* Re: [dpdk-dev] [PATCH] doc: clarify virtio PMD path selection
2019-11-18 10:29 [dpdk-dev] [PATCH] doc: clarify virtio PMD path selection Yinan
@ 2019-11-18 2:23 ` Stephen Hemminger
2019-11-25 15:49 ` Wang, Yinan
2019-11-18 9:55 ` Gavin Hu (Arm Technology China)
` (3 subsequent siblings)
4 siblings, 1 reply; 13+ messages in thread
From: Stephen Hemminger @ 2019-11-18 2:23 UTC (permalink / raw)
To: Yinan
Cc: dev, maxime.coquelin, tiwei.bie, zhihong.wang, john.mcnamara,
marko.kovacevic
On Mon, 18 Nov 2019 05:29:23 -0500
Yinan <yinan.wang@intel.com> wrote:
> From: Yinan Wang <yinan.wang@intel.com>
>
> add virtio paths selection and usage introduction for better
> virtio usability.
>
> Signed-off-by: Yinan Wang <yinan.wang@intel.com>
> ---
Nice to have this documented.
Do you think it would make sense to link to the virtio standard that defines this?
^ permalink raw reply [flat|nested] 13+ messages in thread* Re: [dpdk-dev] [PATCH] doc: clarify virtio PMD path selection
2019-11-18 2:23 ` Stephen Hemminger
@ 2019-11-25 15:49 ` Wang, Yinan
0 siblings, 0 replies; 13+ messages in thread
From: Wang, Yinan @ 2019-11-25 15:49 UTC (permalink / raw)
To: Stephen Hemminger
Cc: dev, maxime.coquelin, Bie, Tiwei, Wang, Zhihong, Mcnamara, John,
Kovacevic, Marko
Thanks your suggestion, I will add the link in v2 version.
> -----Original Message-----
> From: Stephen Hemminger <stephen@networkplumber.org>
> Sent: 2019年11月18日 10:24
> To: Wang, Yinan <yinan.wang@intel.com>
> Cc: dev@dpdk.org; maxime.coquelin@redhat.com; Bie, Tiwei
> <tiwei.bie@intel.com>; Wang, Zhihong <zhihong.wang@intel.com>;
> Mcnamara, John <john.mcnamara@intel.com>; Kovacevic, Marko
> <marko.kovacevic@intel.com>
> Subject: Re: [dpdk-dev] [PATCH] doc: clarify virtio PMD path selection
>
> On Mon, 18 Nov 2019 05:29:23 -0500
> Yinan <yinan.wang@intel.com> wrote:
>
> > From: Yinan Wang <yinan.wang@intel.com>
> >
> > add virtio paths selection and usage introduction for better virtio
> > usability.
> >
> > Signed-off-by: Yinan Wang <yinan.wang@intel.com>
> > ---
>
>
> Nice to have this documented.
> Do you think it would make sense to link to the virtio standard that defines this?
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [dpdk-dev] [PATCH] doc: clarify virtio PMD path selection
2019-11-18 10:29 [dpdk-dev] [PATCH] doc: clarify virtio PMD path selection Yinan
2019-11-18 2:23 ` Stephen Hemminger
@ 2019-11-18 9:55 ` Gavin Hu (Arm Technology China)
2019-11-26 16:08 ` [dpdk-dev] [PATCH v4] " Yinan
` (2 subsequent siblings)
4 siblings, 0 replies; 13+ messages in thread
From: Gavin Hu (Arm Technology China) @ 2019-11-18 9:55 UTC (permalink / raw)
To: Yinan, dev, maxime.coquelin, tiwei.bie
Cc: zhihong.wang, john.mcnamara, marko.kovacevic, nd
Hi Yinan,
> -----Original Message-----
> From: dev <dev-bounces@dpdk.org> On Behalf Of Yinan
> Sent: Monday, November 18, 2019 6:29 PM
> To: dev@dpdk.org; maxime.coquelin@redhat.com; tiwei.bie@intel.com
> Cc: zhihong.wang@intel.com; john.mcnamara@intel.com;
> marko.kovacevic@intel.com; Yinan Wang <yinan.wang@intel.com>
> Subject: [dpdk-dev] [PATCH] doc: clarify virtio PMD path selection
>
> From: Yinan Wang <yinan.wang@intel.com>
>
> add virtio paths selection and usage introduction for better
> virtio usability.
>
> Signed-off-by: Yinan Wang <yinan.wang@intel.com>
> ---
> .../virtio_paths_selection_and_usage.rst | 130 ++++++++++++++++++
> 1 file changed, 130 insertions(+)
> create mode 100644 doc/guides/howto/virtio_paths_selection_and_usage.rst
>
> diff --git a/doc/guides/howto/virtio_paths_selection_and_usage.rst
> b/doc/guides/howto/virtio_paths_selection_and_usage.rst
> new file mode 100644
> index 000000000..b5918eaf9
> --- /dev/null
> +++ b/doc/guides/howto/virtio_paths_selection_and_usage.rst
> @@ -0,0 +1,130 @@
> +.. SPDX-License-Identifier: BSD-3-Clause
> + Copyright(c) 2019 Intel Corporation.
> +
> +Virtio paths Selection and Usage
> +================================
> +
> +Logically virtio-PMD has 9 paths based on the virtio features (Rx
> mergeable,In-order,Packed virtqueue)
> +combinations, below are introduction of virtio three common features:
s/are/is an
> +
> +* Rx mergeable: With this feature negotiated, device can receive larger
> packets by combining
> + individual descriptors.
> +* In-order: Some devices always use descriptors in the same order in which
> they have been made
> + available, these devices can offer the VIRTIO_F_IN_ORDER feature. If this
> feature negotiated,
> + driver will use descriptors in order. Meanwhile, this knowledge allows
> device operate used ring
> + in batches and driver operate available ring in batches and such can
> decrease cache miss rate.
> +* Packed virtqueue: The structure of packed virtqueue is different from split
> virtqueue，split
> + virtqueue is composed of available ring, used ring and descriptor table,
> while packed virtqueue
> + is composed of descriptor ring，driver event suppression and device event
> suppression. The idea
> + behind this is to improve performance by avoiding cache misses and and
> make it easier for devices
> + to implement.
> +
> +Virtio paths Selection
> +----------------------
> +
> +If packed virtqueue is not negotiated, below split virtqueue paths can be
> selected
> +according to below configuration:
> +
> +#. Split virtqueue mergeable path: If Rx mergeable is negotiated, in-order
> feature is
> + not negotiated, this path will be selected.
> +#. Split virtqueue non-mergeable path: If Rx mergeable and in-order feature
> are not
> + negotiated, also Rx offload(s) are requested, this path can be selected.
> +#. Split virtqueue in-order mergeable path: If in-order feature and Rx
> mergeable are
> + both negotiated, this path can be selected.
> +#. Split virtqueue in-order non-mergeable path: If in-order feature is
> negotiated and
> + Rx mergeable is not negotiated, this path can be selected.
> +#. Split virtqueue vectorized RX path: If Rx mergeable is disabled and no Rx
> offload
> + requested, this path can be selected.
> +
> +If packed virtqueue is negotiated, below packed virtqueue paths can be
> selected
> +according to below configuration:
> +
> +#. Packed virtqueue mergeable path: If Rx mergeable is negotiated, in-order
> feature
> + is not negotiated, this path will be selected.
> +#. Packed virtqueue non-mergeable path: If Rx mergeable and in-order
> feature are not
> + negotiated, also Rx offload(s) are requested, this path will be selected.
> +#. Packed virtqueue in-order mergeable path: If in-order feature and Rx
> mergeable are
> + both negotiated, this path will be selected.
> +#. Packed virtqueue in-order non-mergeable path: If in-order feature is
> negotiated and
> + Rx mergeable is not negotiated, this path will be selected.
