EF_UL_EPOLL

Onload User Guide (UG1586)

Document ID
UG1586
Release Date
2023-07-31
Revision
1.2 English
Name
ul_epoll
Default
1
Minimum
0
Maximum
3
Scope
per-process

Choose epoll implementation. The choices are:

  • 0 - kernel (unaccelerated)
  • 1 - user-level (accelerated, lowest latency)
  • 2 - kernel-accelerated (best when there are lots of sockets in the set and mode 3 is not suitable)
  • 3 - user-level (accelerated, lowest latency, scalable, supports socket caching).

The default is the user-level implementation (1).

Mode 3 can offer benefits over mode 1, particularly with larger sets. However, this mode has some restrictions:

  • It does not support epoll sets that exist across fork().
  • It does not support monitoring the readiness of the set's epoll fd via a another epoll/poll/select.