[v4] doc: announce API change in ethdev offload flags

  From: Pavan Nikhilesh <pbhagavatula@marvell.com>

Add new offload flags ``DEV_RX_OFFLOAD_RSS`` and ``DEV_RX_OFFLOAD_FLOW_MARK``.
Add new function ``rte_eth_dev_set_supported_ptypes`` to allow application to
set specific ptypes to be updated in ``rte_mbuf::packet_type``

Signed-off-by: Pavan Nikhilesh <pbhagavatula@marvell.com>
Acked-by: Andrew Rybchenko <arybchenko@solarflare.com>
Acked-by: Jerin Jacob <jerinj@marvell.com>
Acked-by: Hemant Agrawal <hemant.agrawal@nxp.com>
---
 doc/guides/rel_notes/deprecation.rst | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

--
2.17.1
  

Hi 

> 
> From: Pavan Nikhilesh <pbhagavatula@marvell.com>
> 
> Add new offload flags ``DEV_RX_OFFLOAD_RSS`` and ``DEV_RX_OFFLOAD_FLOW_MARK``.
> Add new function ``rte_eth_dev_set_supported_ptypes`` to allow application to
> set specific ptypes to be updated in ``rte_mbuf::packet_type``
> 
> Signed-off-by: Pavan Nikhilesh <pbhagavatula@marvell.com>
> Acked-by: Andrew Rybchenko <arybchenko@solarflare.com>
> Acked-by: Jerin Jacob <jerinj@marvell.com>
> Acked-by: Hemant Agrawal <hemant.agrawal@nxp.com>
> ---
>  doc/guides/rel_notes/deprecation.rst | 23 +++++++++++++++++++++++
>  1 file changed, 23 insertions(+)
> 
> diff --git a/doc/guides/rel_notes/deprecation.rst b/doc/guides/rel_notes/deprecation.rst
> index 37b8592b6..e4e2a85d7 100644
> --- a/doc/guides/rel_notes/deprecation.rst
> +++ b/doc/guides/rel_notes/deprecation.rst
> @@ -78,3 +78,26 @@ Deprecation Notices
>    to set new power environment if power environment was already initialized.
>    In this case the function will return -1 unless the environment is unset first
>    (using ``rte_power_unset_env``). Other function usage scenarios will not change.
> +
> +* ethdev: New offload flags ``DEV_RX_OFFLOAD_RSS_HASH`` and ``DEV_RX_OFFLOAD_FLOW_MARK``
> +  will be added in 19.11.
> +  This will allow application to enable or disable PMDs from updating
> +  ``rte_mbuf::hash::rss`` and ``rte_mbuf::hash::fdir`` respectively.
> +  This scheme will allow PMDs to avoid writes to ``rte_mbuf`` fields on Rx and
> +  thereby improve Rx performance if application wishes do so.
> +  In 19.11 PMDs will still update the fields even when the offloads are not
> +  enabled.
> +
> +* ethdev: New function ``rte_eth_dev_set_supported_ptypes`` will be added in
> +  19.11.

As I said in my previous mail, I do support the idea, though few nits below.

> +  This will allow application to request PMD to set specific ptypes defined
> +  through ``rte_eth_dev_set_supported_ptypes`` in ``rte_mbuf::packet_type``.
> +  If application doesn't want any ptype information it can call
> +  ``rte_eth_dev_set_supported_ptypes(ethdev_id, RTE_PTYPE_UNKNOWN)``

Probably worth to mention that in that case packet_type will be set to 0
(PMD still need to set the value).

> +  If application doesn't call ``rte_eth_dev_set_supported_ptypes`` PMD can
> +  return ``rte_mbuf::packet_type`` with ``rte_eth_dev_get_supported_ptypes``.
> +  If application is interested only in L2/L3 layer, it can inform the PMD to update
> + ``rte_mbuf::packet_type`` with L2/L3 ptype by calling
> + ``rte_eth_dev_set_supported_ptypes(ethdev_id, RTE_PTYPE_L2_MASK | RTE_PTYPE_L3_MASK)``.
> +  This scheme will allow PMDs to avoid writes to ``rte_mbuf`` fields on Rx and

As I understand, PMD will still need to write ptype value.
Though it will help PMD to avoid figuring out ptype values, when user don't need that information.

