How to Tune the Linux Kernel for Networking

WHAT TO EXPECT

In this article, users will learn how to tweak the Linux kernel for increased packet rates, minimizing packet trops.

PLEASE NOTE

Kernel Tuning should be the last option when setting up and configuring the Linux xNIC for performance. We expect users to validate network loss BEFORE attempting to optimize/tune the network kernel.

These settings have been found to increase packet rates and minimize packet drops. These settings are for implementing on a Linux machine running the swxtch-xNIC service.

To do this:

Open the /etc/sysctl.conf to begin editing.
Add the following lines:
```
net.core.rmem_default=26214400
net.core.rmem_max=26214400
```
PLEASE NOTE
The suggested kernel parameters above only optimize the receive buffer. If you need to increase the size of the send buffer, please contact support@swxtch.io.

Once the desired changes have been added to /etc/sysctl.conf, save changes and exit.

Run the following command to validate the change:

sudo sysctl -p

Example:

$ sudo sysctl -p
net.core.rmem_default = 26214400
net.core.rmem_max = 26214400

Run the following command to validate the rmem max.

sudo sysctl net.core.rmem_max

Example:

$ sudo sysctl net.core.rmem_max
net.core.rmem_max = 26214400

If the values are the expected ones, the kernel has been tweaked, and now users should do a test to validate transfers.