Re: [PATCH 5/5] selftests: net: add rss_multiqueue test variant to iou-zcrx

[David Wei <dw@davidwei.uk>]

On 2026-04-08 09:38, Juanlu Herrero wrote:
> Add multi-port support to the iou-zcrx test binary and a new
> rss_multiqueue Python test variant that exercises multi-queue zero-copy
> receive with per-port flow rule steering.
> 
> In multi-port mode, the server creates N listening sockets on
> consecutive ports (cfg_port, cfg_port+1, ...) and uses epoll to accept
> one connection per socket. Each client thread connects to its
> corresponding port. Per-port ntuple flow rules steer traffic to
> different NIC hardware queues, each with its own zcrx instance.
> 
> For single-thread mode (the default), behavior is unchanged: one socket
> on cfg_port, one thread, one queue.
> 
> Signed-off-by: Juanlu Herrero <juanlu@fastmail.com>
> ---
>   .../selftests/drivers/net/hw/iou-zcrx.c       | 81 ++++++++++++++-----
>   .../selftests/drivers/net/hw/iou-zcrx.py      | 45 ++++++++++-
>   2 files changed, 104 insertions(+), 22 deletions(-)
> 
> diff --git a/tools/testing/selftests/drivers/net/hw/iou-zcrx.c b/tools/testing/selftests/drivers/net/hw/iou-zcrx.c
> index 646682167bb0..1f33d7127185 100644
> --- a/tools/testing/selftests/drivers/net/hw/iou-zcrx.c
> +++ b/tools/testing/selftests/drivers/net/hw/iou-zcrx.c

Please make all changes in iou-zcrx.c in a single patch. Then patch 5
only changes the Python selftest.

[...]
> @@ -397,12 +410,36 @@ static void run_server(void)
>   	if (cfg_dry_run)
>   		goto join;
>   
> +	epfd = epoll_create1(0);
> +	if (epfd < 0)
> +		error(1, 0, "epoll_create1()");
> +
>   	for (i = 0; i < cfg_num_threads; i++) {
> -		ctxs[i].connfd = accept(fd, NULL, NULL);
> -		if (ctxs[i].connfd < 0)
> -			error(1, 0, "accept()");
> +		ev.events = EPOLLIN;
> +		ev.data.u32 = i;
> +		if (epoll_ctl(epfd, EPOLL_CTL_ADD, fds[i], &ev) < 0)
> +			error(1, 0, "epoll_ctl()");
>   	}
>   
> +	accepted = 0;
> +	while (accepted < cfg_num_threads) {

You're using epoll here but it is still accepting a fixed nr of
connections. The server should be able to accept an arbitrary nr of
connections, dispatching them to the server worker threads.

Also with multiple queues, connections must be dispatched according to
their NAPI IDs to the correct server workers.

> +		nfds = epoll_wait(epfd, events, 64, 5000);
> +		if (nfds < 0)
> +			error(1, 0, "epoll_wait()");
> +		if (nfds == 0)
> +			error(1, 0, "epoll_wait() timeout");
> +
> +		for (i = 0; i < nfds; i++) {
> +			int idx = events[i].data.u32;
> +
> +			ctxs[idx].connfd = accept(fds[idx], NULL, NULL);
> +			if (ctxs[idx].connfd < 0)
> +				error(1, 0, "accept()");
> +			accepted++;
> +		}
> +	}
> +
> +	close(epfd);
>   	pthread_barrier_wait(&barrier);
>   
>   join: