 ----
diff --git a/Documentation/networking/devlink/ice.rst b/Documentation/networking/devlink/ice.rst
index 830c04354222f8..0039ca45782400 100644
--- a/Documentation/networking/devlink/ice.rst
+++ b/Documentation/networking/devlink/ice.rst
@@ -41,15 +41,17 @@ Parameters
more bandwidth credits. This causes a problem when the system is
sending traffic to 9 queues:
- | tx_queue_0_packets: 24163396
- | tx_queue_1_packets: 24164623
- | tx_queue_2_packets: 24163188
- | tx_queue_3_packets: 24163701
- | tx_queue_4_packets: 24163683
- | tx_queue_5_packets: 24164668
- | tx_queue_6_packets: 23327200
- | tx_queue_7_packets: 24163853
- | tx_queue_8_packets: 91101417 < Too much traffic is sent from 9th
+ .. code-block:: shell
+
+ tx_queue_0_packets: 24163396
+ tx_queue_1_packets: 24164623
+ tx_queue_2_packets: 24163188
+ tx_queue_3_packets: 24163701
+ tx_queue_4_packets: 24163683
+ tx_queue_5_packets: 24164668
+ tx_queue_6_packets: 23327200
+ tx_queue_7_packets: 24163853
+ tx_queue_8_packets: 91101417 < Too much traffic is sent from 9th
To address this need, you can switch to a 5-layer topology, which
changes the maximum topology radix to 512. With this enhancement,
@@ -67,7 +69,10 @@ Parameters
You must do PCI slot powercycle for the selected topology to take effect.
To verify that value has been set:
- $ devlink dev param show pci/0000:16:00.0 name tx_scheduling_layers
+
+ .. code-block:: shell
+
+ $ devlink dev param show pci/0000:16:00.0 name tx_scheduling_layers
Info versions
=============
Thanks.
Thank You for reporting that. I will verify this issue soon.