> +
> +Rx/Tx callbacks of each Virtio path
> +-----------------------------------
> +
> +Refer to above descriptions,virtio path and Rx/TX callbacks are auto selected
> by different parameters of
> +vdev and workloads. Rx callbacks and Tx callbacks name for each Virtio Path
> are shown in following tables::
> +
> + +-----------------------------------------------------------------------------------------------
> -----------+
> + | Virtio path | Rx callbacks | TX callbacks |
> + +-----------------------------------------------------------------------------------------------
> -----------+
> + |Split virtqueue mergeable path |virtio_recv_mergeable_pkts |
> virtio_xmit_pkts |
> + +-----------------------------------------------------------------------------------------------
> -----------+
> + |Split virtqueue non-mergeable path | virtio_recv_pkts |
> virtio_xmit_pkts |
> + +-----------------------------------------------------------------------------------------------
> -----------+
> + |Split virtqueue in-order mergeable path | virtio_recv_pkts_inorder |
> virtio_xmit_pkts_inorder|
> + +-----------------------------------------------------------------------------------------------
> -----------+
> + |Split virtqueue in-order non-mergeable path | virtio_recv_pkts_inorder
> | virtio_xmit_pkts_inorder|
> + +-----------------------------------------------------------------------------------------------
> -----------+
> + |Split virtqueue vectorized RX path | virtio_recv_pkts_vec |
> virtio_xmit_pkts |
> + +-----------------------------------------------------------------------------------------------
> -----------+
> + |Packed virtqueue mergeable path |
> virtio_recv_mergeable_pkts_packed| virtio_xmit_pkts_packed |
> + +-----------------------------------------------------------------------------------------------
> -----------+
> + |Packed virtqueue normal path | virtio_recv_pkts_packed |
> virtio_xmit_pkts_packed |
> + +-----------------------------------------------------------------------------------------------
> -----------+
> + |Packed virtqueue in-order mergeable path |
> virtio_recv_mergeable_pkts_packed| virtio_xmit_pkts_packed |
> + +-----------------------------------------------------------------------------------------------
> -----------+
> + |Packed virtqueue in-order normal path | virtio_recv_pkts_packed
> | virtio_xmit_pkts_packed |
> + +-----------------------------------------------------------------------------------------------
> -----------+
> +
> +Virtio paths Support Status from Release to Release
> +---------------------------------------------------
> +
> +Virtio feature implementation:
> +
> +* In-order feature implemented in DPDK 18.08 by adding new Rx/TX
> callbacks
> + ``virtio_recv_pkts_inorder`` and ``virtio_xmit_pkts_inorder``.
> +* Packed virtqueue implemented in DPDK 19.02 by adding new Rx/TX
> callbacks
> + ``virtio_recv_pkts_packed`` , ``virtio_recv_mergeable_pkts_packed`` and
> ``virtio_xmit_pkts_packed``.
> +
> +Virtio path number changes from release to release, all virtio paths support
> status are shown in below table::
> +
> + +-----------------------------------------------------------------------------------------------
> ---------------------------------------------------------+
> + |Virtio path\ DPDK version | v16.11 | v17.02 | v17.05 | v17.08 |
> v17.11 | v18.02 | v18.05 | v18.08 | v18.11 | v19.02 | v19.05 | v19.08 |
> + +-----------------------------------------------------------------------------------------------
> ---------------------------------------------------------+
> + |Split virtqueue mergebale path | Y | Y | Y | Y | Y | Y
> | Y | Y | Y | Y | Y | Y |
> + +-----------------------------------------------------------------------------------------------
> ---------------------------------------------------------+
> + |Split virtqueue non-mergeable path | Y | Y | Y | Y | Y | Y
> | Y | Y | Y | Y | Y | Y |
> + +-----------------------------------------------------------------------------------------------
> ---------------------------------------------------------+
> + |Split virtqueue vectorized RX path | Y | Y | Y | Y | Y | Y
> | Y | Y | Y | Y | Y | Y |
> + -------------------------------------------------------------------------------------------------
> --------------------------------------------------------+
> + |Split virtqueue simple TX path | Y | Y | Y | Y | Y | Y |
> Y | N | N | N | N | N |
> + -------------------------------------------------------------------------------------------------
> --------------------------------------------------------+
> + |Split virtqueue in-order non-mergeable path | | | | | |
> | | Y | Y | Y | Y | Y |
> + -------------------------------------------------------------------------------------------------
> --------------------------------------------------------+
> + |Split virtqueue in-order mergeable path | | | | | |
> | | Y | Y | Y | Y | Y |
> + -------------------------------------------------------------------------------------------------
> --------------------------------------------------------+
> + |Packed virtqueue mergeable path | | | | | | |
> | | | Y | Y | Y |
> + -------------------------------------------------------------------------------------------------
> --------------------------------------------------------+
> + |Packed virtqueue non-mergeable path | | | | | |
> | | | | Y | Y | Y |
> + -------------------------------------------------------------------------------------------------
> --------------------------------------------------------+
> + |Packed virtqueue in-order mergeable path | | | | | |
> | | | | Y | Y | Y |
> + -------------------------------------------------------------------------------------------------
> --------------------------------------------------------+
> + |Packed virtqueue in-order non-mergeable path| | | | |
> | | | | | Y | Y | Y |
> + -------------------------------------------------------------------------------------------------
> --------------------------------------------------------+
> +
> +QEMU Support Status
> +-------------------
It is better to add Qemu version latest, the future Qemu version may support more.
> +
> +Qemu only support three path of Virtio-PMD: Split virtqueue mergebale path,
Add "s" to the first path.
> +Split virtqueue no-mergeable path，Split virtqueue vectorized RX path.
> +
> +How to Debug
> +------------
> +
> +If you meet performance drop or some other issues after upgrading the driver
> +or configuration, below steps can help you identify which path you selected
> and
> +root cause faster.
> +
> +#. Run vhost/virtio test case;
> +#. Run "perf top" and check virtio Rx/tx callback names;
> +#. Identify which virtio path is selected refer to above table.
> --
> 2.17.1
Other than the minor comments,
Reviewed-by: Gavin Hu <gavin.hu@arm.com>
^ permalink raw reply [flat|nested] 13+ messages in thread* [dpdk-dev] [PATCH v4] doc: clarify virtio PMD path selection
2019-11-18 10:29 [dpdk-dev] [PATCH] doc: clarify virtio PMD path selection Yinan
2019-11-18 2:23 ` Stephen Hemminger
2019-11-18 9:55 ` Gavin Hu (Arm Technology China)
@ 2019-11-26 16:08 ` Yinan
2019-11-27 2:43 ` Tiwei Bie
2019-11-26 21:30 ` [dpdk-dev] [PATCH] " Thomas Monjalon
2019-11-27 15:19 ` [dpdk-dev] [PATCH v5] " Yinan
4 siblings, 1 reply; 13+ messages in thread
From: Yinan @ 2019-11-26 16:08 UTC (permalink / raw)
To: dev, maxime.coquelin, tiwei.bie
Cc: zhihong.wang, john.mcnamara, marko.kovacevic, Wang Yinan
From: Wang Yinan <yinan.wang@intel.com>
add virtio paths selection and usage introduction for better
virtio usability.
