Pre-Test Configuration - UG1586

The following configuration options are used to decrease latency.

First, set some configuration options that decrease latency for Onload acceleration technologies. On both machines:

1. Stop the irqbalance service on the server:

   systemctl stop irqbalance

2. Allocate huge pages. For example, to configure 1024 huge pages:

   # sysctl -w vm.nr_hugepages=1024

   To make this change persistent, update /etc/sysctl.conf. For example:

   # echo "vm.nr_hugepages = 1024" >> /etc/sysctl.conf

   For more information refer to Allocating Huge Pages.

3. Consider the selection of the NUMA node, as this affects latency on a NUMA-aware system. Refer to Onload Deployment on NUMA Systems.

Now perform the following configuration to improve latency without Onload.

1. Set tuned to use the cpu-partitioning profile. This makes it easy to isolate cores that can be dedicated to interrupt handling or to an application. For example, to isolate cores 1-3:

   # echo "isolated_cores=1-3" \
        > /etc/tuned/cpu-partitioning-variables.conf
   # tuned-adm profile cpu-partitioning

2. Enable the kernel “busy poll” feature to disable interrupts and allow polling of the socket receive queue. The following values are recommended:

   # sysctl net.core.busy_poll=50 && sysctl net.core.busy_read=50