RE: How to rte_epoll_wait for IPC?

["Morten Brørup" <mb@smartsharesystems.com>]

> From: Stephen Hemminger [mailto:stephen@networkplumber.org]
> Sent: Friday, 6 October 2023 18.03
> 
> On Fri, 6 Oct 2023 12:03:46 +0200
> Morten Brørup <mb@smartsharesystems.com> wrote:
> 
> > 2. The "processing" thread receives its packets from the rte_ring.
> This thread should sleep until packets are ready for it in the rte_ring.
> >
> > The "ingress" thread knows when it puts packets into the rte_ring, so
> it can signal that event to the "processing" thread, to wake it up;
> either as an interrupt/signal, or through a file descriptor. Is this
> supported by rte_epoll (or other DPDK APIs), and how?
> 
> When having to do this in applications, I used a eventfd() as well as
> the rte ring.
> The ingress write's to eventfd and the other thread used epoll on the
> fd.
> 
> Optimized this by having the ingress thread only signal via write if
> ring was in empty state.
> And the reader thread only needs to do (epoll/read) if ring became empty
> during last cycle;
> i.e num packets from rte_ring_burst() was 0.
> 
> Basically, when using epoll and other SW event models, you need to turn
> all data sources
> into file descriptors.

This sounds exactly like what I am looking for.

Are there DPDK APIs for eventfd(), so I can use them with rte_epoll_wait?