path: root/doc
diff options
authorRaslan Darawsheh <>2018-10-18 13:17:29 +0300
committerFerruh Yigit <>2018-10-26 22:14:05 +0200
commitc9aa56edec8ee3d210904c36e145a592a8a56218 (patch)
treea03dfa64fb272127de1062d68a43e2e418a391ec /doc
parented8132e7c91202abfeccc2f9e39c334df2f5db69 (diff)
net/tap: access primary process queues from secondary
In the case the device is created by the primary process, the secondary must request some file descriptors to attach the queues. The file descriptors are shared via IPC Unix socket. Thanks to the IPC synchronization, the secondary process is now able to do Rx/Tx on a TAP created by the primary process. Signed-off-by: Raslan Darawsheh <> Signed-off-by: Thomas Monjalon <> Reviewed-by: Ferruh Yigit <>
Diffstat (limited to 'doc')
2 files changed, 21 insertions, 0 deletions
diff --git a/doc/guides/nics/tap.rst b/doc/guides/nics/tap.rst
index 2714868..9a3d7b3 100644
--- a/doc/guides/nics/tap.rst
+++ b/doc/guides/nics/tap.rst
@@ -152,6 +152,22 @@ Distribute IPv4 TCP packets using RSS to a given MAC address over queues 0-3::
testpmd> flow create 0 priority 4 ingress pattern eth dst is 0a:0b:0c:0d:0e:0f \
/ ipv4 / tcp / end actions rss queues 0 1 2 3 end / end
+Multi-process sharing
+It is possible to attach an existing TAP device in a secondary process,
+by declaring it as a vdev with the same name as in the primary process,
+and without any parameter.
+The port attached in a secondary process will give access to the
+statistics and the queues.
+Therefore it can be used for monitoring or Rx/Tx processing.
+The IPC synchronization of Rx/Tx queues is currently limited:
+ - Maximum 8 queues shared
+ - Synchronized on probing, but not on later port update
diff --git a/doc/guides/rel_notes/release_18_11.rst b/doc/guides/rel_notes/release_18_11.rst
index 9debde7..3fdf171 100644
--- a/doc/guides/rel_notes/release_18_11.rst
+++ b/doc/guides/rel_notes/release_18_11.rst
@@ -146,6 +146,11 @@ New Features
A new devarg ``phy_mac`` was introduced to allow users to use physical
MAC address of the selected PCAP interface.
+* **Added TAP Rx/Tx queues sharing with a secondary process.**
+ A secondary process can attach a TAP device created in the primary process,
+ probe the queues, and process Rx/Tx in a secondary process.
* **Added classification and metering support to SoftNIC PMD.**
Added support for flow classification (rte_flow API), and metering and