Re: [dpdk-dev] [PATCH v12] ethdev: new Rx/Tx offloads API

["Dai, Wei" <wei.dai@intel.com>]

Hi, Thomas & Ferruh
Thanks for your feedback.
I agree with your comments and I am working on the latest commit of the repo dpdk-next-net.
I will submit a new patch to adopt your suggestion.
Please wait for a while ...


> -----Original Message-----
> From: Thomas Monjalon [mailto:thomas@monjalon.net]
> Sent: Monday, May 14, 2018 4:37 PM
> To: Dai, Wei <wei.dai@intel.com>
> Cc: dev@dpdk.org; Yigit, Ferruh <ferruh.yigit@intel.com>; Zhang, Qi Z
> <qi.z.zhang@intel.com>
> Subject: Re: [dpdk-dev] [PATCH v12] ethdev: new Rx/Tx offloads API
> 
> Wei Dai,
> Do you agree with my comments?
> Could we have a wording patch to squash in RC3?
> 
> 
> 10/05/2018 23:39, Thomas Monjalon:
> > Hi,
> >
> > A first general comment: a lot of spaces are still inside parens.
> > You can grep '( )'.
> >
> > 10/05/2018 13:56, Wei Dai:
> > > --- a/doc/guides/prog_guide/poll_mode_drv.rst
> > > +++ b/doc/guides/prog_guide/poll_mode_drv.rst
> > > +A per-queue offloading can be enabled on a queue and disabled on
> another queue at the same time.
> > > +A pure per-port offload is the one supported by device but not
> per-queue type.
> >
> > Another way to say it: pure per-port offloads are not directly
> > advertised but are the port offloads capabilities minus the queue
> capabilities.
> > port capabilities = pure per-port capabilities + queue capabilities
> >
> > > +A pure per-port offloading can't be enabled on a queue and disabled on
> another queue at the same time.
> > > +A pure per-port offloading must be enabled or disabled on all queues at
> the same time.
> > > +Any offloading is per-queue or pure per-port type, but can't be both
> types at same devices.
> > > +A per-port offloading can be enabled or disabled on all queues at the
> same time.
> >
> > This sentence is useless: it says any offload can be setup for the whole
> port.
> >
> > > +It is certain that both per-queue and pure per-port offloading are
> per-port type.
> >
> > This sentence is confusing. I cannot understand it.
> >
> >
> > >  The different offloads capabilities can be queried using
> ``rte_eth_dev_info_get()``.
> > > +The dev_info->[rt]x_queue_offload_capa returned from
> ``rte_eth_dev_info_get()`` includes all per-queue offloading capabilities.
> > > +The dev_info->[rt]x_offload_capa returned from
> ``rte_eth_dev_info_get()`` includes all per-port and per-queue offloading
> capabilities.
> >
> > If you want to stick with pure per-port wording, you should say
> > [rt]x_offload_capa is the port capabilities (including pure per-port and
> per-queue).
> >
> >
> > > --- a/lib/librte_ethdev/rte_ethdev.c
> > > +++ b/lib/librte_ethdev/rte_ethdev.c
> > > +	/* Any requested offloading must be within its device capabilities
> */
> > > +	if ((local_conf.rxmode.offloads & dev_info.rx_offload_capa) !=
> > > +	     local_conf.rxmode.offloads) {
> > > +		ethdev_log(ERR, "ethdev port_id=%d requested Rx offloads "
> > > +				"0x%" PRIx64 " doesn't match Rx offloads "
> > > +				"capabilities 0x%" PRIx64 " in %s( )\n",
> > > +				port_id,
> > > +				local_conf.rxmode.offloads,
> > > +				dev_info.rx_offload_capa,
> > > +				__func__);
> >
> > We could have a comment saying that an error will be returned in next
> version.
> >
> > > +	}
> > > +	if ((local_conf.txmode.offloads & dev_info.tx_offload_capa) !=
> > > +	     local_conf.txmode.offloads) {
> > > +		ethdev_log(ERR, "ethdev port_id=%d requested Tx offloads "
> > > +				"0x%" PRIx64 " doesn't match Tx offloads "
> > > +				"capabilities 0x%" PRIx64 " in %s( )\n",
