On 1/23/2017 8:41 PM, Joe Stringer wrote:
On 22 January 2017 at 08:13, Paul Blakey <[email protected]> wrote:
On 05/01/2017 03:26, Joe Stringer wrote:
On 25 December 2016 at 03:39, Paul Blakey <[email protected]> wrote:
Add a new configuration option - hw-offload that enables netdev
flow api. Enabling this option will allow offloading flows
using netdev implementation instead of the kernel datapath.
This configuration option defaults to false - disabled.
Signed-off-by: Paul Blakey <[email protected]>
Reviewed-by: Roi Dayan <[email protected]>
---
lib/netdev.c | 18 ++++++++++++++++++
lib/netdev.h | 2 ++
vswitchd/bridge.c | 2 ++
vswitchd/vswitch.xml | 11 +++++++++++
4 files changed, 33 insertions(+)
diff --git a/lib/netdev.c b/lib/netdev.c
index 3ac3c48..b289166 100644
--- a/lib/netdev.c
+++ b/lib/netdev.c
@@ -2071,7 +2071,25 @@ netdev_init_flow_api(struct netdev *netdev)
{
const struct netdev_class *class = netdev->netdev_class;
+ if (!netdev_flow_api_enabled) {
+ return EOPNOTSUPP;
+ }
+
return (class->init_flow_api
? class->init_flow_api(netdev)
: EOPNOTSUPP);
}
+
+bool netdev_flow_api_enabled = false;
+
+void
+netdev_set_flow_api_enabled(bool enabled)
+{
+ static struct ovsthread_once once = OVSTHREAD_ONCE_INITIALIZER;
+
+ if (ovsthread_once_start(&once)) {
+ netdev_flow_api_enabled = enabled;
+ VLOG_INFO("netdev: Flow API %s", enabled ? "Enabled" :
"Disabled");
+ ovsthread_once_done(&once);
+ }
+}
Requiring restart to apply this option seems a bit arbitrary, why not
allow it to be changed at runtime?
Because it isn't something that is supposed to change often,
It might cause problems if its enabled later on with different (netdev)
implementations. We can try and test changing it to runtime at a later time.
Forcing the user to restart OVS to make a database setting take effect
is an unusual requirement. Even uncommon configurations that require
datapath-level changes (eg, reconfiguring queues) is applied in OVS
without requiring the user to intervene and restart. I understand that
even DPDK init doesn't require restart any more.
Here's another question: Let's say that hardware offloads is enabled
and traffic runs. User turns it off, restarts OVS. What happens to the
hardware flows? Presumably OVS doesn't manage them any more because
hw-offloads is off, but they would continue to forward traffic. If OVS
then gets different OpenFlow rules then the forwarding could be wrong.
Hi Joe,
We understand that forcing the user to restart OVS is not something
common we want to do.
We can make this option changeable at runtime and flush all the rules
when hw-offload changes from true to false.
If something will block us we'll let you know and if a future
requirement will need this then it can be changed later.
To answer your next question then this is also what happens now when the
user restarts OVS. All rules are flushed so there shoudn't be HW
forwarding rules.
Thanks,
Roi
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