[ovs-dev] [PATCH v9 08/16] docs/dpdk/bridge: Add dpif performance section.

Harry van Haaren harry.van.haaren at intel.com
Fri Feb 12 17:17:10 UTC 2021


From: Cian Ferriter <cian.ferriter at intel.com>

This section details how two new commands can be used to list and select
the different dpif implementations. It also details how a non default
dpif implementation can be tested with the OVS unit test suite.

Add NEWS updates for the dpif-netdev.c refactor and the new dpif
implementations/commands.

Signed-off-by: Cian Ferriter <cian.ferriter at intel.com>

---

v8:
- Merge NEWS file items into one Userspace Datapath: heading
---
 Documentation/topics/dpdk/bridge.rst | 37 ++++++++++++++++++++++++++++
 NEWS                                 |  6 ++++-
 2 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/Documentation/topics/dpdk/bridge.rst b/Documentation/topics/dpdk/bridge.rst
index 526d5c959..ca90d7bdb 100644
--- a/Documentation/topics/dpdk/bridge.rst
+++ b/Documentation/topics/dpdk/bridge.rst
@@ -214,3 +214,40 @@ implementation ::
 
 Compile OVS in debug mode to have `ovs_assert` statements error out if
 there is a mis-match in the DPCLS lookup implementation.
+
+Datapath Interface Performance
+------------------------------
+
+The datapath interface (DPIF) or dp_netdev_input() is responsible for taking
+packets through the major components of the userspace datapath; such as
+miniflow_extract, EMC, SMC and DPCLS lookups, and a lot of the performance
+stats associated with the datapath.
+
+Just like with the SIMD DPCLS work above, SIMD can be applied to the DPIF to
+improve performance.
+
+OVS provides multiple implementations of the DPIF. These can be listed with the
+following command ::
+
+    $ ovs-appctl dpif-netdev/dpif-get
+    Available DPIF implementations:
+      dpif_scalar
+      dpif_avx512
+
+By default, dpif_scalar is used. The DPIF implementation can be selected by
+name ::
+
+    $ ovs-appctl dpif-netdev/dpif-set dpif_avx512
+    DPIF implementation set to dpif_avx512.
+
+    $ ovs-appctl dpif-netdev/dpif-set dpif_scalar
+    DPIF implementation set to dpif_scalar.
+
+Running Unit Tests with AVX512 DPIF
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Since the AVX512 DPIF is disabled by default, a compile time option is
+available in order to test it with the OVS unit test suite. When building with
+a CPU that supports AVX512, use the following configure option ::
+
+    $ ./configure --enable-dpif-default-avx512
diff --git a/NEWS b/NEWS
index a7bffce97..a03e9d7be 100644
--- a/NEWS
+++ b/NEWS
@@ -2,7 +2,11 @@ Post-v2.15.0
 ---------------------
    - In ovs-vsctl and vtep-ctl, the "find" command now accept new
      operators {in} and {not-in}.
-
+   - Userspace Datapath:
+     * Refactor lib/dpif-netdev.c to multiple header files.
+     * Add avx512 implementation of dpif which can process non recirculated
+       packets. It supports partial HWOL, EMC, SMC and DPCLS lookups.
+     * Add commands to get and set the dpif implementations.
 
 v2.15.0 - xx xxx xxxx
 ---------------------
-- 
2.25.1



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