[PATCH] doc: refine iavf limitation or known issues

[PATCH] doc: refine iavf limitation or known issues

[Qi Zhang]

Move all VF related limitationi or known issues from i40e.rst to
intel_vf.rst, as i40evf has been removed from i40e, i40e.rst should only
cover PF's information.

The patch also fix couple typos and refine the words to be more accurate.

Signed-off-by: Qi Zhang <qi.z.zhang@intel.com>
---
 doc/guides/nics/i40e.rst     | 50 ------------------------------------
 doc/guides/nics/intel_vf.rst | 50 ++++++++++++++++++++++++++++++++++++
 2 files changed, 50 insertions(+), 50 deletions(-)

diff --git a/doc/guides/nics/i40e.rst b/doc/guides/nics/i40e.rst
index 4875774346..a0992dbc6c 100644
--- a/doc/guides/nics/i40e.rst
+++ b/doc/guides/nics/i40e.rst
@@ -638,24 +638,6 @@ used to classify MPLS packet by using a command in testpmd like:
    testpmd> flow create 0 ingress pattern eth type is 0x8847 / end \
             actions queue index <M> / end
 
-16 Byte RX Descriptor setting on DPDK VF
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-Currently the VF's RX descriptor mode is decided by PF. There's no PF-VF
-interface for VF to request the RX descriptor mode, also no interface to notify
-VF its own RX descriptor mode.
-For all available versions of the i40e driver, these drivers don't support 16
-byte RX descriptor. If the Linux i40e kernel driver is used as host driver,
-while DPDK i40e PMD is used as the VF driver, DPDK cannot choose 16 byte receive
-descriptor. The reason is that the RX descriptor is already set to 32 byte by
-the i40e kernel driver.
-In the future, if the Linux i40e driver supports 16 byte RX descriptor, user
-should make sure the DPDK VF uses the same RX descriptor mode, 16 byte or 32
-byte, as the PF driver.
-
-The same rule for DPDK PF + DPDK VF. The PF and VF should use the same RX
-descriptor mode. Or the VF RX will not work.
-
 Receive packets with Ethertype 0x88A8
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
@@ -699,38 +681,6 @@ effect.
 It's suggested to set the strict priority mode for a TC that is latency
 sensitive but no consuming much bandwidth.
 