> +  thereby improve Rx performance if application wishes do so.
> --
> 2.17.1
  

Hi,

>-----Original Message-----
>From: Ananyev, Konstantin <konstantin.ananyev@intel.com>
>Sent: Friday, August 9, 2019 2:17 PM
>To: Pavan Nikhilesh Bhagavatula <pbhagavatula@marvell.com>; Jerin
>Jacob Kollanukkaran <jerinj@marvell.com>;
>stephen@networkplumber.org; arybchenko@solarflare.com;
>hemant.agrawal@nxp.com; thomas@monjalon.net; Yigit, Ferruh
><ferruh.yigit@intel.com>; Richardson, Bruce
><bruce.richardson@intel.com>; Neil Horman
><nhorman@tuxdriver.com>; Mcnamara, John
><john.mcnamara@intel.com>; Kovacevic, Marko
><marko.kovacevic@intel.com>
>Cc: dev@dpdk.org
>Subject: RE: [dpdk-dev] [patch v4] doc: announce API change in
>ethdev offload flags
>Hi
>
>>
>> From: Pavan Nikhilesh <pbhagavatula@marvell.com>
>>
>> Add new offload flags ``DEV_RX_OFFLOAD_RSS`` and
>``DEV_RX_OFFLOAD_FLOW_MARK``.
>> Add new function ``rte_eth_dev_set_supported_ptypes`` to allow
>application to
>> set specific ptypes to be updated in ``rte_mbuf::packet_type``
>>
>> Signed-off-by: Pavan Nikhilesh <pbhagavatula@marvell.com>
>> Acked-by: Andrew Rybchenko <arybchenko@solarflare.com>
>> Acked-by: Jerin Jacob <jerinj@marvell.com>
>> Acked-by: Hemant Agrawal <hemant.agrawal@nxp.com>
>> ---
>>  doc/guides/rel_notes/deprecation.rst | 23
>+++++++++++++++++++++++
>>  1 file changed, 23 insertions(+)
>>
>> diff --git a/doc/guides/rel_notes/deprecation.rst
>b/doc/guides/rel_notes/deprecation.rst
>> index 37b8592b6..e4e2a85d7 100644
>> --- a/doc/guides/rel_notes/deprecation.rst
>> +++ b/doc/guides/rel_notes/deprecation.rst
>> @@ -78,3 +78,26 @@ Deprecation Notices
>>    to set new power environment if power environment was already
>initialized.
>>    In this case the function will return -1 unless the environment is
>unset first
>>    (using ``rte_power_unset_env``). Other function usage scenarios
>will not change.
>> +
>> +* ethdev: New offload flags ``DEV_RX_OFFLOAD_RSS_HASH`` and
>``DEV_RX_OFFLOAD_FLOW_MARK``
>> +  will be added in 19.11.
>> +  This will allow application to enable or disable PMDs from updating
>> +  ``rte_mbuf::hash::rss`` and ``rte_mbuf::hash::fdir`` respectively.
>> +  This scheme will allow PMDs to avoid writes to ``rte_mbuf`` fields
>on Rx and
>> +  thereby improve Rx performance if application wishes do so.
>> +  In 19.11 PMDs will still update the fields even when the offloads are
>not
>> +  enabled.
>> +
>> +* ethdev: New function ``rte_eth_dev_set_supported_ptypes`` will
>be added in
>> +  19.11.
>
>As I said in my previous mail, I do support the idea, though few nits
>below.
>
>> +  This will allow application to request PMD to set specific ptypes
>defined
>> +  through ``rte_eth_dev_set_supported_ptypes`` in
>``rte_mbuf::packet_type``.
>> +  If application doesn't want any ptype information it can call
>> +  ``rte_eth_dev_set_supported_ptypes(ethdev_id,
>RTE_PTYPE_UNKNOWN)``
>
>Probably worth to mention that in that case packet_type will be set to 0
>(PMD still need to set the value).

Ack, will update in v5.

>
>> +  If application doesn't call ``rte_eth_dev_set_supported_ptypes``
>PMD can
>> +  return ``rte_mbuf::packet_type`` with
>``rte_eth_dev_get_supported_ptypes``.
>> +  If application is interested only in L2/L3 layer, it can inform the PMD
>to update
>> + ``rte_mbuf::packet_type`` with L2/L3 ptype by calling
>> + ``rte_eth_dev_set_supported_ptypes(ethdev_id,
>RTE_PTYPE_L2_MASK | RTE_PTYPE_L3_MASK)``.
>> +  This scheme will allow PMDs to avoid writes to ``rte_mbuf`` fields
>on Rx and
>
>As I understand, PMD will still need to write ptype value.
>Though it will help PMD to avoid figuring out ptype values, when user
>don't need that information.

I will reword to ``will allow PMDs to avoid lookup to internal ptype table``.

>
>> +  thereby improve Rx performance if application wishes do so.
>> --
>> 2.17.1

Thanks,
Pavan.
  