Signed-off-by: Wang Yinan <yinan.wang@intel.com>
---
doc/guides/howto/index.rst | 1 +
.../virtio_paths_selection_and_usage.rst | 142 ++++++++++++++++++
2 files changed, 143 insertions(+)
create mode 100644 doc/guides/howto/virtio_paths_selection_and_usage.rst
diff --git a/doc/guides/howto/index.rst b/doc/guides/howto/index.rst
index a4c131652..6edb8d5be 100644
--- a/doc/guides/howto/index.rst
+++ b/doc/guides/howto/index.rst
@@ -16,6 +16,7 @@ HowTo Guides
vfd
virtio_user_for_container_networking
virtio_user_as_exceptional_path
+ virtio_paths_selection_and_usage
packet_capture_framework
telemetry
debug_troubleshoot
diff --git a/doc/guides/howto/virtio_paths_selection_and_usage.rst b/doc/guides/howto/virtio_paths_selection_and_usage.rst
new file mode 100644
index 000000000..e22b18e14
--- /dev/null
+++ b/doc/guides/howto/virtio_paths_selection_and_usage.rst
@@ -0,0 +1,142 @@
+.. SPDX-License-Identifier: BSD-3-Clause
+ Copyright(c) 2019 Intel Corporation.
+
+Virtio paths Selection and Usage
+================================
+
+Logically virtio-PMD has 9 paths based on the combination of virtio features
+(Rx mergeable, In-order, Packed virtqueue), below is an introduction of virtio
+common features:
+
+* `Rx mergeable <https://docs.oasis-open.org/virtio/virtio/v1.1/cs01/
+ virtio-v1.1-cs01.html#x1-2140004>`_: With this feature negotiated, device
+ can receive larger packets by combining individual descriptors.
+* `In-order <https://docs.oasis-open.org/virtio/virtio/v1.1/cs01/
+ virtio-v1.1-cs01.html#x1-690008>`_: Some devices always use descriptors
+ in the same order in which they have been made available, these
+ devices can offer the VIRTIO_F_IN_ORDER feature. If this feature negotiated,
+ driver will use descriptors in order. Meanwhile, this knowledge allows device
+ operate used ring in batches and driver operate available ring in batches and
+ such can decrease cache miss rate.
+* `Packed virtqueue <https://docs.oasis-open.org/virtio/virtio/v1.1/cs01/
+ virtio-v1.1-cs01.html#x1-610007>`_: The structure of packed virtqueue is
+ different from split virtqueue, split virtqueue is composed of available ring,
+ used ring and descriptor table, while packed virtqueue is composed of descriptor
+ ring, driver event suppression and device event suppression. The idea behind
+ this is to improve performance by avoiding cache misses and and make it easier
+ for devices to implement.
+
+Virtio paths Selection
+----------------------
+
+If packed virtqueue is not negotiated, below split virtqueue paths will be selected
+according to below configuration:
+
+#. Split virtqueue mergeable path: If Rx mergeable is negotiated, in-order feature is
+ not negotiated, this path will be selected.
+#. Split virtqueue non-mergeable path: If Rx mergeable and in-order feature are not
+ negotiated, also Rx offload(s) are requested, this path will be selected.
+#. Split virtqueue in-order mergeable path: If Rx mergeable and in-order feature are
+ both negotiated, this path will be selected.
+#. Split virtqueue in-order non-mergeable path: If in-order feature is negotiated and
+ Rx mergeable is not negotiated, this path will be selected.
+#. Split virtqueue vectorized RX path: If Rx mergeable is disabled and no Rx offload
+ requested, this path will be selected.
+
+If packed virtqueue is negotiated, below packed virtqueue paths will be selected
+according to below configuration:
+
+#. Packed virtqueue mergeable path: If Rx mergeable is negotiated, in-order feature
+ is not negotiated, this path will be selected.
+#. Packed virtqueue non-mergeable path: If Rx mergeable and in-order feature are not
+ negotiated, this path will be selected.
+#. Packed virtqueue in-order mergeable path: If in-order and Rx mergeable feature are
+ both negotiated, this path will be selected.
+#. Packed virtqueue in-order non-mergeable path: If in-order feature is negotiated and
+ Rx mergeable is not negotiated, this path will be selected.
+
+Rx/Tx callbacks of each Virtio path
+-----------------------------------
+
+Refer to above descriptions, virtio path and Rx/TX callbacks are auto selected by
+different parameters of vdev and workloads. Rx callbacks and Tx callbacks name for
+each Virtio Path are shown in following tables::
+
+ +----------------------------------------------------------------------------------------------------------+
+ | Virtio path | Rx callbacks | TX callbacks |
+ +----------------------------------------------------------------------------------------------------------+
+ |Split virtqueue mergeable path |virtio_recv_mergeable_pkts | virtio_xmit_pkts |
+ +----------------------------------------------------------------------------------------------------------+
+ |Split virtqueue non-mergeable path | virtio_recv_pkts | virtio_xmit_pkts |
+ +----------------------------------------------------------------------------------------------------------+
+ |Split virtqueue in-order mergeable path | virtio_recv_pkts_inorder | virtio_xmit_pkts_inorder|
+ +----------------------------------------------------------------------------------------------------------+
+ |Split virtqueue in-order non-mergeable path | virtio_recv_pkts_inorder | virtio_xmit_pkts_inorder|
+ +----------------------------------------------------------------------------------------------------------+
+ |Split virtqueue vectorized RX path | virtio_recv_pkts_vec | virtio_xmit_pkts |
+ +----------------------------------------------------------------------------------------------------------+
+ |Packed virtqueue mergeable path | virtio_recv_mergeable_pkts_packed| virtio_xmit_pkts_packed |
+ +----------------------------------------------------------------------------------------------------------+
+ |Packed virtqueue normal path | virtio_recv_pkts_packed | virtio_xmit_pkts_packed |
+ +----------------------------------------------------------------------------------------------------------+
+ |Packed virtqueue in-order mergeable path | virtio_recv_mergeable_pkts_packed| virtio_xmit_pkts_packed |
+ +----------------------------------------------------------------------------------------------------------+
+ |Packed virtqueue in-order normal path | virtio_recv_pkts_packed | virtio_xmit_pkts_packed |
+ +----------------------------------------------------------------------------------------------------------+
+
+Virtio paths Support Status from Release to Release
+---------------------------------------------------
+
+Virtio feature implementation:
+
+* In-order feature implemented in DPDK 18.08 by adding new Rx/TX callbacks
+ ``virtio_recv_pkts_inorder`` and ``virtio_xmit_pkts_inorder``.
+* Packed virtqueue implemented in DPDK 19.02 by adding new Rx/TX callbacks
+ ``virtio_recv_pkts_packed`` , ``virtio_recv_mergeable_pkts_packed`` and
+ ``virtio_xmit_pkts_packed``.
+
+Virtio path number changes from release to release, all virtio paths support
+status are shown in below table::
+
+ +--------------------------------------------------------------------------------------------------------------------------------------------------------+
+ |Virtio path\ DPDK version | v16.11 | v17.02 | v17.05 | v17.08 | v17.11 | v18.02 | v18.05 | v18.08 | v18.11 | v19.02 | v19.05 | v19.08 |
+ +--------------------------------------------------------------------------------------------------------------------------------------------------------+
+ |Split virtqueue mergeable path | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y |
+ +--------------------------------------------------------------------------------------------------------------------------------------------------------+
+ |Split virtqueue non-mergeable path | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y |
+ +--------------------------------------------------------------------------------------------------------------------------------------------------------+
+ |Split virtqueue vectorized RX path | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y |
+ ---------------------------------------------------------------------------------------------------------------------------------------------------------+
+ |Split virtqueue simple TX path | Y | Y | Y | Y | Y | Y | Y | N | N | N | N | N |
+ ---------------------------------------------------------------------------------------------------------------------------------------------------------+
+ |Split virtqueue in-order non-mergeable path | | | | | | | | Y | Y | Y | Y | Y |
+ ---------------------------------------------------------------------------------------------------------------------------------------------------------+
+ |Split virtqueue in-order mergeable path | | | | | | | | Y | Y | Y | Y | Y |
+ ---------------------------------------------------------------------------------------------------------------------------------------------------------+
+ |Packed virtqueue mergeable path | | | | | | | | | | Y | Y | Y |
+ ---------------------------------------------------------------------------------------------------------------------------------------------------------+
+ |Packed virtqueue non-mergeable path | | | | | | | | | | Y | Y | Y |
+ ---------------------------------------------------------------------------------------------------------------------------------------------------------+
+ |Packed virtqueue in-order mergeable path | | | | | | | | | | Y | Y | Y |
+ ---------------------------------------------------------------------------------------------------------------------------------------------------------+
+ |Packed virtqueue in-order non-mergeable path| | | | | | | | | | Y | Y | Y |
+ ---------------------------------------------------------------------------------------------------------------------------------------------------------+
+
+QEMU Support Status
+-------------------
+
+* Qemu now supports three paths of split virtqueue: Split virtqueue mergeable path,
+ Split virtqueue non-mergeable path, Split virtqueue vectorized RX path.
