>
> Acked-by: Ethan Jackson <et...@nicira.com>
>
> One question I had for a future patch. Have you considered prefetching
> more packets at once? I.E. 4 at a time or something?
> That's how these things are typically written, though I don't know if it would
> actually affect things.
yeah, I was going to suggest the same thing. In most DPDK apps, we would
prefetch about 3.
>
> Merged.
> Ethan
>
> On Mon, Jun 15, 2015 at 11:06 AM, Daniele Di Proietto
> <diproiet...@vmware.com> wrote:
> > It appears that miniflow_extract() in emc_processing() spends a lot of
> > cycles waiting for the packet's data to be read.
> >
> > Prefetching the next packet's data while parsing removes this delay.
> > For a single flow pipeline the throughput improves by ~10%. With a
> > more realistic pipeline the change has a much smaller effect (~0.5%
> > improvement)
> >
> > Signed-off-by: Daniele Di Proietto <diproiet...@vmware.com>
> > ---
> > lib/dpif-netdev.c | 5 +++++
> > 1 file changed, 5 insertions(+)
> >
> > diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c index
> > 5b82c8b..f13169c 100644
> > --- a/lib/dpif-netdev.c
> > +++ b/lib/dpif-netdev.c
> > @@ -3150,6 +3150,11 @@ emc_processing(struct dp_netdev_pmd_thread
> *pmd, struct dp_packet **packets,
> > continue;
> > }
> >
> > + if (i != cnt - 1) {
> > + /* Prefetch next packet data */
> > + OVS_PREFETCH(dp_packet_data(packets[i+1]));
> > + }
> > +
> > miniflow_extract(packets[i], &key.mf);
> > key.len = 0; /* Not computed yet. */
> > key.hash = dpif_netdev_packet_get_rss_hash(packets[i],
> > &key.mf);
> > --
> > 2.1.4
> >
> > _______________________________________________
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> > dev@openvswitch.org
> > http://openvswitch.org/mailman/listinfo/dev
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