I think the silent breaking is still not solved for 
DEV_RX_OFFLOAD_RSS_HASH and DEV_RX_OFFLOAD_FLOW_MARK.

An old application will still compile without any problem, but the RSS 
hash will not be written and the app will break... They should be 
negative. Eg DEV_RX_OFFLOAD_NO_RSS_HASH and DEV_RX_OFFLOAD_NO_FLOW_MARK?

Then, regarding the idea, are we sure it's better to add a configuration 
check/a branch than always copying a few bytes from a warm cache line to 
a warm cache line? Or some HW could free some internal resources? But 
drivers are free to ignore it so it is not a problem as opposed to 
silent breaking.

Tom

On 2019-08-09 10:17, pbhagavatula@marvell.com wrote:
> From: Pavan Nikhilesh <pbhagavatula@marvell.com>
> 
> Add new offload flags ``DEV_RX_OFFLOAD_RSS`` and ``DEV_RX_OFFLOAD_FLOW_MARK``.
> Add new function ``rte_eth_dev_set_supported_ptypes`` to allow application to
> set specific ptypes to be updated in ``rte_mbuf::packet_type``
> 
> Signed-off-by: Pavan Nikhilesh <pbhagavatula@marvell.com>
> Acked-by: Andrew Rybchenko <arybchenko@solarflare.com>
> Acked-by: Jerin Jacob <jerinj@marvell.com>
> Acked-by: Hemant Agrawal <hemant.agrawal@nxp.com>
> ---
>   doc/guides/rel_notes/deprecation.rst | 23 +++++++++++++++++++++++
>   1 file changed, 23 insertions(+)
> 
> diff --git a/doc/guides/rel_notes/deprecation.rst b/doc/guides/rel_notes/deprecation.rst
> index 37b8592b6..e4e2a85d7 100644
> --- a/doc/guides/rel_notes/deprecation.rst
> +++ b/doc/guides/rel_notes/deprecation.rst
> @@ -78,3 +78,26 @@ Deprecation Notices
>     to set new power environment if power environment was already initialized.
>     In this case the function will return -1 unless the environment is unset first
>     (using ``rte_power_unset_env``). Other function usage scenarios will not change.
> +
> +* ethdev: New offload flags ``DEV_RX_OFFLOAD_RSS_HASH`` and ``DEV_RX_OFFLOAD_FLOW_MARK``
> +  will be added in 19.11.
> +  This will allow application to enable or disable PMDs from updating
> +  ``rte_mbuf::hash::rss`` and ``rte_mbuf::hash::fdir`` respectively.
> +  This scheme will allow PMDs to avoid writes to ``rte_mbuf`` fields on Rx and
> +  thereby improve Rx performance if application wishes do so.
> +  In 19.11 PMDs will still update the fields even when the offloads are not
> +  enabled.
> +
> +* ethdev: New function ``rte_eth_dev_set_supported_ptypes`` will be added in
> +  19.11.
> +  This will allow application to request PMD to set specific ptypes defined
> +  through ``rte_eth_dev_set_supported_ptypes`` in ``rte_mbuf::packet_type``.
> +  If application doesn't want any ptype information it can call
> +  ``rte_eth_dev_set_supported_ptypes(ethdev_id, RTE_PTYPE_UNKNOWN)``
> +  If application doesn't call ``rte_eth_dev_set_supported_ptypes`` PMD can
> +  return ``rte_mbuf::packet_type`` with ``rte_eth_dev_get_supported_ptypes``.
> +  If application is interested only in L2/L3 layer, it can inform the PMD to update
> + ``rte_mbuf::packet_type`` with L2/L3 ptype by calling
> + ``rte_eth_dev_set_supported_ptypes(ethdev_id, RTE_PTYPE_L2_MASK | RTE_PTYPE_L3_MASK)``.
> +  This scheme will allow PMDs to avoid writes to ``rte_mbuf`` fields on Rx and
> +  thereby improve Rx performance if application wishes do so.
> --
> 2.17.1
>
  

On 8/9/19 12:13 PM, Tom Barbette wrote:
> I think the silent breaking is still not solved for 
> DEV_RX_OFFLOAD_RSS_HASH and DEV_RX_OFFLOAD_FLOW_MARK.
>
> An old application will still compile without any problem, but the RSS 
> hash will not be written and the app will break... They should be 
> negative. Eg DEV_RX_OFFLOAD_NO_RSS_HASH and DEV_RX_OFFLOAD_NO_FLOW_MARK?
>
> Then, regarding the idea, are we sure it's better to add a 
> configuration check/a branch than always copying a few bytes from a 
> warm cache line to a warm cache line? Or some HW could free some 
> internal resources? But drivers are free to ignore it so it is not a 
> problem as opposed to silent breaking.

