On 06/02/18 13:12, Ilya Maximets wrote:
On 05.02.2018 19:29, Eelco Chaudron wrote:
On 02/02/18 17:17, Ilya Maximets wrote:
On 02.02.2018 17:05, Róbert Mulik wrote:
It is possible to change LSC detection mode to polling or interrupt mode
for DPDK interfaces. The default is polling mode. To set interrupt mode,
option dpdk-lsc-interrupt has to be set to true.
In polling mode more processor time is needed, since the OVS repeatedly reads
the link state with a short period. It can lead to packet loss for certain
systems.
In interrupt mode the hardware itself triggers an interrupt when link state
change happens, so less processing time needs for the OVS. It is not possible
to enable the interrupt mode on all hardware.
For detailed description and usage see the dpdk install documentation.
Signed-off-by: Robert Mulik <[email protected]>
Reviewed-by: Ilya Maximets <[email protected]>
8<---- SNIP ---->8
diff --git a/vswitchd/bridge.c b/vswitchd/bridge.c
index f44f950..87608a5 100644
--- a/vswitchd/bridge.c
+++ b/vswitchd/bridge.c
@@ -68,6 +68,9 @@
#include "lib/vswitch-idl.h"
#include "xenserver.h"
#include "vlan-bitmap.h"
+#ifdef DPDK_NETDEV
+#include "./lib/netdev-provider.h"
+#endif
VLOG_DEFINE_THIS_MODULE(bridge);
@@ -601,6 +604,11 @@ bridge_reconfigure(const struct ovsrec_open_vswitch
*ovs_cfg)
ofproto_set_vlan_limit(smap_get_int(&ovs_cfg->other_config, "vlan-limit",
LEGACY_MAX_VLAN_HEADERS));
+#ifdef DPDK_NETDEV
+ netdev_dpdk_set_def_lsc_int_mode_enabled(
+ smap_get_bool(&ovs_cfg->other_config, "dpdk-lsc-interrupt", false));
+#endif
+
I'm still thinking that this is not necessary.
Eelco, why do you think we need to change the default global value in run-time?
IMHO, this only complicates the code. (I didn't check, but it looks like current
implementation will not work anyway.)
I do feel like the global option should be applied directly for the following
reasons:
- There is no way to see what is the running configuration
- If not done this way the LSC mode might change for some devices, for example
if you decide to change another port related configuration.
I feel that we have some kind of misunderstanding.
I'll try to explain my position:
1. I'm not against the global config option. I just want it to be static.
i.e. OVS restart will be required to change it.
Got your point, but why do you want it to be static? I'm arguing against it
as other options, like other_config:pmd-cpu-mask, are also not static.
If it can be done dynamic, I prefer doing it that way.
However if we do go with a static option, it should not effect any existing
NIC configuration, see 4.
2. Per-port option will allow overriding of the global default configuration.
No problem here... However it's not clear to me how we would handle PMDs
not
supporting RTE_ETH_DEV_INTR_LSC?For individual interfaces, we might want to
check this flag, and report an error at configuration time, rather than wait
for re-initialization and add something to the log file, EINVAL?
But how do we deal with the global values and unsupported devices?
Currently
looking at the code it will fail initialization after the restart with no
sensible error message.
3. You're saying that the running configuration is not visible, but It'll be
visible through global default value in other_config and per-port value in
options of the particular interface. If we'll not set any of these configs,
the value will not be visible in any case.
Suggestion: We definitely need to export the current configuration in
netdev_dpdk_get_config(). And it'll be always visible.
I agree we need some way to show the current config because if you set
the global
value (and not restart) you will have no way of knowing the current
operational
state.The best way would be to have some ovs-appctl command to do this,
as logs
might rotate...
Also currently all port settings are on the port, there are no global
defaults.
So people need to be aware that doing an "ovs-vsctl show" does not show
all the
actual port configuration.
Maybe you're saying that we can update global default in database and this
will hide real default value? But it's the default behaviour for many other
'restart required' options like iommu support of vhost_sock_dir.
We need to inform about the global default value in VLOG message while
initializing inside dpdk_init() like it's done for all other options.
Yes, and this makes it some times hard to trouble shoot.
4. I didn't understand your second reason. There is no way to change the current
port by changing config of the another one. DPDK initialized only once, so
default will be fixed on boot and never changed. Any database changes for a
global other_config after the initialization phase will be ignored.
Let me explain, this is with the current implementation if we would have
a global
static option (i.e. v2 of this patch).Assume you configure the following:
ovs-vsctl set Open_vSwitch . other_config:dpdk-lsc-interrupt=true
ovs-vsctl set interface dpdk1 options:n_rxq=2
The last command will trigger a re-configure of dpdk1, and causes now
interrupts
to be enabled.
Just want to indicate its a problem with the patch as implemented, if we
want to
go with a static global configuration it needs to be fixed.
Best regards, Ilya Maximets.
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