On Tue, Jun 18, 2019 at 5:51 AM Björn Töpel <bjorn.topel@xxxxxxxxx> wrote:
>
> On Sat, 15 Jun 2019 at 01:25, William Tu <u9012063@xxxxxxxxx> wrote:
> >
> > Hi,
> >
> > In my implementation[1], I'm doing s.t like
> > tx_done = xsk_ring_cons__peek(&xsk->umem->cq, BATCH_SIZE, &idx_cq);
> > if (tx_done > 0) {
> > xsk_ring_cons__release(&xsk->umem->cq, tx_done);
> > xsk->outstanding_tx -= tx_done;
> > }
> >
> > I expect if tx_done returns 32, then after calling xsk_ring_cons__release,
> > the next time I call xsk_ring_cons__peek, I should get idx_cq + 32.
> > However, sometimes I see the same value of idx_cq is returned as previous, even
> > when tx_done > 0. Is this the expected behavior?
> >
> > I experiment with xdpsock_user.c with the patch below and run
> > ~/bpf-next/samples/bpf# ./xdpsock -l -N -z -i eth3
> > using bpf-next commit 5e2ac390fbd08b2a462db66cef2663e4db0d5191
> >
>
> Will, apologies for the slow response.
>
> Hmm, it looks like a bug. We'll take a look!
>
No worries, thanks for the update!
Or let me know if I can try something to get more info.
the xsk_ring_cons__peek just keeps doing
*idx = cons->cached_cons;
cons->cached_cons += entries;
It's weird to see idx value not advancing 'entries' occasionally.
Regards,
William
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