| Message ID | 1491222467-13040-1-git-send-email-przemyslawx.lal@intel.com |
|---|---|
| State | Accepted |
| Delegated to: | Darrell Ball |
| Headers | show |
On 4/3/17, 5:27 AM, "ovs-dev-bounces@openvswitch.org on behalf of Przemyslaw Lal" <ovs-dev-bounces@openvswitch.org on behalf of przemyslawx.lal@intel.com> wrote:
In current implementation port_id is used as an ifindex for all netdev-dpdk
interfaces.
For physical DPDK interfaces using port_id as ifindex causes that '0' is set as
ifindex for 'dpdk0' interface, '1' for 'dpdk1' and so on. For the DPDK vHost
interfaces ifindexes are not even assigned (0 is used by default) due to the
fact that vHost ports don't use port_id field from the DPDK library.
This causes multiple negative side-effects. First of all 0 is an invalid
ifindex value. The other issue is possible overlapping of 'dpdkX' interfaces
ifindex values with the ifindexes of kernel space interfaces which may cause
problems in any external tools that use those values. Neither 'dpdk0', nor any
DPDK vHost interfaces are visible in sFlow collector tools, as all interfaces
with ifindexes smaller than 1 are ignored.
Proposed solution to these issues is to calculate a hash of interface's name
and use calculated value as an ifindex. This way interfaces keep their
ifindexes during OVS-DPDK restarts, ports re-initialization events, etc., show
up in sFlow collectors and meet RFC 2863 specification regarding re-using
ifindex values by the same virtual interfaces and maximum ifindex value.
Signed-off-by: Przemyslaw Lal <przemyslawx.lal@intel.com>
---
lib/netdev-dpdk.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c
index ddc651b..687b0a5 100644
--- a/lib/netdev-dpdk.c
+++ b/lib/netdev-dpdk.c
@@ -2215,7 +2215,11 @@ netdev_dpdk_get_ifindex(const struct netdev *netdev)
int ifindex;
ovs_mutex_lock(&dev->mutex);
- ifindex = dev->port_id;
+ /* Calculate hash from the netdev name. Ensure that ifindex is a 24-bit
+ * postive integer to meet RFC 2863 recommendations.
+ */
+ uint32_t h = hash_string(netdev->name, 0);
+ ifindex = (int)(h % 0xfffffe + 1);
If user configuration was supported, enforcing uniqueness would be the
responsibility of the user.
One minor question:
I know other ifindex implementations do not limit to 24 bits, so I checked RFC 2863.
What section is the 24 bit limit recommendation mentioned in RFC 2863; I missed it.
ovs_mutex_unlock(&dev->mutex);
return ifindex;
--
1.9.1
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On 04/04/2017 06:14, Darrell Ball wrote: > > On 4/3/17, 5:27 AM, "ovs-dev-bounces@openvswitch.org on behalf of Przemyslaw Lal" <ovs-dev-bounces@openvswitch.org on behalf of przemyslawx.lal@intel.com> wrote: > > In current implementation port_id is used as an ifindex for all netdev-dpdk > interfaces. > > For physical DPDK interfaces using port_id as ifindex causes that '0' is set as > ifindex for 'dpdk0' interface, '1' for 'dpdk1' and so on. For the DPDK vHost > interfaces ifindexes are not even assigned (0 is used by default) due to the > fact that vHost ports don't use port_id field from the DPDK library. > > This causes multiple negative side-effects. First of all 0 is an invalid > ifindex value. The other issue is possible overlapping of 'dpdkX' interfaces > ifindex values with the ifindexes of kernel space interfaces which may cause > problems in any external tools that use those values. Neither 'dpdk0', nor any > DPDK vHost interfaces are visible in sFlow collector tools, as all interfaces > with ifindexes smaller than 1 are ignored. > > Proposed solution to these issues is to calculate a hash of interface's name > and use calculated value as an ifindex. This way interfaces keep their > ifindexes during OVS-DPDK restarts, ports re-initialization events, etc., show > up in sFlow collectors and meet RFC 2863 specification regarding re-using > ifindex values by the same virtual interfaces and maximum ifindex value. > > Signed-off-by: Przemyslaw Lal <przemyslawx.lal@intel.com> > --- > lib/netdev-dpdk.