On Tue, 5 May 2020 at 16:28, Maxim Mikityanskiy <maximmi@xxxxxxxxxxxx> wrote:
>
[...]
> >
> > - if (((d->addr + d->len) & q->chunk_mask) != (d->addr & q->chunk_mask) ||
> > - d->options) {
> > +static inline bool xskq_cons_is_valid_desc(struct xsk_queue *q,
> > + struct xdp_desc *d,
> > + struct xdp_umem *umem)
> > +{
> > + if (!xp_validate_desc(umem->pool, d)) {
>
> I did some performance debugging and came to conclusion that this
> function call is the culprit of the TX speed degradation that I
> experience. I still don't know if it's the only reason or not, but I
> clearly see a degradation when xskq_cons_is_valid_desc is not fully
> inlined, but calls a function. E.g., I've put the code that handles the
> aligned mode into a separate function in a different file, and it caused
> the similar speed decrease.
>
Thanks for looking in to, and finding this!
I'll make sure the xp_validate_desc() call is inlined for the next
revision.
A note to myself: I need to check the performance for an LLVM build
with LTO enabled.
Cheers,
Björn
