Re: [dpdk-dev] [PATCH v2] net/ice: add flow mark hint support

["Zhang, Qi Z" <qi.z.zhang@intel.com>]

> -----Original Message-----
> From: Stillwell Jr, Paul M <paul.m.stillwell.jr@intel.com>
> Sent: Saturday, November 16, 2019 12:37 AM
> To: Zhang, Qi Z <qi.z.zhang@intel.com>; Ye, Xiaolong <xiaolong.ye@intel.com>
> Cc: dev@dpdk.org; Zhang, Qi Z <qi.z.zhang@intel.com>
> Subject: RE: [dpdk-dev] [PATCH v2] net/ice: add flow mark hint support
> 
> 
> > -----Original Message-----
> > From: dev <dev-bounces@dpdk.org> On Behalf Of Qi Zhang
> > Sent: Thursday, November 14, 2019 7:42 PM
> > To: Ye, Xiaolong <xiaolong.ye@intel.com>
> > Cc: dev@dpdk.org; Zhang, Qi Z <qi.z.zhang@intel.com>
> > Subject: [dpdk-dev] [PATCH v2] net/ice: add flow mark hint support
> >
> > Since not all data paths support flow mark, the driver need a hint
> > from application to select the correct data path if flow mark is
> > required. The patch introduce a devarg "flow-mark-support" as a
> > workaround solution, since a standard way is still ongoing.
> >
> 
> I understand the need for this, but this seems problematic. Once a customer
> starts using this, then it has to be in the code forever because they are going to
> expect it to work forever. Maybe this should be marked with something that
> indicates it is temporary? Something like the experimental tagging that is done
> in other parts of the code?

Yes, since this is a workaround solution, claim it as an experimental looks like a good idea.
But I didn't see there is any documented standard way to claim a devarg as experimental.
Not sure if that should be part of the ABI policy or already some effort to standardize devargs is on the way.

Anyway as you can see, I have below statement in ice.rst to claim this is a workaround solution, 

	This hint should be removed when any of below condition ready.
	1) all data path support flow mark (currently vPMD does not)
	2) a new offload like RTE_DEV_RX_OFFLOAD_FLOW_MARK be introduced as a standard way to hint. 

And I can add words "This is experimental" to emphasized it.
 