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c > index ddc651b..687b0a5 100644 > --- a/lib/netdev-dpdk.c > +++ b/lib/netdev-dpdk.c > @@ -2215,7 +2215,11 @@ netdev_dpdk_get_ifindex(const struct netdev *netdev) > int ifindex; > > ovs_mutex_lock(&dev->mutex); > - ifindex = dev->port_id; > + /* Calculate hash from the netdev name. Ensure that ifindex is a 24-bit > + * postive integer to meet RFC 2863 recommendations. > + */ > + uint32_t h = hash_string(netdev->name, 0); > + ifindex = (int)(h % 0xfffffe + 1); > > > If user configuration was supported, enforcing uniqueness would be the > responsibility of the user. This was already discussed on this mailing list and outcome was that while hash is not perfect, it is the best solution for now. Also please keep in mind that names of the physical DPDK devices and dpdkvhostuser interfaces are configurable, so user can still enforce uniqueness. > > One minor question: > I know other ifindex implementations do not limit to 24 bits, so I checked RFC 2863. > What section is the 24 bit limit recommendation mentioned in RFC 2863; I missed it. Recommendation of RFC 2863 is to use "small integers". Main purpose of this patch is to enable dpdkvhostuser interfaces in sFlow metrics collecting tools. After posting previous version I've received feedback from the community that not all interfaces are visible in sFlow collectors and maximum supported ifindex is 2^24. Here's the sFlow v5 specification: http://sflow.org/sflow_version_5.txt > > > > ovs_mutex_unlock(&dev->mutex); > > return ifindex; > -- > 1.9.1 > > _______________________________________________ > dev mailing list > dev@openvswitch.org > https://urldefense.proofpoint.com/v2/url?u=https-3A__mail.openvswitch.org_mailman_listinfo_ovs-2Ddev&d=DwICAg&c=uilaK90D4TOVoH58JNXRgQ&r=BVhFA09CGX7JQ5Ih-uZnsw&m=Rcpenle5jqQ1mu3STwFMODvsTFjKL9iMBrwMfu9J8FM&s=FJtoKpLo8NxpzHwFKSz6xsT3aGqZCiR507-MDVxjFeE&e= > > > >
On 4/4/17, 3:09 AM, "Lal, PrzemyslawX" <przemyslawx.lal@intel.com> wrote:
On 04/04/2017 06:14, Darrell Ball wrote:
>
> On 4/3/17, 5:27 AM, "ovs-dev-bounces@openvswitch.org on behalf of Przemyslaw Lal" <ovs-dev-bounces@openvswitch.org on behalf of przemyslawx.lal@intel.com> wrote:
>
> In current implementation port_id is used as an ifindex for all netdev-dpdk
> interfaces.
>
> For physical DPDK interfaces using port_id as ifindex causes that '0' is set as
> ifindex for 'dpdk0' interface, '1' for 'dpdk1' and so on. For the DPDK vHost
> interfaces ifindexes are not even assigned (0 is used by default) due to the
> fact that vHost ports don't use port_id field from the DPDK library.
>
> This causes multiple negative side-effects. First of all 0 is an invalid
> ifindex value. The other issue is possible overlapping of 'dpdkX' interfaces
> ifindex values with the ifindexes of kernel space interfaces which may cause
> problems in any external tools that use those values. Neither 'dpdk0', nor any
> DPDK vHost interfaces are visible in sFlow collector tools, as all interfaces
> with ifindexes smaller than 1 are ignored.
>
> Proposed solution to these issues is to calculate a hash of interface's name
> and use calculated value as an ifindex. This way interfaces keep their
> ifindexes during OVS-DPDK restarts, ports re-initialization events, etc., show
> up in sFlow collectors and meet RFC 2863 specification regarding re-using
> ifindex values by the same virtual interfaces and maximum ifindex value.
>
> Signed-off-by: Przemyslaw Lal <przemyslawx.lal@intel.com>
> ---
> lib/netdev-dpdk.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c
> index ddc651b..687b0a5 100644
> --- a/lib/netdev-dpdk.c
> +++ b/lib/netdev-dpdk.c
> @@ -2215,7 +2215,11 @@ netdev_dpdk_get_ifindex(const struct netdev *netdev)
> int ifindex;
>
> ovs_mutex_lock(&dev->mutex);
> - ifindex = dev->port_id;
> + /* Calculate hash from the netdev name. Ensure that ifindex is a 24-bit
> + * postive integer to meet RFC 2863 recommendations.
> + */
> + uint32_t h = hash_string(netdev->name, 0);
> + ifindex = (int)(h % 0xfffffe + 1);
>
>
> If user configuration was supported, enforcing uniqueness would be the
> responsibility of the user.
This was already discussed on this mailing list and outcome was that while hash is not perfect, it is the best solution for now.
Also, please keep in mind that names of the physical DPDK devices and dpdkvhostuser interfaces are configurable, so user can still enforce
uniqueness.
