X4 SHRUB Controller Now Interrupt Driven - X4 SHRUB Controller Now Interrupt Driven - UG1586

Onload User Guide (UG1586)

Document ID
UG1586
Release Date
2026-06-08
Revision
1.5 English

The SHRUB Controller for managing shared access to X4 Express datapath queues no longer spins when interrupts are enabled, instead waiting for interesting events to occur before doing any work. This enables multiple SHRUB controllers to run on the same core. Users should be aware that clients freeing buffers do not generate interrupts.

As before, you can enable interrupts by providing the -i flag at SHRUB controller creation time. For Onload, the EF_SHRUB_USE_INTERRUPTS environment variable configures this if a SHRUB controller is not manually created. An additional -p option has been added to the SHRUB controller, which allows the specification of a time after which a poll must occur even if no interrupts have been seen. No corresponding option exists yet in Onload to configure this.