It could be not delivered from NIC to host saving PCIe bandwidth. E.g. 
flow mark plus RSS hash is 8 byte and it is more than 10% for small packet.

> Tom
>
> On 2019-08-09 10:17, pbhagavatula@marvell.com wrote:
>> From: Pavan Nikhilesh <pbhagavatula@marvell.com>
>>
>> Add new offload flags ``DEV_RX_OFFLOAD_RSS`` and 
>> ``DEV_RX_OFFLOAD_FLOW_MARK``.
>> Add new function ``rte_eth_dev_set_supported_ptypes`` to allow 
>> application to
>> set specific ptypes to be updated in ``rte_mbuf::packet_type``
>>
>> Signed-off-by: Pavan Nikhilesh <pbhagavatula@marvell.com>
>> Acked-by: Andrew Rybchenko <arybchenko@solarflare.com>
>> Acked-by: Jerin Jacob <jerinj@marvell.com>
>> Acked-by: Hemant Agrawal <hemant.agrawal@nxp.com>
>> ---
>>   doc/guides/rel_notes/deprecation.rst | 23 +++++++++++++++++++++++
>>   1 file changed, 23 insertions(+)
>>
>> diff --git a/doc/guides/rel_notes/deprecation.rst 
>> b/doc/guides/rel_notes/deprecation.rst
>> index 37b8592b6..e4e2a85d7 100644
>> --- a/doc/guides/rel_notes/deprecation.rst
>> +++ b/doc/guides/rel_notes/deprecation.rst
>> @@ -78,3 +78,26 @@ Deprecation Notices
>>     to set new power environment if power environment was already 
>> initialized.
>>     In this case the function will return -1 unless the environment 
>> is unset first
>>     (using ``rte_power_unset_env``). Other function usage scenarios 
>> will not change.
>> +
>> +* ethdev: New offload flags ``DEV_RX_OFFLOAD_RSS_HASH`` and 
>> ``DEV_RX_OFFLOAD_FLOW_MARK``
>> +  will be added in 19.11.
>> +  This will allow application to enable or disable PMDs from updating
>> +  ``rte_mbuf::hash::rss`` and ``rte_mbuf::hash::fdir`` respectively.
>> +  This scheme will allow PMDs to avoid writes to ``rte_mbuf`` fields 
>> on Rx and
>> +  thereby improve Rx performance if application wishes do so.
>> +  In 19.11 PMDs will still update the fields even when the offloads 
>> are not
>> +  enabled.
>> +
>> +* ethdev: New function ``rte_eth_dev_set_supported_ptypes`` will be 
>> added in
>> +  19.11.
>> +  This will allow application to request PMD to set specific ptypes 
>> defined
>> +  through ``rte_eth_dev_set_supported_ptypes`` in 
>> ``rte_mbuf::packet_type``.
>> +  If application doesn't want any ptype information it can call
>> +  ``rte_eth_dev_set_supported_ptypes(ethdev_id, RTE_PTYPE_UNKNOWN)``
>> +  If application doesn't call ``rte_eth_dev_set_supported_ptypes`` 
>> PMD can
>> +  return ``rte_mbuf::packet_type`` with 
>> ``rte_eth_dev_get_supported_ptypes``.
>> +  If application is interested only in L2/L3 layer, it can inform 
>> the PMD to update
>> + ``rte_mbuf::packet_type`` with L2/L3 ptype by calling
>> + ``rte_eth_dev_set_supported_ptypes(ethdev_id, RTE_PTYPE_L2_MASK | 
>> RTE_PTYPE_L3_MASK)``.
>> +  This scheme will allow PMDs to avoid writes to ``rte_mbuf`` fields 
>> on Rx and
>> +  thereby improve Rx performance if application wishes do so.
>> -- 
>> 2.17.1
>>
  

> -----Original Message-----
> From: Tom Barbette <barbette@kth.se>
> Sent: Friday, August 9, 2019 2:44 PM
> To: Pavan Nikhilesh Bhagavatula <pbhagavatula@marvell.com>; Jerin Jacob
> Kollanukkaran <jerinj@marvell.com>; stephen@networkplumber.org;
> arybchenko@solarflare.com; hemant.agrawal@nxp.com;
> thomas@monjalon.net; ferruh.yigit@intel.com;
> bruce.richardson@intel.com; Neil Horman <nhorman@tuxdriver.com>; John
> McNamara <john.mcnamara@intel.com>; Marko Kovacevic
> <marko.kovacevic@intel.com>
> Cc: dev@dpdk.org
> Subject: Re: [dpdk-dev] [patch v4] doc: announce API change in ethdev
> offload flags
> 
> I think the silent breaking is still not solved for DEV_RX_OFFLOAD_RSS_HASH
> and DEV_RX_OFFLOAD_FLOW_MARK.