I know uniqueness could be enforced by trial and error of name selection.
I saw the comment
“At some point, with vhost-pmd we will have port_ids also for vhost interfaces.
Maybe we can revisit this approach when that becomes available.”
If others are fine, then so am I.
>
> One minor question:
> I know other ifindex implementations do not limit to 24 bits, so I checked RFC 2863.
> What section is the 24 bit limit recommendation mentioned in RFC 2863; I missed it.
Recommendation of RFC 2863 is to use "small integers". Main purpose of this patch is to enable dpdkvhostuser interfaces in sFlow metrics collecting tools.
After posting previous version I've received feedback from the community that not all interfaces are visible in sFlow collectors and maximum supported ifindex is 2^24.
Here's the sFlow v5 specification: https://urldefense.proofpoint.com/v2/url?u=http-3A__sflow.org_sflow-5Fversion-5F5.txt&d=DwICaQ&c=uilaK90D4TOVoH58JNXRgQ&r=BVhFA09CGX7JQ5Ih-uZnsw&m=BU2KdxyVIZVbS8qF48IH8n4FNs8DBkSQf7Bp0zdQvXE&s=ZgBDm95VkGw_R6_ULUFT5mh0OtbGPzcnjpWXze9DIGw&e=
2^24 is an sflow recommendation (rather than Interfaces MIB recommendation)
– that’s fine; I was just curious where it came from.
>
>
>
> ovs_mutex_unlock(&dev->mutex);
>
> return ifindex;
> --
> 1.9.1
>
> _______________________________________________
> dev mailing list
> dev@openvswitch.org
> https://urldefense.proofpoint.com/v2/url?u=https-3A__mail.openvswitch.org_mailman_listinfo_ovs-2Ddev&d=DwICAg&c=uilaK90D4TOVoH58JNXRgQ&r=BVhFA09CGX7JQ5Ih-uZnsw&m=Rcpenle5jqQ1mu3STwFMODvsTFjKL9iMBrwMfu9J8FM&s=FJtoKpLo8NxpzHwFKSz6xsT3aGqZCiR507-MDVxjFeE&e=
>
>
>
>
On 4/4/17, 5:47 PM, "Darrell Ball" <dball@vmware.com> wrote:
On 4/4/17, 3:09 AM, "Lal, PrzemyslawX" <przemyslawx.lal@intel.com> wrote:
On 04/04/2017 06:14, Darrell Ball wrote:
>
> On 4/3/17, 5:27 AM, "ovs-dev-bounces@openvswitch.org on behalf of Przemyslaw Lal" <ovs-dev-bounces@openvswitch.org on behalf of przemyslawx.lal@intel.com> wrote:
>
> In current implementation port_id is used as an ifindex for all netdev-dpdk
> interfaces.
>
> For physical DPDK interfaces using port_id as ifindex causes that '0' is set as
> ifindex for 'dpdk0' interface, '1' for 'dpdk1' and so on. For the DPDK vHost
> interfaces ifindexes are not even assigned (0 is used by default) due to the
> fact that vHost ports don't use port_id field from the DPDK library.
>
> This causes multiple negative side-effects. First of all 0 is an invalid
> ifindex value. The other issue is possible overlapping of 'dpdkX' interfaces
> ifindex values with the ifindexes of kernel space interfaces which may cause
> problems in any external tools that use those values. Neither 'dpdk0', nor any
> DPDK vHost interfaces are visible in sFlow collector tools, as all interfaces
> with ifindexes smaller than 1 are ignored.
>
> Proposed solution to these issues is to calculate a hash of interface's name
> and use calculated value as an ifindex. This way interfaces keep their
> ifindexes during OVS-DPDK restarts, ports re-initialization events, etc., show
> up in sFlow collectors and meet RFC 2863 specification regarding re-using
> ifindex values by the same virtual interfaces and maximum ifindex value.
>
> Signed-off-by: Przemyslaw Lal <przemyslawx.lal@intel.com>
> ---
> lib/netdev-dpdk.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c
> index ddc651b..687b0a5 100644
> --- a/lib/netdev-dpdk.c
> +++ b/lib/netdev-dpdk.c
> @@ -2215,7 +2215,11 @@ netdev_dpdk_get_ifindex(const struct netdev *netdev)
> int ifindex;
>
> ovs_mutex_lock(&dev->mutex);
> - ifindex = dev->port_id;
> + /* Calculate hash from the netdev name. Ensure that ifindex is a 24-bit
> + * postive integer to meet RFC 2863 recommendations.
