[dpdk-dev] [PATCH v2] doc: add preferred burst size support
Bruce Richardson
bruce.richardson at intel.com
Thu Feb 1 14:27:25 CET 2018
On Thu, Feb 01, 2018 at 06:18:23PM +0530, Shreyansh Jain wrote:
> rte_eth_rx_burst(..,nb_pkts) function has semantic that if return value
> is smaller than requested, application can consider it end of packet
> stream. Some hardware can only support smaller burst sizes which need
> to be advertised. Similar is the case for Tx burst.
>
> This patch adds deprecation notice for rte_eth_dev_info structure as
> two new members, for preferred Rx and Tx burst size would be added -
> impacting the size of the structure.
>
> Signed-off-by: Shreyansh Jain <shreyansh.jain at nxp.com>
> ---
> * Refer: http://dpdk.org/dev/patchwork/patch/32112 for context
>
> v2:
> - fix spelling error in deprecation notice
>
> doc/guides/rel_notes/deprecation.rst | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/doc/guides/rel_notes/deprecation.rst b/doc/guides/rel_notes/deprecation.rst
> index d59ad5988..fdc7656fa 100644
> --- a/doc/guides/rel_notes/deprecation.rst
> +++ b/doc/guides/rel_notes/deprecation.rst
> @@ -59,3 +59,11 @@ Deprecation Notices
> be added between the producer and consumer structures. The size of the
> structure and the offset of the fields will remain the same on
> platforms with 64B cache line, but will change on other platforms.
> +
> +* ethdev: Currently, if the rte_eth_rx_burst() function returns a value less
> + than *nb_pkts*, the application will assume that no more packets are present.
> + Some of the hw queue based hardware can only support smaller burst for RX
> + and TX and thus break the expectation of the rx_burst API. Similar is the
> + case for TX burst. ``rte_eth_dev_info`` will be added with two new
> + parameters, ``uint16_t pref_rx_burst`` and ``uint16_t pref_tx_burst``,
> + for preferred RX and TX burst sizes, respectively.
> --
> 2.14.1
>
LTGM as far as it goes, but following discussion on this patch,
http://dpdk.org/ml/archives/dev/2018-January/089585.html
I think we might also want to add in parameters for "pref_tx_ring_sz"
and "pref_rx_ring_sz" too. While it is the case that, once the structure
is changed, we can make multiple additional changes, I think it might be
worth mentioning as many as we can for completeness.
Another point to consider, is whether we might want to add in a
sub-structure for "preferred_settings" to hold all these, rather than
just adding them as new fields. It might help with making names more
readable (though also longer).
struct {
uint16_t rx_burst;
uint16_t tx_burst;
uint16_t rx_ring_sz;
uint16_t tx_ring_sz;
} preferred_settings;
In any case, for this or subsequent versions:
Acked-by: Bruce Richardson <bruce.richardson at intel.com>
/Bruce
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