On Wed, Feb 08, 2023 at 07:08:15PM +0200, Vladimir Oltean wrote: > Hi Maciej, > > On Wed, Feb 08, 2023 at 05:37:35PM +0100, Maciej Fijalkowski wrote: > > On Mon, Feb 06, 2023 at 12:08:37PM +0200, Vladimir Oltean wrote: > > > > Hey Vladimir, > > > > > Schedule NAPI by hand from enetc_xsk_wakeup(), and send frames from the > > > XSK TX queue from NAPI context. Add them to the completion queue from > > > the enetc_clean_tx_ring() procedure which is common for all kinds of > > > traffic. > > > > > > We reuse one of the TX rings for XDP (XDP_TX/XDP_REDIRECT) for XSK as > > > well. They are already cropped from the TX rings that the network stack > > > can use when XDP is enabled (with or without AF_XDP). > > > > > > As for XDP_REDIRECT calling enetc's ndo_xdp_xmit, I'm not sure if that > > > can run simultaneously with enetc_poll() (on different CPUs, but towards > > > the same TXQ). I guess it probably can, but idk what to do about it. > > > The problem is that enetc_xdp_xmit() sends to > > > priv->xdp_tx_ring[smp_processor_id()], while enetc_xsk_xmit() and XDP_TX > > > send to priv->xdp_tx_ring[NAPI instance]. So when the NAPI instance runs > > > > Why not use cpu id on the latter then? > > Hmm, because I want the sendto() syscall to trigger wakeup of the NAPI > that sends traffic to the proper queue_id, rather than to the queue_id > affine to the CPU that the sendto() syscall was made? Ok i was referring to the thing that using cpu id on both sides would address concurrency. Regarding your need, what i did for ice was that i assign xdp_ring to the rx_ring and within ndo_xsk_wakeup() i pick the rx_ring based on queue_id that comes as an arg: https://lore.kernel.org/bpf/20220822163257.2382487-3-anthony.l.nguyen@xxxxxxxxx/