+* Since qemu 4.2.0, Packed virtqueue mergeable path and Packed virtqueue non-mergeable
+ path can be supported.
+
+How to Debug
+------------
+
+If you meet performance drop or some other issues after upgrading the driver
+or configuration, below steps can help you identify which path you selected and
+root cause faster.
+
+#. Run vhost/virtio test case;
+#. Run "perf top" and check virtio Rx/tx callback names;
+#. Identify which virtio path is selected refer to above table.
--
2.17.1
^ permalink raw reply [flat|nested] 13+ messages in thread* Re: [dpdk-dev] [PATCH v4] doc: clarify virtio PMD path selection
2019-11-26 16:08 ` [dpdk-dev] [PATCH v4] " Yinan
@ 2019-11-27 2:43 ` Tiwei Bie
0 siblings, 0 replies; 13+ messages in thread
From: Tiwei Bie @ 2019-11-27 2:43 UTC (permalink / raw)
To: Yinan; +Cc: dev, maxime.coquelin, zhihong.wang, john.mcnamara, marko.kovacevic
On Tue, Nov 26, 2019 at 11:08:14AM -0500, Yinan wrote:
> From: Wang Yinan <yinan.wang@intel.com>
>
> add virtio paths selection and usage introduction for better
s/add/Add/
> virtio usability.
>
> Signed-off-by: Wang Yinan <yinan.wang@intel.com>
> ---
> doc/guides/howto/index.rst | 1 +
> .../virtio_paths_selection_and_usage.rst | 142 ++++++++++++++++++
> 2 files changed, 143 insertions(+)
> create mode 100644 doc/guides/howto/virtio_paths_selection_and_usage.rst
>
> diff --git a/doc/guides/howto/index.rst b/doc/guides/howto/index.rst
> index a4c131652..6edb8d5be 100644
> --- a/doc/guides/howto/index.rst
> +++ b/doc/guides/howto/index.rst
> @@ -16,6 +16,7 @@ HowTo Guides
> vfd
> virtio_user_for_container_networking
> virtio_user_as_exceptional_path
> + virtio_paths_selection_and_usage
> packet_capture_framework
> telemetry
> debug_troubleshoot
> diff --git a/doc/guides/howto/virtio_paths_selection_and_usage.rst b/doc/guides/howto/virtio_paths_selection_and_usage.rst
> new file mode 100644
> index 000000000..e22b18e14
> --- /dev/null
> +++ b/doc/guides/howto/virtio_paths_selection_and_usage.rst
> @@ -0,0 +1,142 @@
> +.. SPDX-License-Identifier: BSD-3-Clause
> + Copyright(c) 2019 Intel Corporation.
> +
> +Virtio paths Selection and Usage
> +================================
> +
> +Logically virtio-PMD has 9 paths based on the combination of virtio features
> +(Rx mergeable, In-order, Packed virtqueue), below is an introduction of virtio
> +common features:
s/virtio common features/these features/
> +
> +* `Rx mergeable <https://docs.oasis-open.org/virtio/virtio/v1.1/cs01/
> + virtio-v1.1-cs01.html#x1-2140004>`_: With this feature negotiated, device
> + can receive larger packets by combining individual descriptors.
> +* `In-order <https://docs.oasis-open.org/virtio/virtio/v1.1/cs01/
> + virtio-v1.1-cs01.html#x1-690008>`_: Some devices always use descriptors
> + in the same order in which they have been made available, these
> + devices can offer the VIRTIO_F_IN_ORDER feature. If this feature negotiated,
> + driver will use descriptors in order. Meanwhile, this knowledge allows device
> + operate used ring in batches and driver operate available ring in batches and
> + such can decrease cache miss rate.
> +* `Packed virtqueue <https://docs.oasis-open.org/virtio/virtio/v1.1/cs01/
> + virtio-v1.1-cs01.html#x1-610007>`_: The structure of packed virtqueue is
> + different from split virtqueue, split virtqueue is composed of available ring,
> + used ring and descriptor table, while packed virtqueue is composed of descriptor
> + ring, driver event suppression and device event suppression. The idea behind
> + this is to improve performance by avoiding cache misses and and make it easier
s/and and/and/
> + for devices to implement.
> +
> +Virtio paths Selection
> +----------------------
> +
> +If packed virtqueue is not negotiated, below split virtqueue paths will be selected
> +according to below configuration:
> +
> +#. Split virtqueue mergeable path: If Rx mergeable is negotiated, in-order feature is
> + not negotiated, this path will be selected.
> +#. Split virtqueue non-mergeable path: If Rx mergeable and in-order feature are not
> + negotiated, also Rx offload(s) are requested, this path will be selected.
> +#. Split virtqueue in-order mergeable path: If Rx mergeable and in-order feature are
> + both negotiated, this path will be selected.
> +#. Split virtqueue in-order non-mergeable path: If in-order feature is negotiated and
> + Rx mergeable is not negotiated, this path will be selected.
> +#. Split virtqueue vectorized RX path: If Rx mergeable is disabled and no Rx offload
s/RX/Rx/
> + requested, this path will be selected.
> +
> +If packed virtqueue is negotiated, below packed virtqueue paths will be selected
> +according to below configuration:
> +
> +#. Packed virtqueue mergeable path: If Rx mergeable is negotiated, in-order feature
> + is not negotiated, this path will be selected.
> +#. Packed virtqueue non-mergeable path: If Rx mergeable and in-order feature are not
> + negotiated, this path will be selected.
> +#. Packed virtqueue in-order mergeable path: If in-order and Rx mergeable feature are
> + both negotiated, this path will be selected.
> +#. Packed virtqueue in-order non-mergeable path: If in-order feature is negotiated and
> + Rx mergeable is not negotiated, this path will be selected.
> +
> +Rx/Tx callbacks of each Virtio path
> +-----------------------------------
> +
> +Refer to above descriptions, virtio path and Rx/TX callbacks are auto selected by
s/TX/Tx/
> +different parameters of vdev and workloads. Rx callbacks and Tx callbacks name for
> +each Virtio Path are shown in following tables::
s/in following tables::/in below table:/
> +
> + +----------------------------------------------------------------------------------------------------------+
> + | Virtio path | Rx callbacks | TX callbacks |
s/TX/Tx/
> + +----------------------------------------------------------------------------------------------------------+
> + |Split virtqueue mergeable path |virtio_recv_mergeable_pkts | virtio_xmit_pkts |
> + +----------------------------------------------------------------------------------------------------------+
> + |Split virtqueue non-mergeable path | virtio_recv_pkts | virtio_xmit_pkts |
> + +----------------------------------------------------------------------------------------------------------+
> + |Split virtqueue in-order mergeable path | virtio_recv_pkts_inorder | virtio_xmit_pkts_inorder|
> + +----------------------------------------------------------------------------------------------------------+
> + |Split virtqueue in-order non-mergeable path | virtio_recv_pkts_inorder | virtio_xmit_pkts_inorder|
> + +----------------------------------------------------------------------------------------------------------+
> + |Split virtqueue vectorized RX path | virtio_recv_pkts_vec | virtio_xmit_pkts |
s/RX/Rx/
> + +----------------------------------------------------------------------------------------------------------+
> + |Packed virtqueue mergeable path | virtio_recv_mergeable_pkts_packed| virtio_xmit_pkts_packed |
> + +----------------------------------------------------------------------------------------------------------+
> + |Packed virtqueue normal path | virtio_recv_pkts_packed | virtio_xmit_pkts_packed |
s/normal/non-mergeable/
> + +----------------------------------------------------------------------------------------------------------+
> + |Packed virtqueue in-order mergeable path | virtio_recv_mergeable_pkts_packed| virtio_xmit_pkts_packed |
> + +----------------------------------------------------------------------------------------------------------+
> + |Packed virtqueue in-order normal path | virtio_recv_pkts_packed | virtio_xmit_pkts_packed |
s/normal/non-mergeable/
> + +----------------------------------------------------------------------------------------------------------+
It seems above table will be interpreted as code block.
