app/testpmd: support multi-process

[dpdk.git] / doc / guides / testpmd_app_ug / run_app.rst

diff --git a/doc/guides/testpmd_app_ug/run_app.rst b/doc/guides/testpmd_app_ug/run_app.rst
index 37e7c8a..640eade 100644 (file)
--- a/doc/guides/testpmd_app_ug/run_app.rst
+++ b/doc/guides/testpmd_app_ug/run_app.rst
@@ -550,3 +550,87 @@ The command line options are:
        bit 0 - two hairpin ports loop
 
     The default value is 0. Hairpin will use single port mode and implicit Tx flow mode.
+
+
+Testpmd Multi-Process Command-line Options
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The following are the command-line options for testpmd multi-process support:
+
+*   primary process:
+
+.. code-block:: console
+
+    sudo ./dpdk-testpmd -a xxx --proc-type=auto -l 0-1 -- -i --rxq=4 --txq=4 \
+        --num-procs=2 --proc-id=0
+
+*   secondary process:
+
+.. code-block:: console
+
+    sudo ./dpdk-testpmd -a xxx --proc-type=auto -l 2-3 -- -i --rxq=4 --txq=4 \
+        --num-procs=2 --proc-id=1
+
+The command line options are:
+
+*   ``--num-procs=N``
+
+    The number of processes which will be used.
+
+*   ``--proc-id=ID``
+
+    The ID of the current process (ID < num-procs). ID should be different in
+    primary process and secondary process, which starts from '0'.
+
+Calculation rule for queue:
+All queues are allocated to different processes based on ``proc_num`` and
+``proc_id``.
+Calculation rule for the testpmd to allocate queues to each process:
+*   start(queue start id) = proc_id * nb_q / num_procs；
+
+*   end(queue end id) = start + nb_q / num_procs；
+
+For example, if testpmd is configured to have 4 Tx and Rx queues,
+queues 0 and 1 will be used by the primary process and
+queues 2 and 3 will be used by the secondary process.
+
+The number of queues should be a multiple of the number of processes. If not,
+redundant queues will exist after queues are allocated to processes. If RSS
+is enabled, packet loss occurs when traffic is sent to all processes at the same
+time. Some traffic goes to redundant queues and cannot be forwarded.
+
+All the dev ops is supported in primary process. While secondary process is
+not permitted to allocate or release shared memory, so some ops are not supported
+as follows:
+
+- ``dev_configure``
+- ``dev_start``
+- ``dev_stop``
+- ``rx_queue_setup``
+- ``tx_queue_setup``
+- ``rx_queue_release``
+- ``tx_queue_release``
+
+So, any command from testpmd which calls those APIs will not be supported in
+secondary process, like:
+
+.. code-block:: console
+
+    port config all rxq|txq|rxd|txd <value>
+    port config <port_id> rx_offload xxx on/off
+    port config <port_id> tx_offload xxx on/off
+
+etc.
+
+When secondary is running, port in primary is not permitted to be stopped.
+Reconfigure operation is only valid in primary.
+
+Stats is supported, stats will not change when one quits and starts, as they
+share the same buffer to store the stats. Flow rules are maintained in process
+level: primary and secondary has its own flow list (but one flow list in HW).
+The two can see all the queues, so setting the flow rules for the other is OK.
+But in the testpmd primary process receiving or transmitting packets from the
+queue allocated for secondary process is not permitted, and same for secondary
+process.
+
+Flow API and RSS are supported.