> > > +				port_id,
> > > +				local_conf.txmode.offloads,
> > > +				dev_info.tx_offload_capa,
> > > +				__func__);
> >
> > idem
> >
> > > +	}
> >
> >
> > > +	/*
> > > +	 * If an offloading has already been enabled in
> > > +	 * rte_eth_dev_configure(), it has been enabled on all queues,
> > > +	 * so there is no need to enable it in this queue again.
> > > +	 * The local_conf.offloads input to underlying PMD only carries
> > > +	 * those offloadings which are only enabled on this queue and
> > > +	 * not enabled on all queues.
> > > +	 * The underlying PMD must be aware of this point.
> >
> > I think the last sentence is useless.
> >
> > > +	 */
> > > +	local_conf.offloads &= ~dev->data->dev_conf.rxmode.offloads;
> > > +
> > > +	/*
> > > +	 * New added offloadings for this queue are those not enabled in
> > > +	 * rte_eth_dev_configure( ) and they must be per-queue type.
> > > +	 * A pure per-port offloading can't be enabled on a queue while
> > > +	 * disabled on another queue. A pure per-port offloading can't
> > > +	 * be enabled for any queue as new added one if it hasn't been
> > > +	 * enabled in rte_eth_dev_configure( ).
> > > +	 */
> > > +	if ((local_conf.offloads & dev_info.rx_queue_offload_capa) !=
> > > +	     local_conf.offloads) {
> > > +		ethdev_log(ERR, "Ethdev port_id=%d rx_queue_id=%d, new "
> > > +				"added offloads 0x%" PRIx64 " must be "
> > > +				"within pre-queue offload capabilities 0x%"
> > > +				PRIx64 " in %s( )\n",
> > > +				port_id,
> > > +				rx_queue_id,
> > > +				local_conf.offloads,
> > > +				dev_info.rx_queue_offload_capa,
> > > +				__func__);
> >
> > idem, we can have a comment about error in next version
> >
> > > +	}
> >
> >
> > > --- a/lib/librte_ethdev/rte_ethdev.h
> > > +++ b/lib/librte_ethdev/rte_ethdev.h
> > >  	uint64_t rx_offload_capa;
> > > -	/**< Device per port RX offload capabilities. */
> > > +	/**< All RX offload capabilities including all per queue ones */
> >
> > OK
> > per queue -> per-queue
> >
> > >  	uint64_t tx_offload_capa;
> > > -	/**< Device per port TX offload capabilities. */
> > > +	/**< All TX offload capabilities.including all per-queue ones */
> >
> > Typo: there is a dot instead of space.
> >
> > >  	uint64_t rx_queue_offload_capa;
> > >  	/**< Device per queue RX offload capabilities. */
> >
> > Here you should add more comments:
> > 	No need to repeat flags already enabled at port level.
> > 	A flag enabled at port level, cannot be disabled at queue level.
> >
> >
> > > + *     -  Any offloading set in eth_conf->[rt]xmode.offloads must be
> within
> > > + *        the [rt]x_offload_capa returned from
> rte_eth_dev_infos_get().
> >
> > OK
> >
> > > + *        Any type of device supported offloading set in the input
> argument
> > > + *        eth_conf->[rt]xmode.offloads to rte_eth_dev_configure() is
> enabled
> > > + *        on all [RT]x queues and it can't be disabled no matter
> whether
> > > + *        it is cleared or set in the input argument
> [rt]x_conf->offloads
> > > + *        to rte_eth_[rt]x_queue_setup().
> >
> > last part can be simpler: cannot be disabled in queue setup.
> > "[RT]x queues" can be simply "queues".
> >
> >
> > > + *   If an offloading set in rx_conf->offloads
> > > + *   hasn't been set in the input argument eth_conf->rxmode.offloads
> > > + *   to rte_eth_dev_configure(), it is a new added offloading, it must
> be
> > > + *   per-queue type and it is enabled for the queue.
> >
> > OK
> > Another wording:
> > The offloads not advertised in queue capabilities, and not already
> > enabled at port level, are rejected.
> 
> 
>