You can use below table:
.. table:: Virtio Paths and Callbacks
============================================ ================================= ========================
Virtio paths Rx callbacks Tx callbacks
============================================ ================================= ========================
Split virtqueue mergeable path virtio_recv_mergeable_pkts virtio_xmit_pkts
Split virtqueue non-mergeable path virtio_recv_pkts virtio_xmit_pkts
Split virtqueue in-order mergeable path virtio_recv_pkts_inorder virtio_xmit_pkts_inorder
Split virtqueue in-order non-mergeable path virtio_recv_pkts_inorder virtio_xmit_pkts_inorder
Split virtqueue vectorized Rx path virtio_recv_pkts_vec virtio_xmit_pkts
Packed virtqueue mergeable path virtio_recv_mergeable_pkts_packed virtio_xmit_pkts_packed
Packed virtqueue non-meregable path virtio_recv_pkts_packed virtio_xmit_pkts_packed
Packed virtqueue in-order mergeable path virtio_recv_mergeable_pkts_packed virtio_xmit_pkts_packed
Packed virtqueue in-order non-mergeable path virtio_recv_pkts_packed virtio_xmit_pkts_packed
============================================ ================================= ========================
> +
> +Virtio paths Support Status from Release to Release
> +---------------------------------------------------
> +
> +Virtio feature implementation:
> +
> +* In-order feature implemented in DPDK 18.08 by adding new Rx/TX callbacks
s/TX/Tx/
s/implemented in/is supported since/
> + ``virtio_recv_pkts_inorder`` and ``virtio_xmit_pkts_inorder``.
> +* Packed virtqueue implemented in DPDK 19.02 by adding new Rx/TX callbacks
Ditto.
> + ``virtio_recv_pkts_packed`` , ``virtio_recv_mergeable_pkts_packed`` and
> + ``virtio_xmit_pkts_packed``.
> +
> +Virtio path number changes from release to release, all virtio paths support
> +status are shown in below table::
> +
> + +--------------------------------------------------------------------------------------------------------------------------------------------------------+
> + |Virtio path\ DPDK version | v16.11 | v17.02 | v17.05 | v17.08 | v17.11 | v18.02 | v18.05 | v18.08 | v18.11 | v19.02 | v19.05 | v19.08 |
> + +--------------------------------------------------------------------------------------------------------------------------------------------------------+
> + |Split virtqueue mergeable path | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y |
> + +--------------------------------------------------------------------------------------------------------------------------------------------------------+
> + |Split virtqueue non-mergeable path | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y |
> + +--------------------------------------------------------------------------------------------------------------------------------------------------------+
> + |Split virtqueue vectorized RX path | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y |
> + ---------------------------------------------------------------------------------------------------------------------------------------------------------+
> + |Split virtqueue simple TX path | Y | Y | Y | Y | Y | Y | Y | N | N | N | N | N |
> + ---------------------------------------------------------------------------------------------------------------------------------------------------------+
> + |Split virtqueue in-order non-mergeable path | | | | | | | | Y | Y | Y | Y | Y |
> + ---------------------------------------------------------------------------------------------------------------------------------------------------------+
> + |Split virtqueue in-order mergeable path | | | | | | | | Y | Y | Y | Y | Y |
> + ---------------------------------------------------------------------------------------------------------------------------------------------------------+
> + |Packed virtqueue mergeable path | | | | | | | | | | Y | Y | Y |
> + ---------------------------------------------------------------------------------------------------------------------------------------------------------+
> + |Packed virtqueue non-mergeable path | | | | | | | | | | Y | Y | Y |
> + ---------------------------------------------------------------------------------------------------------------------------------------------------------+
> + |Packed virtqueue in-order mergeable path | | | | | | | | | | Y | Y | Y |
> + ---------------------------------------------------------------------------------------------------------------------------------------------------------+
> + |Packed virtqueue in-order non-mergeable path| | | | | | | | | | Y | Y | Y |
> + ---------------------------------------------------------------------------------------------------------------------------------------------------------+
19.11 can be included in above table as well.
Columns can be merged if possible.
You can do it like this:
.. table:: Virtio Paths and Releases
============================================ ============= ============= =============
Virtio paths 16.11 ~ 18.05 18.08 ~ 18.11 19.02 ~ 19.11
============================================ ============= ============= =============
Split virtqueue mergeable path Y Y Y
Split virtqueue non-mergeable path Y Y Y
Split virtqueue vectorized Rx path Y Y Y
Split virtqueue simple Tx path Y N N
Split virtqueue in-order mergeable path Y Y
Split virtqueue in-order non-mergeable path Y Y
Packed virtqueue mergeable path Y
Packed virtqueue non-mergeable path Y
Packed virtqueue in-order mergeable path Y
Packed virtqueue in-order non-mergeable path Y
============================================ ============= ============= =============
> +
> +QEMU Support Status
> +-------------------
> +
> +* Qemu now supports three paths of split virtqueue: Split virtqueue mergeable path,
> + Split virtqueue non-mergeable path, Split virtqueue vectorized RX path.
s/RX/Rx/
> +* Since qemu 4.2.0, Packed virtqueue mergeable path and Packed virtqueue non-mergeable
> + path can be supported.
> +
> +How to Debug
> +------------
> +
> +If you meet performance drop or some other issues after upgrading the driver
> +or configuration, below steps can help you identify which path you selected and
> +root cause faster.
> +
> +#. Run vhost/virtio test case;
> +#. Run "perf top" and check virtio Rx/tx callback names;
> +#. Identify which virtio path is selected refer to above table.
> --
> 2.17.1
>
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [dpdk-dev] [PATCH] doc: clarify virtio PMD path selection
2019-11-18 10:29 [dpdk-dev] [PATCH] doc: clarify virtio PMD path selection Yinan
` (2 preceding siblings ...)
