Re: [dpdk-dev] [PATCH 5/6] net/ena: rework RSS configuration

[Vladimir Medvedkin <medvedkinv@gmail.com>]

Hi Michal,

вт, 13 июл. 2021 г. в 18:42, Michal Krawczyk <mk@semihalf.com>:

> Allow user to specify his own hash key and hash ctrl if the
> device is supporting that. HW interprets the key in reverse byte order,
> so the PMD reorders the key before passing it to the ena_com layer.
>
> Default key is being set in random matter each time the device is being
> initialized.
>
> Moreover, make minor adjustments for reta size setting in terms
> of returning error values.
>
> RSS code was moved to ena_rss.c file to improve readability.
>
> Signed-off-by: Michal Krawczyk <mk@semihalf.com>
> Reviewed-by: Shai Brandes <shaibran@amazon.com>
> Reviewed-by: Shay Agroskin <shayagr@amazon.com>
> Reviewed-by: Amit Bernstein <amitbern@amazon.com>
> ---
>  doc/guides/nics/features/ena.ini       |   1 +
>  doc/guides/rel_notes/release_21_08.rst |   1 +
>  drivers/net/ena/ena_ethdev.c           | 230 ++--------
>  drivers/net/ena/ena_ethdev.h           |  34 ++
>  drivers/net/ena/ena_rss.c              | 592 +++++++++++++++++++++++++
>  drivers/net/ena/meson.build            |   1 +
>  6 files changed, 664 insertions(+), 195 deletions(-)
>  create mode 100644 drivers/net/ena/ena_rss.c
>

<snip>

+
> +/* ENA HW interprets the RSS key in reverse order and as in a big endian
> + * notation (uint32_t values instead of bytes). Because of that, the key
> must be
> + * processed upon interaction with ena_com layer.
> + */
> +static void ena_reorder_rss_hash_key(uint8_t *reordered_key,
> +                                   uint8_t *key,
> +                                   size_t key_size)
> +{
> +       size_t i, rev_i;
> +
> +       for (i = 0, rev_i = key_size - 1; i < key_size; ++i, --rev_i)
> +               reordered_key[i] = key[rev_i];
> +}
> +
>
>
If I understand the description correctly, you need to byteswap every
4-byte chunk of the key, but instead here it swaps all ENA_HASH_KEY_SIZE
bytes (i.e. key[0] = key[39] and so on). Consider doing something like
rte_convert_rss_key() from hash/rte_thash.h.


-- 
> 2.25.1
>
>

-- 
Regards,
Vladimir