RE: epoll_wait() performance

From: David Laight
Date: Thu Nov 28 2019 - 05:17:40 EST


From: Eric Dumazet
> Sent: 27 November 2019 17:47
...
> A QUIC server handles hundred of thousands of ' UDP flows' all using only one UDP socket
> per cpu.
>
> This is really the only way to scale, and does not need kernel changes to efficiently
> organize millions of UDP sockets (huge memory footprint even if we get right how
> we manage them)
>
> Given that UDP has no state, there is really no point trying to have one UDP
> socket per flow, and having to deal with epoll()/poll() overhead.

How can you do that when all the UDP flows have different destination port numbers?
These are message flows not idempotent requests.
I don't really want to collect the packets before they've been processed by IP.

I could write a driver that uses kernel udp sockets to generate a single message queue
than can be efficiently processed from userspace - but it is a faff compiling it for
the systems kernel version.

David

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