2019-11-26 16:08 ` [dpdk-dev] [PATCH v4] " Yinan
@ 2019-11-26 21:30 ` Thomas Monjalon
2019-11-27 15:19 ` [dpdk-dev] [PATCH v5] " Yinan
4 siblings, 0 replies; 13+ messages in thread
From: Thomas Monjalon @ 2019-11-26 21:30 UTC (permalink / raw)
To: Yinan
Cc: dev, maxime.coquelin, tiwei.bie, zhihong.wang, john.mcnamara,
marko.kovacevic
18/11/2019 11:29, Yinan:
+--------------------------------------------------------------------------------------------------------------------------------------------------------+
> + |Virtio path\ DPDK version | v16.11 | v17.02 | v17.05 | v17.08 | v17.11 | v18.02 | v18.05 | v18.08 | v18.11 | v19.02 | v19.05 | v19.08 |
> + +--------------------------------------------------------------------------------------------------------------------------------------------------------+
> + |Split virtqueue mergebale path | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y |
> + +--------------------------------------------------------------------------------------------------------------------------------------------------------+
> + |Split virtqueue non-mergeable path | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y |
> + +--------------------------------------------------------------------------------------------------------------------------------------------------------+
> + |Split virtqueue vectorized RX path | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y |
> + ---------------------------------------------------------------------------------------------------------------------------------------------------------+
> + |Split virtqueue simple TX path | Y | Y | Y | Y | Y | Y | Y | N | N | N | N | N |
> + ---------------------------------------------------------------------------------------------------------------------------------------------------------+
> + |Split virtqueue in-order non-mergeable path | | | | | | | | Y | Y | Y | Y | Y |
> + ---------------------------------------------------------------------------------------------------------------------------------------------------------+
> + |Split virtqueue in-order mergeable path | | | | | | | | Y | Y | Y | Y | Y |
> + ---------------------------------------------------------------------------------------------------------------------------------------------------------+
> + |Packed virtqueue mergeable path | | | | | | | | | | Y | Y | Y |
> + ---------------------------------------------------------------------------------------------------------------------------------------------------------+
> + |Packed virtqueue non-mergeable path | | | | | | | | | | Y | Y | Y |
> + ---------------------------------------------------------------------------------------------------------------------------------------------------------+
> + |Packed virtqueue in-order mergeable path | | | | | | | | | | Y | Y | Y |
> + ---------------------------------------------------------------------------------------------------------------------------------------------------------+
> + |Packed virtqueue in-order non-mergeable path| | | | | | | | | | Y | Y | Y |
> + ---------------------------------------------------------------------------------------------------------------------------------------------------------+
Please try to make the table shorter.
I think there would be some gain to name versions without "v"
and use a simple table syntax:
http://docutils.sourceforge.net/docs/user/rst/quickref.html#tables
^ permalink raw reply [flat|nested] 13+ messages in thread* [dpdk-dev] [PATCH v5] doc: clarify virtio PMD path selection
2019-11-18 10:29 [dpdk-dev] [PATCH] doc: clarify virtio PMD path selection Yinan
` (3 preceding siblings ...)
2019-11-26 21:30 ` [dpdk-dev] [PATCH] " Thomas Monjalon
@ 2019-11-27 15:19 ` Yinan
2019-11-27 6:38 ` Tiwei Bie
` (3 more replies)
4 siblings, 4 replies; 13+ messages in thread
From: Yinan @ 2019-11-27 15:19 UTC (permalink / raw)
To: dev, maxime.coquelin, tiwei.bie
Cc: zhihong.wang, john.mcnamara, marko.kovacevic, Yinan Wang
From: Yinan Wang <yinan.wang@intel.com>
Add virtio paths selection and usage introduction for better
virtio usability.
Signed-off-by: Yinan Wang <yinan.wang@intel.com>
---
doc/guides/howto/index.rst | 1 +
.../virtio_paths_selection_and_usage.rst | 126 ++++++++++++++++++
2 files changed, 127 insertions(+)
create mode 100644 doc/guides/howto/virtio_paths_selection_and_usage.rst
diff --git a/doc/guides/howto/index.rst b/doc/guides/howto/index.rst
index a4c131652..6edb8d5be 100644
--- a/doc/guides/howto/index.rst
+++ b/doc/guides/howto/index.rst
@@ -16,6 +16,7 @@ HowTo Guides
vfd
virtio_user_for_container_networking
virtio_user_as_exceptional_path
+ virtio_paths_selection_and_usage
packet_capture_framework
telemetry
debug_troubleshoot
diff --git a/doc/guides/howto/virtio_paths_selection_and_usage.rst b/doc/guides/howto/virtio_paths_selection_and_usage.rst
new file mode 100644
index 000000000..9bf7f8ef7
--- /dev/null
+++ b/doc/guides/howto/virtio_paths_selection_and_usage.rst
@@ -0,0 +1,126 @@
+.. SPDX-License-Identifier: BSD-3-Clause
+ Copyright(c) 2019 Intel Corporation.
+
+Virtio paths Selection and Usage
+================================
+
+Logically virtio-PMD has 9 paths based on the combination of virtio features
+(Rx mergeable, In-order, Packed virtqueue), below is an introduction of these
+features:
+
+* `Rx mergeable <https://docs.oasis-open.org/virtio/virtio/v1.1/cs01/
+ virtio-v1.1-cs01.html#x1-2140004>`_: With this feature negotiated, device
+ can receive large packets by combining individual descriptors.
+* `In-order <https://docs.oasis-open.org/virtio/virtio/v1.1/cs01/
+ virtio-v1.1-cs01.html#x1-690008>`_: Some devices always use descriptors
+ in the same order in which they have been made available, these
+ devices can offer the VIRTIO_F_IN_ORDER feature. With this feature negotiated,
+ driver will use descriptors in order.
+* `Packed virtqueue <https://docs.oasis-open.org/virtio/virtio/v1.1/cs01/
+ virtio-v1.1-cs01.html#x1-610007>`_: The structure of packed virtqueue is
+ different from split virtqueue, split virtqueue is composed of available ring,
+ used ring and descriptor table, while packed virtqueue is composed of descriptor
+ ring, driver event suppression and device event suppression. The idea behind
+ this is to improve performance by avoiding cache misses and make it easier
+ for hardware to implement.
+
+Virtio paths Selection
+----------------------
+
+If packed virtqueue is not negotiated, below split virtqueue paths will be selected
+according to below configuration:
+
+#. Split virtqueue mergeable path: If Rx mergeable is negotiated, in-order feature is
+ not negotiated, this path will be selected.
+#. Split virtqueue non-mergeable path: If Rx mergeable and in-order feature are not
+ negotiated, also Rx offload(s) are requested, this path will be selected.
+#. Split virtqueue in-order mergeable path: If Rx mergeable and in-order feature are
+ both negotiated, this path will be selected.
+#. Split virtqueue in-order non-mergeable path: If in-order feature is negotiated and
+ Rx mergeable is not negotiated, this path will be selected.
+#. Split virtqueue vectorized Rx path: If Rx mergeable is disabled and no Rx offload
+ requested, this path will be selected.
+
+If packed virtqueue is negotiated, below packed virtqueue paths will be selected
+according to below configuration:
+
+#. Packed virtqueue mergeable path: If Rx mergeable is negotiated, in-order feature
+ is not negotiated, this path will be selected.
+#. Packed virtqueue non-mergeable path: If Rx mergeable and in-order feature are not
+ negotiated, this path will be selected.
+#. Packed virtqueue in-order mergeable path: If in-order and Rx mergeable feature are
+ both negotiated, this path will be selected.
+#. Packed virtqueue in-order non-mergeable path: If in-order feature is negotiated and
+ Rx mergeable is not negotiated, this path will be selected.
+
+Rx/Tx callbacks of each Virtio path
+-----------------------------------
+
+Refer to above description, virtio path and corresponding Rx/Tx callbacks will
+be selected automatically. Rx callbacks and Tx callbacks for each virtio path
+are shown in below table:
+
+.. table:: Virtio Paths and Callbacks
+
+ ============================================ ================================= ========================
+ Virtio paths Rx callbacks Tx callbacks
+ ============================================ ================================= ========================
+ Split virtqueue mergeable path virtio_recv_mergeable_pkts virtio_xmit_pkts
+ Split virtqueue non-mergeable path virtio_recv_pkts virtio_xmit_pkts
+ Split virtqueue in-order mergeable path virtio_recv_pkts_inorder virtio_xmit_pkts_inorder
+ Split virtqueue in-order non-mergeable path virtio_recv_pkts_inorder virtio_xmit_pkts_inorder
+ Split virtqueue vectorized Rx path virtio_recv_pkts_vec virtio_xmit_pkts
+ Packed virtqueue mergeable path virtio_recv_mergeable_pkts_packed virtio_xmit_pkts_packed
+ Packed virtqueue non-meregable path virtio_recv_pkts_packed virtio_xmit_pkts_packed
+ Packed virtqueue in-order mergeable path virtio_recv_mergeable_pkts_packed virtio_xmit_pkts_packed
+ Packed virtqueue in-order non-mergeable path virtio_recv_pkts_packed virtio_xmit_pkts_packed
+ ============================================ ================================= ========================
+
+Virtio paths Support Status from Release to Release
+---------------------------------------------------
+
+Virtio feature implementation:
+
+* In-order feature is supported since DPDK 18.08 by adding new Rx/Tx callbacks
+ ``virtio_recv_pkts_inorder`` and ``virtio_xmit_pkts_inorder``.
