netdev-dpdk: Add shared mempool config.

Mempools may currently be shared between DPDK ports based
on port MTU and NUMA. With some hint from the user we can
increase the sharing on MTU and hence reduce memory
consumption in many cases.

For example, a port with MTU 9000, uses a mempool with an
mbuf size based on 9000 MTU. A port with MTU 1500, uses a
different mempool with an mbuf size based on 1500 MTU.

In this case, assuming same NUMA, both these ports could
share the 9000 MTU mempool.

The user must give a hint as order of creation of ports and
setting of MTUs may vary and we need to ensure that upgrades
from older OVS versions do not require more memory.

This scheme can also prevent multiple mempools being created
for cases where a port is added picking up a default MTU and
an appropriate mempool, but later has it's MTU changed to a
different value requiring a different mempool.

Example usage:

 $ ovs-vsctl --no-wait set Open_vSwitch . \
   other_config:shared-mempool-config=9000,1500:1,6000:1

Port added on NUMA 0:
* MTU 1500, use mempool based on 9000 MTU
* MTU 5000, use mempool based on 9000 MTU
* MTU 9000, use mempool based on 9000 MTU
* MTU 9300, use mempool based on 9300 MTU (existing behaviour)

Port added on NUMA 1:
* MTU 1500, use mempool based on 1500 MTU
* MTU 5000, use mempool based on 6000 MTU
* MTU 9000, use mempool based on 9000 MTU
* MTU 9300, use mempool based on 9300 MTU (existing behaviour)

Default behaviour is unchanged and mempools are still only created
when needed.

Signed-off-by: Kevin Traynor <ktraynor@redhat.com>
Reviewed-by: David Marchand <david.marchand@redhat.com>
Acked-by: Sunil Pai G <sunil.pai.g@intel.com>
Signed-off-by: Ian Stokes <ian.stokes@intel.com>

1 files changed, 37 insertions, 0 deletions

diff --git a/vswitchd/vswitch.xml b/vswitchd/vswitch.xml
index cc1dd77ec..98486c009 100644
--- a/vswitchd/vswitch.xml
+++ b/vswitchd/vswitch.xml
@@ -490,6 +490,43 @@
         </p>
       </column>
 
+      <column name="other_config" key="shared-mempool-config">
+              <p>Specifies dpdk shared mempool config.</p>
+              <p>Value should be set in the following form:</p>
+              <p>
+                <code>other_config:shared-mempool-config=&lt;
+                  user-shared-mempool-mtu-list&gt;</code>
+              </p>
+              <p>where</p>
+              <p>
+                <ul>
+                  <li>
+                    &lt;user-shared-mempool-mtu-list&gt; ::=
+                    NULL | &lt;non-empty-list&gt;
+                  </li>
+                  <li>
+                    &lt;non-empty-list&gt; ::= &lt;user-mtus&gt; |
+                                               &lt;user-mtus&gt; ,
+                                               &lt;non-empty-list&gt;
+                  </li>
+                  <li>
+                    &lt;user-mtus&gt; ::= &lt;mtu-all-socket&gt; |
+                                          &lt;mtu-socket-pair&gt;
+                  </li>
+                  <li>
+                    &lt;mtu-all-socket&gt; ::= &lt;mtu&gt;
+                  </li>
+                  <li>
+                    &lt;mtu-socket-pair&gt; ::= &lt;mtu&gt; : &lt;socket-id&gt;
+                  </li>
+                </ul>
+              </p>
+        <p>
+          Changing this value requires restarting the daemon if dpdk-init has
+          already been set to true.
+        </p>
+      </column>
+
       <column name="other_config" key="tx-flush-interval"
               type='{"type": "integer",
                      "minInteger": 0, "maxInteger": 1000000}'>