On 1/20/22 14:20, Kevin Traynor wrote:
On 20/01/2022 12:16, Ilya Maximets wrote:
On 1/18/22 11:51, Kevin Traynor wrote:
On 17/01/2022 22:25, Maxime Coquelin wrote:
This patch documents PMD's other_config:tx-steering option.
Signed-off-by: Maxime Coquelin <maxime.coque...@redhat.com>
---
vswitchd/vswitch.xml | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)
diff --git a/vswitchd/vswitch.xml b/vswitchd/vswitch.xml
index 026b5e2ca..ef7f8f2c8 100644
--- a/vswitchd/vswitch.xml
+++ b/vswitchd/vswitch.xml
@@ -3375,6 +3375,28 @@ ovs-vsctl add-port br0 p0 -- set Interface p0
type=patch options:peer=p1 \
</ul>
<p>This option may only be used with dpdk VF
representors.</p>
</column>
+
+ <column name="other_config" key="tx-steering"
+ type='{"type": "string",
+ "enum": ["set", ["thread", "hash"]]}'>
+ <p>
+ Specifies the Tx steering mode for the interface.
+ </p>
+ <p>
+ <code>thread</code> enables static txq mapping when the
number of txq
+ is greater or equal than the number of PMD threads, and
XPS mode if
+ lower than the number of PMD threads.
I think it should be 'greater than PMD threads, and XPS mode if equal
or lower
than the number of PMD threads.', because one txq is also needed for
the OVS
main thread. I checked the code and this txq is accounted for in
wanted_txqs.
I would also recommend to not use the 'XPS' as a name for the dynamic
txq mapping
in the 'thread' mode. Because all of this is a sort of XPS. The hash
mode is
a form of {trans,x}mit packet steering too.
So, something like this maybe:
<code>thread</code> 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.
And, I think, we need to fix the userspace-tx-steering.rst too, e.g.:
Depending on the port's number of Tx queues being greater or equal
than the
number of PMD threads, static (1:1) or dynamic (N:1) thread-to-txq
mapping
will be used.
Maxime, Kevin, what do you think?
+1. Only thing I'd add is to explicitly associate each mode with the
txq/PMD values in the rst, like it is done in the xml.
Agree, I'm changing the paragraph to:
"
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 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
(including the
main thread), the remaining Tx queues will not be used.
"
Sounds good to you?
Thanks,
Maxime
With this fix:
Acked-by: Kevin Traynor <ktray...@redhat.com>
+ </p>
+ <p>
+ <code>hash</code> enables hash-based Tx steering, which
distributes
+ the packets on all the transmit queues based on their
5-tuples
+ hashes.
+ </p>
+ <p>
+ Defaults to <code>thread</code>.
+ </p>
+ </column>
+
</group>
<group title="EMC (Exact Match Cache) Configuration">
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