Unlike ptype, presence of  rss hash and flow_mark will be marked in ol_flags
as PKT_RX_RSS_HASH  and PKT_RX_FDIR_ID. So NO application contract breakage.

> 
> An old application will still compile without any problem, but the RSS hash will
> not be written and the app will break... They should be negative. Eg
> DEV_RX_OFFLOAD_NO_RSS_HASH and
> DEV_RX_OFFLOAD_NO_FLOW_MARK?
> 
> Then, regarding the idea, are we sure it's better to add a configuration
> check/a branch than always copying a few bytes from a warm cache line to a
> warm cache line? Or some HW could free some internal resources? But
> drivers are free to ignore it so it is not a problem as opposed to silent
> breaking.
> 
> Tom
> 
> On 2019-08-09 10:17, pbhagavatula@marvell.com wrote:
> > From: Pavan Nikhilesh <pbhagavatula@marvell.com>
> >
> > Add new offload flags ``DEV_RX_OFFLOAD_RSS`` and
> ``DEV_RX_OFFLOAD_FLOW_MARK``.
> > Add new function ``rte_eth_dev_set_supported_ptypes`` to allow
> application to
> > set specific ptypes to be updated in ``rte_mbuf::packet_type``
> >
> > Signed-off-by: Pavan Nikhilesh <pbhagavatula@marvell.com>
> > Acked-by: Andrew Rybchenko <arybchenko@solarflare.com>
> > Acked-by: Jerin Jacob <jerinj@marvell.com>
> > Acked-by: Hemant Agrawal <hemant.agrawal@nxp.com>
> > ---
> >   doc/guides/rel_notes/deprecation.rst | 23 +++++++++++++++++++++++
> >   1 file changed, 23 insertions(+)
> >
> > diff --git a/doc/guides/rel_notes/deprecation.rst
> b/doc/guides/rel_notes/deprecation.rst
> > index 37b8592b6..e4e2a85d7 100644
> > --- a/doc/guides/rel_notes/deprecation.rst
> > +++ b/doc/guides/rel_notes/deprecation.rst
> > @@ -78,3 +78,26 @@ Deprecation Notices
> >     to set new power environment if power environment was already
> initialized.
> >     In this case the function will return -1 unless the environment is unset
> first
> >     (using ``rte_power_unset_env``). Other function usage scenarios will not
> change.
> > +
> > +* ethdev: New offload flags ``DEV_RX_OFFLOAD_RSS_HASH`` and
> ``DEV_RX_OFFLOAD_FLOW_MARK``
> > +  will be added in 19.11.
> > +  This will allow application to enable or disable PMDs from updating
> > +  ``rte_mbuf::hash::rss`` and ``rte_mbuf::hash::fdir`` respectively.
> > +  This scheme will allow PMDs to avoid writes to ``rte_mbuf`` fields on Rx
> and
> > +  thereby improve Rx performance if application wishes do so.
> > +  In 19.11 PMDs will still update the fields even when the offloads are not
> > +  enabled.
> > +
> > +* ethdev: New function ``rte_eth_dev_set_supported_ptypes`` will be
> added in
> > +  19.11.
> > +  This will allow application to request PMD to set specific ptypes defined
> > +  through ``rte_eth_dev_set_supported_ptypes`` in
> ``rte_mbuf::packet_type``.
> > +  If application doesn't want any ptype information it can call
> > +  ``rte_eth_dev_set_supported_ptypes(ethdev_id,
> RTE_PTYPE_UNKNOWN)``
> > +  If application doesn't call ``rte_eth_dev_set_supported_ptypes`` PMD
> can
> > +  return ``rte_mbuf::packet_type`` with
> ``rte_eth_dev_get_supported_ptypes``.
> > +  If application is interested only in L2/L3 layer, it can inform the PMD to
> update
> > + ``rte_mbuf::packet_type`` with L2/L3 ptype by calling
> > + ``rte_eth_dev_set_supported_ptypes(ethdev_id, RTE_PTYPE_L2_MASK
> | RTE_PTYPE_L3_MASK)``.
> > +  This scheme will allow PMDs to avoid writes to ``rte_mbuf`` fields on Rx
> and
> > +  thereby improve Rx performance if application wishes do so.
> > --
> > 2.17.1
> >