Enabling Spinning

Onload User Guide (UG1586)

Document ID

UG1586

Release Date

2023-07-31

Revision

1.2 English

To enable spinning in Onload:

Set EF_POLL_USEC. This causes Onload to spin on the processor for up to the specified number of microseconds before blocking. This setting is used in TCP and UDP and also in recv(), select(), pselect() and poll(), ppoll() and epoll_wait(), epoll_pwait() and onload_ordered_epoll_wait(). Use the following command:

export EF_POLL_USEC=100000

Note: If neither of the spinning options EF_POLL_USEC and EF_SPIN_USEC are set, Onload will resort to default interrupt driven behavior because the EF_INT_DRIVEN environment variable is enabled by default.

Setting the EF_POLL_USEC variable also sets the following environment variables.

EF_SPIN_USEC=EF_POLL_USEC
EF_SELECT_SPIN=1
EF_EPOLL_SPIN=1
EF_POLL_SPIN=1
EF_PKT_WAIT_SPIN=1
EF_TCP_SEND_SPIN=1
EF_UDP_RECV_SPIN=1
EF_UDP_SEND_SPIN=1
EF_TCP_RECV_SPIN=1
EF_BUZZ_USEC=MIN(EF_POLL_USEC, 100)
EF_SOCK_LOCK_BUZZ=1
EF_STACK_LOCK_BUZZ=1

Turn off adaptive moderation and set interrupt moderation to a high value (microseconds) to avoid flooding the system with interrupts. Use the following command:

/sbin/ethtool -C eth2 rx-usecs 60 adaptive-rx off

See Meta Options for more details.