> + */
> + uint32_t h = hash_string(netdev->name, 0);
> + ifindex = (int)(h % 0xfffffe + 1);
>
>
> If user configuration was supported, enforcing uniqueness would be the
> responsibility of the user.
This was already discussed on this mailing list and outcome was that while hash is not perfect, it is the best solution for now.
Also, please keep in mind that names of the physical DPDK devices and dpdkvhostuser interfaces are configurable, so user can still enforce
uniqueness.
I know uniqueness could be enforced by trial and error of name selection.
I saw the comment
“At some point, with vhost-pmd we will have port_ids also for vhost interfaces.
Maybe we can revisit this approach when that becomes available.”
If others are fine, then so am I.
The uniqueness issue is understood and there is a workaround capability to
address it.
Let us just fold the patch in, since the patch has been out for long enough to
receive feedback.
Acked by: Darrell Ball <dlu998@gmail.com>
>
> One minor question:
> I know other ifindex implementations do not limit to 24 bits, so I checked RFC 2863.
> What section is the 24 bit limit recommendation mentioned in RFC 2863; I missed it.
Recommendation of RFC 2863 is to use "small integers". Main purpose of this patch is to enable dpdkvhostuser interfaces in sFlow metrics collecting tools.
After posting previous version I've received feedback from the community that not all interfaces are visible in sFlow collectors and maximum supported ifindex is 2^24.
Here's the sFlow v5 specification: https://urldefense.proofpoint.com/v2/url?u=http-3A__sflow.org_sflow-5Fversion-5F5.txt&d=DwICaQ&c=uilaK90D4TOVoH58JNXRgQ&r=BVhFA09CGX7JQ5Ih-uZnsw&m=BU2KdxyVIZVbS8qF48IH8n4FNs8DBkSQf7Bp0zdQvXE&s=ZgBDm95VkGw_R6_ULUFT5mh0OtbGPzcnjpWXze9DIGw&e=
2^24 is an sflow recommendation (rather than Interfaces MIB recommendation)
– that’s fine; I was just curious where it came from.
>
>
>
> ovs_mutex_unlock(&dev->mutex);
>
> return ifindex;
> --
> 1.9.1
>
> _______________________________________________
> dev mailing list
> dev@openvswitch.org
> https://urldefense.proofpoint.com/v2/url?u=https-3A__mail.openvswitch.org_mailman_listinfo_ovs-2Ddev&d=DwICAg&c=uilaK90D4TOVoH58JNXRgQ&r=BVhFA09CGX7JQ5Ih-uZnsw&m=Rcpenle5jqQ1mu3STwFMODvsTFjKL9iMBrwMfu9J8FM&s=FJtoKpLo8NxpzHwFKSz6xsT3aGqZCiR507-MDVxjFeE&e=
>
>
>
>
diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c index ddc651b..687b0a5 100644 --- a/lib/netdev-dpdk.c +++ b/lib/netdev-dpdk.c @@ -2215,7 +2215,11 @@ netdev_dpdk_get_ifindex(const struct netdev *netdev) int ifindex; ovs_mutex_lock(&dev->mutex); - ifindex = dev->port_id; + /* Calculate hash from the netdev name. Ensure that ifindex is a 24-bit + * postive integer to meet RFC 2863 recommendations. + */ + uint32_t h = hash_string(netdev->name, 0); + ifindex = (int)(h % 0xfffffe + 1); ovs_mutex_unlock(&dev->mutex); return ifindex;
In current implementation port_id is used as an ifindex for all netdev-dpdk interfaces. For physical DPDK interfaces using port_id as ifindex causes that '0' is set as ifindex for 'dpdk0' interface, '1' for 'dpdk1' and so on. For the DPDK vHost interfaces ifindexes are not even assigned (0 is used by default) due to the fact that vHost ports don't use port_id field from the DPDK library. This causes multiple negative side-effects. First of all 0 is an invalid ifindex value. The other issue is possible overlapping of 'dpdkX' interfaces ifindex values with the ifindexes of kernel space interfaces which may cause problems in any external tools that use those values. Neither 'dpdk0', nor any DPDK vHost interfaces are visible in sFlow collector tools, as all interfaces with ifindexes smaller than 1 are ignored. Proposed solution to these issues is to calculate a hash of interface's name and use calculated value as an ifindex. This way interfaces keep their ifindexes during OVS-DPDK restarts, ports re-initialization events, etc., show up in sFlow collectors and meet RFC 2863 specification regarding re-using ifindex values by the same virtual interfaces and maximum ifindex value. Signed-off-by: Przemyslaw Lal <przemyslawx.lal@intel.com> --- lib/netdev-dpdk.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)