+* Packed virtqueue is supported since DPDK 19.02 by adding new Rx/Tx callbacks
+ ``virtio_recv_pkts_packed`` , ``virtio_recv_mergeable_pkts_packed`` and
+ ``virtio_xmit_pkts_packed``.
+
+All virtio paths support status are shown in below table:
+
+.. table:: Virtio Paths and Releases
+
+ ============================================ ============= ============= =============
+ Virtio paths 16.11 ~ 18.05 18.08 ~ 18.11 19.02 ~ 19.11
+ ============================================ ============= ============= =============
+ Split virtqueue mergeable path Y Y Y
+ Split virtqueue non-mergeable path Y Y Y
+ Split virtqueue vectorized Rx path Y Y Y
+ Split virtqueue simple Tx path Y N N
+ Split virtqueue in-order mergeable path Y Y
+ Split virtqueue in-order non-mergeable path Y Y
+ Packed virtqueue mergeable path Y
+ Packed virtqueue non-mergeable path Y
+ Packed virtqueue in-order mergeable path Y
+ Packed virtqueue in-order non-mergeable path Y
+ ============================================ ============= ============= =============
+
+QEMU Support Status
+-------------------
+
+* Qemu now supports three paths of split virtqueue: Split virtqueue mergeable path,
+ Split virtqueue non-mergeable path, Split virtqueue vectorized Rx path.
+* Since qemu 4.2.0, Packed virtqueue mergeable path and Packed virtqueue non-mergeable
+ path can be supported.
+
+How to Debug
+------------
+
+If you meet performance drop or some other issues after upgrading the driver
+or configuration, below steps can help you identify which path you selected and
+root cause faster.
+
+#. Run vhost/virtio test case;
+#. Run "perf top" and check virtio Rx/Tx callback names;
+#. Identify which virtio path is selected refer to above table.
--
2.17.1
^ permalink raw reply [flat|nested] 13+ messages in thread* Re: [dpdk-dev] [PATCH v5] doc: clarify virtio PMD path selection
2019-11-27 15:19 ` [dpdk-dev] [PATCH v5] " Yinan
@ 2019-11-27 6:38 ` Tiwei Bie
2019-11-27 8:41 ` Maxime Coquelin
` (2 subsequent siblings)
3 siblings, 0 replies; 13+ messages in thread
From: Tiwei Bie @ 2019-11-27 6:38 UTC (permalink / raw)
To: Yinan; +Cc: dev, maxime.coquelin, zhihong.wang, john.mcnamara, marko.kovacevic
On Wed, Nov 27, 2019 at 10:19:52AM -0500, Yinan wrote:
> From: Yinan Wang <yinan.wang@intel.com>
>
> Add virtio paths selection and usage introduction for better
> virtio usability.
>
> Signed-off-by: Yinan Wang <yinan.wang@intel.com>
> ---
> doc/guides/howto/index.rst | 1 +
> .../virtio_paths_selection_and_usage.rst | 126 ++++++++++++++++++
> 2 files changed, 127 insertions(+)
> create mode 100644 doc/guides/howto/virtio_paths_selection_and_usage.rst
Acked-by: Tiwei Bie <tiwei.bie@intel.com>
^ permalink raw reply [flat|nested] 13+ messages in thread* Re: [dpdk-dev] [PATCH v5] doc: clarify virtio PMD path selection
2019-11-27 15:19 ` [dpdk-dev] [PATCH v5] " Yinan
2019-11-27 6:38 ` Tiwei Bie
@ 2019-11-27 8:41 ` Maxime Coquelin
2019-11-28 0:14 ` Thomas Monjalon
2019-11-28 14:30 ` [dpdk-dev] [PATCH v6] " Maxime Coquelin
3 siblings, 0 replies; 13+ messages in thread
From: Maxime Coquelin @ 2019-11-27 8:41 UTC (permalink / raw)
To: Yinan, dev, tiwei.bie; +Cc: zhihong.wang, john.mcnamara, marko.kovacevic
On 11/27/19 4:19 PM, Yinan wrote:
> From: Yinan Wang <yinan.wang@intel.com>
>
> Add virtio paths selection and usage introduction for better
> virtio usability.
>
> Signed-off-by: Yinan Wang <yinan.wang@intel.com>
> ---
> doc/guides/howto/index.rst | 1 +
> .../virtio_paths_selection_and_usage.rst | 126 ++++++++++++++++++
> 2 files changed, 127 insertions(+)
> create mode 100644 doc/guides/howto/virtio_paths_selection_and_usage.rst
>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Thanks,
Maxime
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [dpdk-dev] [PATCH v5] doc: clarify virtio PMD path selection
2019-11-27 15:19 ` [dpdk-dev] [PATCH v5] " Yinan
2019-11-27 6:38 ` Tiwei Bie
2019-11-27 8:41 ` Maxime Coquelin
@ 2019-11-28 0:14 ` Thomas Monjalon
2019-11-28 14:30 ` [dpdk-dev] [PATCH v6] " Maxime Coquelin
3 siblings, 0 replies; 13+ messages in thread
From: Thomas Monjalon @ 2019-11-28 0:14 UTC (permalink / raw)
To: Yinan
Cc: dev, maxime.coquelin, tiwei.bie, zhihong.wang, john.mcnamara,
marko.kovacevic
27/11/2019 16:19, Yinan:
> From: Yinan Wang <yinan.wang@intel.com>
>
> Add virtio paths selection and usage introduction for better
> virtio usability.
>
> Signed-off-by: Yinan Wang <yinan.wang@intel.com>
> ---
> doc/guides/howto/index.rst | 1 +
> .../virtio_paths_selection_and_usage.rst | 126 ++++++++++++++++++
I don't understand why this doc is added in howto guides,
and not in doc/guides/nics/virtio.rst ?
^ permalink raw reply [flat|nested] 13+ messages in thread
* [dpdk-dev] [PATCH v6] doc: clarify virtio PMD path selection
2019-11-27 15:19 ` [dpdk-dev] [PATCH v5] " Yinan
` (2 preceding siblings ...)
2019-11-28 0:14 ` Thomas Monjalon
@ 2019-11-28 14:30 ` Maxime Coquelin
2019-11-28 18:17 ` Thomas Monjalon
3 siblings, 1 reply; 13+ messages in thread
From: Maxime Coquelin @ 2019-11-28 14:30 UTC (permalink / raw)
To: dev; +Cc: thomas, Yinan Wang, Tiwei Bie, Maxime Coquelin
From: Yinan Wang <yinan.wang@intel.com>
Add virtio paths selection and usage introduction for better
virtio usability.
Signed-off-by: Yinan Wang <yinan.wang@intel.com>
Acked-by: Tiwei Bie <tiwei.bie@intel.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
---
v6:
- Move to Virtio NIC documentation
doc/guides/nics/virtio.rst | 124 +++++++++++++++++++++++++++++++++++++
1 file changed, 124 insertions(+)
diff --git a/doc/guides/nics/virtio.rst b/doc/guides/nics/virtio.rst
index fb378a4b94..d1f5fb8986 100644
--- a/doc/guides/nics/virtio.rst
+++ b/doc/guides/nics/virtio.rst
@@ -402,3 +402,127 @@ Below devargs are supported by the virtio-user vdev:
It is used to enable virtio device packed virtqueue feature.