Regards
Qi
> 
> > Signed-off-by: Qi Zhang <qi.z.zhang@intel.com>
> > ---
> >
> > v2:
> > - fix typo
> >
> >  doc/guides/nics/ice.rst               | 10 ++++++++++
> >  drivers/net/ice/ice_ethdev.c          | 11 ++++++++++-
> >  drivers/net/ice/ice_ethdev.h          |  1 +
> >  drivers/net/ice/ice_rxtx_vec_common.h |  5 +++++
> >  4 files changed, 26 insertions(+), 1 deletion(-)
> >
> > diff --git a/doc/guides/nics/ice.rst b/doc/guides/nics/ice.rst index
> > 1a426438d..f7016d338 100644
> > --- a/doc/guides/nics/ice.rst
> > +++ b/doc/guides/nics/ice.rst
> > @@ -80,6 +80,16 @@ Runtime Config Options
> >
> >      -w 80:00.0,pipeline-mode-support=1
> >
> > +- ``Flow Mark Support`` (default ``0``)
> > +
> > +  This is a hint to the driver to select the data path that support
> > + flow mark extraction  by default. This hint should be removed when
> > + any of
> > below condition ready.
> > +  1) all data path support flow mark (currently vPMD does not)
> > +  2) a new offload like RTE_DEV_RX_OFFLOAD_FLOW_MARK be introduced
> > as a standard way to hint.
> > +  Example::
> > +
> > +    -w 80:00.0,flow-mark-support=1
> > +
> >  - ``Protocol extraction for per queue``
> >
> >    Configure the RX queues to do protocol extraction into mbuf for
> > protocol diff --git a/drivers/net/ice/ice_ethdev.c
> > b/drivers/net/ice/ice_ethdev.c index abf00d404..9f2cb2f40 100644
> > --- a/drivers/net/ice/ice_ethdev.c
> > +++ b/drivers/net/ice/ice_ethdev.c
> > @@ -23,11 +23,13 @@
> >  /* devargs */
> >  #define ICE_SAFE_MODE_SUPPORT_ARG "safe-mode-support"
> >  #define ICE_PIPELINE_MODE_SUPPORT_ARG  "pipeline-mode-support"
> > +#define ICE_FLOW_MARK_SUPPORT_ARG"flow-mark-support"
> >  #define ICE_PROTO_XTR_ARG         "proto_xtr"
> >
> >  static const char * const ice_valid_args[] = {
> > ICE_SAFE_MODE_SUPPORT_ARG,  ICE_PIPELINE_MODE_SUPPORT_ARG,
> > +ICE_FLOW_MARK_SUPPORT_ARG,
> >  ICE_PROTO_XTR_ARG,
> >  NULL
> >  };
> > @@ -1987,6 +1989,12 @@ static int ice_parse_devargs(struct rte_eth_dev
> > *dev)
> >
> >  ret = rte_kvargs_process(kvlist,
> > ICE_PIPELINE_MODE_SUPPORT_ARG,
> >   &parse_bool, &ad-
> > >devargs.pipe_mode_support);
> > +if (ret)
> > +goto bail;
> > +
> > +ret = rte_kvargs_process(kvlist, ICE_FLOW_MARK_SUPPORT_ARG,
> > +&parse_bool, &ad-
> > >devargs.flow_mark_support);
> > +printf("flow_mark = %d\n", ad->devargs.flow_mark_support);
> >
> >  bail:
> >  rte_kvargs_free(kvlist);
> > @@ -4571,7 +4579,8 @@ RTE_PMD_REGISTER_KMOD_DEP(net_ice, "*
> igb_uio |
> > uio_pci_generic | vfio-pci"); RTE_PMD_REGISTER_PARAM_STRING(net_ice,
> >        ICE_PROTO_XTR_ARG
> > "=[queue:]<vlan|ipv4|ipv6|ipv6_flow|tcp>"
> >        ICE_SAFE_MODE_SUPPORT_ARG "=<0|1>"
> > -      ICE_PIPELINE_MODE_SUPPORT_ARG "=<0|1>");
> > +      ICE_PIPELINE_MODE_SUPPORT_ARG "=<0|1>"
> > +      ICE_FLOW_MARK_SUPPORT_ARG "=<0|1>");
> >
> >  RTE_INIT(ice_init_log)
> >  {
> > diff --git a/drivers/net/ice/ice_ethdev.h
> > b/drivers/net/ice/ice_ethdev.h index 4a0d37b32..4d35339a7 100644
> > --- a/drivers/net/ice/ice_ethdev.h
> > +++ b/drivers/net/ice/ice_ethdev.h
> > @@ -391,6 +391,7 @@ struct ice_devargs {  int safe_mode_support;
> > uint8_t proto_xtr_dflt;  int pipe_mode_support;
> > +int flow_mark_support;
> >  uint8_t proto_xtr[ICE_MAX_QUEUE_NUM];  };
> >
> > diff --git a/drivers/net/ice/ice_rxtx_vec_common.h
> > b/drivers/net/ice/ice_rxtx_vec_common.h
> > index 080ca4175..086428898 100644
> > --- a/drivers/net/ice/ice_rxtx_vec_common.h
> > +++ b/drivers/net/ice/ice_rxtx_vec_common.h
> > @@ -268,6 +268,11 @@ ice_rx_vec_dev_check_default(struct rte_eth_dev
> > *dev)  {
> >  int i;
> >  struct ice_rx_queue *rxq;
> > +struct ice_adapter *ad =
> > +ICE_DEV_PRIVATE_TO_ADAPTER(dev->data->dev_private);
> > +
> > +if (ad->devargs.flow_mark_support)
> > +return -1;
> >
> >  for (i = 0; i < dev->data->nb_rx_queues; i++) {  rxq =
> > dev->data->rx_queues[i];
> > --
> > 2.13.6
>