Re: [dpdk-dev] [PATCH v4] Add toeplitz hash algorithm used by RSS

[Vladimir Medvedkin <medvedkinv@gmail.com>]

Hi Bruce,

2015-06-19 18:59 GMT+03:00 Richardson, Bruce <bruce.richardson@intel.com>:

>
>
> > -----Original Message-----
> > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Vladimir Medvedkin
> > Sent: Friday, June 19, 2015 3:56 PM
> > To: dev@dpdk.org
> > Subject: [dpdk-dev] [PATCH v4] Add toeplitz hash algorithm used by RSS
> >
> > v4 changes
> > - Fix copyright
> > - rename bswap_mask constant, add rte_ prefix
> > - change rte_ipv[46]_tuple struct
> > - change rte_thash_load_v6_addr prototype
> >
> > v3 changes
> > - Rework API to be more generic
> > - Add sctp_tag into tuple
> >
> > v2 changes
> > - Add ipv6 support
> > - Various style fixes
> >
>
> Missing signoff line.
>
> > ---
> >  lib/librte_hash/Makefile    |   1 +
> >  lib/librte_hash/rte_thash.h | 202
> > ++++++++++++++++++++++++++++++++++++++++++++
> >  2 files changed, 203 insertions(+)
> >  create mode 100644 lib/librte_hash/rte_thash.h
> >
> <...snip...>
> > +
> > +/* Byte swap mask used for converting IPv6 address 4-byte chunks to CPU
> > byte order */
> > +static const __m128i rte_thash_ipv6_bswap_mask = {0x0405060700010203,
> > 0x0C0D0E0F08090A0B};
> > +
> > +#define RTE_THASH_V4_L3       2      /*calculate hash of ipv4 header
> only*/
> > +#define RTE_THASH_V4_L4       3      /*calculate hash of ipv4 +
> transport
> > headers*/
> > +#define RTE_THASH_V6_L3       8      /*calculate hash of ipv6 header
> only
> > */
> > +#define RTE_THASH_V6_L4       9      /*calculate hash of ipv6 +
> transport
> > headers */
>
> I'm still not seeing why these values need to be defined here, rather than
> in a specific app.
> Also, the choice of values for these defines seems strange to me? How were
> they chosen?
>
This is a predefined values. They mean the length (in 4-bytes) of the
input data
in hashing. I think it's like defines in rte_ip.h, for example.

>
> /Bruce
>
>