(Default: 0 (disabled))
+
+Virtio paths Selection and Usage
+--------------------------------
+
+Logically virtio-PMD has 9 paths based on the combination of virtio features
+(Rx mergeable, In-order, Packed virtqueue), below is an introduction of these
+features:
+
+* `Rx mergeable <https://docs.oasis-open.org/virtio/virtio/v1.1/cs01/
+ virtio-v1.1-cs01.html#x1-2140004>`_: With this feature negotiated, device
+ can receive large packets by combining individual descriptors.
+* `In-order <https://docs.oasis-open.org/virtio/virtio/v1.1/cs01/
+ virtio-v1.1-cs01.html#x1-690008>`_: Some devices always use descriptors
+ in the same order in which they have been made available, these
+ devices can offer the VIRTIO_F_IN_ORDER feature. With this feature negotiated,
+ driver will use descriptors in order.
+* `Packed virtqueue <https://docs.oasis-open.org/virtio/virtio/v1.1/cs01/
+ virtio-v1.1-cs01.html#x1-610007>`_: The structure of packed virtqueue is
+ different from split virtqueue, split virtqueue is composed of available ring,
+ used ring and descriptor table, while packed virtqueue is composed of descriptor
+ ring, driver event suppression and device event suppression. The idea behind
+ this is to improve performance by avoiding cache misses and make it easier
+ for hardware to implement.
+
+Virtio paths Selection
+~~~~~~~~~~~~~~~~~~~~~~
+
+If packed virtqueue is not negotiated, below split virtqueue paths will be selected
+according to below configuration:
+
+#. Split virtqueue mergeable path: If Rx mergeable is negotiated, in-order feature is
+ not negotiated, this path will be selected.
+#. Split virtqueue non-mergeable path: If Rx mergeable and in-order feature are not
+ negotiated, also Rx offload(s) are requested, this path will be selected.
+#. Split virtqueue in-order mergeable path: If Rx mergeable and in-order feature are
+ both negotiated, this path will be selected.
+#. Split virtqueue in-order non-mergeable path: If in-order feature is negotiated and
+ Rx mergeable is not negotiated, this path will be selected.
+#. Split virtqueue vectorized Rx path: If Rx mergeable is disabled and no Rx offload
+ requested, this path will be selected.
+
+If packed virtqueue is negotiated, below packed virtqueue paths will be selected
+according to below configuration:
+
+#. Packed virtqueue mergeable path: If Rx mergeable is negotiated, in-order feature
+ is not negotiated, this path will be selected.
+#. Packed virtqueue non-mergeable path: If Rx mergeable and in-order feature are not
+ negotiated, this path will be selected.
+#. Packed virtqueue in-order mergeable path: If in-order and Rx mergeable feature are
+ both negotiated, this path will be selected.
+#. Packed virtqueue in-order non-mergeable path: If in-order feature is negotiated and
+ Rx mergeable is not negotiated, this path will be selected.
+
+Rx/Tx callbacks of each Virtio path
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Refer to above description, virtio path and corresponding Rx/Tx callbacks will
+be selected automatically. Rx callbacks and Tx callbacks for each virtio path
+are shown in below table:
+
+.. table:: Virtio Paths and Callbacks
+
+ ============================================ ================================= ========================
+ Virtio paths Rx callbacks Tx callbacks
+ ============================================ ================================= ========================
+ Split virtqueue mergeable path virtio_recv_mergeable_pkts virtio_xmit_pkts
+ Split virtqueue non-mergeable path virtio_recv_pkts virtio_xmit_pkts
+ Split virtqueue in-order mergeable path virtio_recv_pkts_inorder virtio_xmit_pkts_inorder
+ Split virtqueue in-order non-mergeable path virtio_recv_pkts_inorder virtio_xmit_pkts_inorder
+ Split virtqueue vectorized Rx path virtio_recv_pkts_vec virtio_xmit_pkts
+ Packed virtqueue mergeable path virtio_recv_mergeable_pkts_packed virtio_xmit_pkts_packed
+ Packed virtqueue non-meregable path virtio_recv_pkts_packed virtio_xmit_pkts_packed
+ Packed virtqueue in-order mergeable path virtio_recv_mergeable_pkts_packed virtio_xmit_pkts_packed
+ Packed virtqueue in-order non-mergeable path virtio_recv_pkts_packed virtio_xmit_pkts_packed
+ ============================================ ================================= ========================
+
+Virtio paths Support Status from Release to Release
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Virtio feature implementation:
+
+* In-order feature is supported since DPDK 18.08 by adding new Rx/Tx callbacks
+ ``virtio_recv_pkts_inorder`` and ``virtio_xmit_pkts_inorder``.
+* Packed virtqueue is supported since DPDK 19.02 by adding new Rx/Tx callbacks
+ ``virtio_recv_pkts_packed`` , ``virtio_recv_mergeable_pkts_packed`` and
+ ``virtio_xmit_pkts_packed``.
+
+All virtio paths support status are shown in below table:
+
+.. table:: Virtio Paths and Releases
+
+ ============================================ ============= ============= =============
+ Virtio paths 16.11 ~ 18.05 18.08 ~ 18.11 19.02 ~ 19.11
+ ============================================ ============= ============= =============
+ Split virtqueue mergeable path Y Y Y
+ Split virtqueue non-mergeable path Y Y Y
+ Split virtqueue vectorized Rx path Y Y Y
+ Split virtqueue simple Tx path Y N N
+ Split virtqueue in-order mergeable path Y Y
+ Split virtqueue in-order non-mergeable path Y Y
+ Packed virtqueue mergeable path Y
+ Packed virtqueue non-mergeable path Y
+ Packed virtqueue in-order mergeable path Y
+ Packed virtqueue in-order non-mergeable path Y
+ ============================================ ============= ============= =============
+
+QEMU Support Status
+~~~~~~~~~~~~~~~~~~~
+
+* Qemu now supports three paths of split virtqueue: Split virtqueue mergeable path,
+ Split virtqueue non-mergeable path, Split virtqueue vectorized Rx path.
+* Since qemu 4.2.0, Packed virtqueue mergeable path and Packed virtqueue non-mergeable
+ path can be supported.
+
+How to Debug
+~~~~~~~~~~~~
+
+If you meet performance drop or some other issues after upgrading the driver
+or configuration, below steps can help you identify which path you selected and
+root cause faster.
+
+#. Run vhost/virtio test case;
+#. Run "perf top" and check virtio Rx/Tx callback names;
+#. Identify which virtio path is selected refer to above table.
--
2.21.0
^ permalink raw reply [flat|nested] 13+ messages in thread* Re: [dpdk-dev] [PATCH v6] doc: clarify virtio PMD path selection
2019-11-28 14:30 ` [dpdk-dev] [PATCH v6] " Maxime Coquelin
@ 2019-11-28 18:17 ` Thomas Monjalon
0 siblings, 0 replies; 13+ messages in thread
From: Thomas Monjalon @ 2019-11-28 18:17 UTC (permalink / raw)
To: Maxime Coquelin; +Cc: dev, Yinan Wang, Tiwei Bie
28/11/2019 15:30, Maxime Coquelin:
> From: Yinan Wang <yinan.wang@intel.com>
>
> Add virtio paths selection and usage introduction for better
> virtio usability.
>
> Signed-off-by: Yinan Wang <yinan.wang@intel.com>
> Acked-by: Tiwei Bie <tiwei.bie@intel.com>
> Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Applied, thanks
^ permalink raw reply [flat|nested] 13+ messages in thread