-VF performance is impacted by PCI extended tag setting
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-To reach maximum NIC performance in the VF the PCI extended tag must be
-enabled. The DPDK i40e PF driver will set this feature during initialization,
-but the kernel PF driver does not. So when running traffic on a VF which is
-managed by the kernel PF driver, a significant NIC performance downgrade has
-been observed (for 64 byte packets, there is about 25% line-rate downgrade for
-a 25GbE device and about 35% for a 40GbE device).
-
-For kernel version >= 4.11, the kernel's PCI driver will enable the extended
-tag if it detects that the device supports it. So by default, this is not an
-issue. For kernels <= 4.11 or when the PCI extended tag is disabled it can be
-enabled using the steps below.
-
-#. Get the current value of the PCI configure register::
-
-      setpci -s <XX:XX.X> a8.w
-
-#. Set bit 8::
-
-      value = value | 0x100
-
-#. Set the PCI configure register with new value::
-
-      setpci -s <XX:XX.X> a8.w=<value>
-
-Vlan strip of VF
-~~~~~~~~~~~~~~~~
-
-The VF vlan strip function is only supported in the i40e kernel driver >= 2.1.26.
-
 DCB function
 ~~~~~~~~~~~~
 
diff --git a/doc/guides/nics/intel_vf.rst b/doc/guides/nics/intel_vf.rst
index 6498135655..09e1eb7685 100644
--- a/doc/guides/nics/intel_vf.rst
+++ b/doc/guides/nics/intel_vf.rst
@@ -647,3 +647,53 @@ Inline IPsec Support
     supports inline IPsec processing for IAVF PMD. For more details see the
     IPsec Security Gateway Sample Application and Security library
     documentation.
+
+
+Limitations or Knowing issues
+-----------------------------
+
+16 Byte RX Descriptor setting is not available
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Currently the VF's RX descriptor size is decided by PF. There's no PF-VF
+interface for VF to request the RX descriptor size, also no interface to notify
+VF its own RX descriptor size.
+For all available versions of the kernel PF drivers, these drivers don't
+support 16 bytes RX descriptor. If the Linux kernel driver is used as host driver,
+while DPDK iavf PMD is used as the VF driver, DPDK cannot choose 16 bytes receive
+descriptor. The reason is that the RX descriptor is already set to 32 bytes by
+the all existing kernel driver.
+In the future, if the any kernel driver supports 16 bytes RX descriptor, user
+should make sure the DPDK VF uses the same RX descriptor size.
+
+i40e: VF performance is impacted by PCI extended tag setting
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+To reach maximum NIC performance in the VF the PCI extended tag must be
+enabled. But the kernel driver does not set this feature during initialization.
+So when running traffic on a VF which is managed by the kernel PF driver, a
+significant NIC performance downgrade has been observed (for 64 byte packets,
+there is about 25% line-rate downgrade for a 25GbE device and about 35% for a
+40GbE device).
+
+For kernel version >= 4.11, the kernel's PCI driver will enable the extended
+tag if it detects that the device supports it. So by default, this is not an
+issue. For kernels <= 4.11 or when the PCI extended tag is disabled it can be
+enabled using the steps below.
+
+#. Get the current value of the PCI configure register::
+
+      setpci -s <XX:XX.X> a8.w
+
+#. Set bit 8::
+
+      value = value | 0x100
+
+#. Set the PCI configure register with new value::
+
+      setpci -s <XX:XX.X> a8.w=<value>
+
+i40e: Vlan strip of VF
+~~~~~~~~~~~~~~~~~~~~~~
+
+The VF vlan strip function is only supported in the i40e kernel driver >= 2.1.26.
-- 
2.31.1

RE: [PATCH] doc: refine iavf limitation or known issues

[Xing, Beilei]

> -----Original Message-----
> From: Zhang, Qi Z <qi.z.zhang@intel.com>
> Sent: Tuesday, September 6, 2022 8:42 PM
> To: Xing, Beilei <beilei.xing@intel.com>; Wu, Jingjing <jingjing.wu@intel.com>
> Cc: Yang, Qiming <qiming.yang@intel.com>; dev@dpdk.org; Zhang, Qi Z
> <qi.z.zhang@intel.com>
> Subject: [PATCH] doc: refine iavf limitation or known issues
> 
> Move all VF related limitationi or known issues from i40e.rst to intel_vf.rst,
> as i40evf has been removed from i40e, i40e.rst should only cover PF's
> information.
> 
> The patch also fix couple typos and refine the words to be more accurate.
> 
> Signed-off-by: Qi Zhang <qi.z.zhang@intel.com>
Acked-by: Beilei Xing <beilei.xing@intel.com>

RE: [PATCH] doc: refine iavf limitation or known issues

[Zhang, Qi Z]

> -----Original Message-----
> From: Xing, Beilei <beilei.xing@intel.com>
> Sent: Tuesday, September 13, 2022 3:49 PM
> To: Zhang, Qi Z <qi.z.zhang@intel.com>; Wu, Jingjing <jingjing.wu@intel.com>
> Cc: Yang, Qiming <qiming.yang@intel.com>; dev@dpdk.org
> Subject: RE: [PATCH] doc: refine iavf limitation or known issues
> 
> 
> 
> > -----Original Message-----
> > From: Zhang, Qi Z <qi.z.zhang@intel.com>
> > Sent: Tuesday, September 6, 2022 8:42 PM
> > To: Xing, Beilei <beilei.xing@intel.com>; Wu, Jingjing
> > <jingjing.wu@intel.com>
> > Cc: Yang, Qiming <qiming.yang@intel.com>; dev@dpdk.org; Zhang, Qi Z
> > <qi.z.zhang@intel.com>
> > Subject: [PATCH] doc: refine iavf limitation or known issues
> >
> > Move all VF related limitationi or known issues from i40e.rst to
> > intel_vf.rst, as i40evf has been removed from i40e, i40e.rst should
> > only cover PF's information.
> >
> > The patch also fix couple typos and refine the words to be more accurate.
> >
> > Signed-off-by: Qi Zhang <qi.z.zhang@intel.com>
> Acked-by: Beilei Xing <beilei.xing@intel.com>

Applied to dpdk-next-net-intel.

Thanks
Qi