Configuring Scalable Filters

Onload User Guide (UG1586)

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1.2 English

To enable scalable filters on a specific interface:


Various modes can be specified that can combine both passive and active open connections, optionally with RSS. For example:


For full details, see EF_SCALABLE_FILTERS.

Per interface, the MAC filter can only be installed by a single Onload stack. A cluster (see Application Clustering) might have multiple stacks and each stack could install a MAC filter on a different interface.

Sockets must be bound to the IP address of the interface.

This feature is targeted at TCP listening sockets only and connections accepted from a listening socket will share the MAC filter.

See also the following configuration parameters:

  • EF_SCALABLE_FILTERS_ENABLE turns the scalable filter feature on or off on a stack. It is not normally required, because it defaults to 1 when it is unset but EF_SCALABLE_FILTERS is set.

    The value 2, available from Onload 201805, Indicates a special mode to address a master-worker hierarchy of some event driven applications, such as NGINX.

    For full details, see EF_SCALABLE_FILTERS_ENABLE.

  • EF_SCALABLE_LISTEN_MODE, available from Onload 201805, sets the behavior of scalable listening sockets.
    • The default mode 0 accelerates connections to a local address configured on the scalable interface. Passive connections that come via other interfaces are not accelerated.
    • The non-default mode 1 rejects connections that are not to a local address configured on the scalable interface. This avoids kernel scalability issues with large numbers of listen sockets.

    For full details, see EF_SCALABLE_LISTEN_MODE.