@@ -33,15 +33,16 @@ Thread mode
This mode is automatically selected when the port's ``tx-steering`` option is
set to ``thread`` or unset.
-Depending on the port's number of Tx queues being greater or equal than the
-number of PMD threads, static txq mapping or XPS will be used.
+Thread mode enables static (1:1) thread-to-txq mapping when the number of Tx
+queues is greater than number of PMD threads, and dynamic (N:1) mapping if
+equal or lower. In this mode a single thread can not use more than 1 transmit
+queue of a given port.
This is the recommended mode for performance reasons if the number of Tx queues
-is greater or equal to the number of PMD threads, because the Tx lock is not
-acquired.
+is greater than the number of PMD threads, because the Tx lock is not acquired.
-If the number of Tx queues is greater than the number of threads, the remaining
-Tx queues will not be used.
+If the number of Tx queues is greater than the number of threads (including the
+main thread), the remaining Tx queues will not be used.
This mode is enabled by default.
This patch fixes the thread mode part, as the static thread-to-txq mapping selection depends on whether the number of queues is strictly greater than the number of PMD threads, and anot greater or equal. The section is also reworded as per Ilya's suggestion. Fixes: c18e707b2f25 ("dpif-netdev: Introduce hash-based Tx packet steering mode.") Reported-by: Kevin Traynor <ktraynor@redhat.com> Reported-by: Ilya Maximets <i.maximets@ovn.org> Acked-by: Kevin Traynor <ktraynor@redhat.com> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com> --- Documentation/topics/userspace-tx-steering.rst | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-)