Re: [ovs-discuss] EMC lookup disabled but still there some processing going on with emc lookup

[O Mahony, Billy]

Are you setting emc-insert-inv-prob in the ovsdb before OvS starts?

There should not be any packets being processed before the configuration is 
applied but if you remove the early startup time until you are sure the system 
is in a steady state from the analysis do you still see time being spend in 
emc_lookup and emc_insert?

Are you sure that the debug info (.exe) available to vtune when it is analyzing 
is identical to the one that was used to gather the stats? Otherwise an address 
could be attributed to the wrong symbol.

/Billy.

From: ovs-discuss-boun...@openvswitch.org 
[mailto:ovs-discuss-boun...@openvswitch.org] On Behalf Of Krish
Sent: Thursday, March 22, 2018 3:48 AM
To: ovs-discuss@openvswitch.org
Subject: [ovs-discuss] EMC lookup disabled but still there some processing 
going on with emc lookup

Hello everyone

I am testing ovs-vswitch caches time spent using intel vtune.

I disabled emc lookup using "emc-insert-inv-prob=0" but still I can see emc 
lookup is not disabled and also there is insertion which takes place into emc 
also after the packet completes fast-path processing.

I am attaching the screenshots on Intel vtune along with this mail.

Can anyone please explain why this happened?

Thank you

Regards


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[ovs-discuss] Extending the same network across datacenters

[Roberto Suárez Soto]

Hi,

    I've just known about OVS, so please bear with me if I'm asking
something silly or already in the FAQs. Don't hesitate to RTFM me if
that's the case.

    We have a main datacenter and a backup one (for disaster recovery),
and would like to be able to start VMs in any of them without changing
IP addresses. For example: let's say I have a VM with IP 10.0.0.10 in
the main datacenter, and for whatever reason, I have to move it to the
backup one. I'd like it to be moved with the same IP, so we needn't
change DNS entries, and have users access it without notice.

    Communication between main and backup datacenters would be done via
a dedicated link, with Linux firewalls at both ends, and users would
have to pass through those firewalls to access the VMs. The firewalls
would have physical interfaces connecting them to the VM network, the
user network and the dedicated network that links the two datacenters.
Ideally, when a user wants to get to some VM, traffic would go to one of
the firewalls and it would magically know how to reach it, be it in the
main or the backup datacenter.

    I think this could be done with something in the firewalls that
bridged together the physical interface and the dedicated link, and
that's where OVS comes in. Could it be used to do this?

    Sorry for sucking at explaining myself. Please, feel free to ask
whatever I didn't make clear enough.

    Thanks in advance,

-- 
Roberto Suárez Soto
Allenta Consulting  (+34 881 922 600)
ISO 9001, ISO 14001, ISO 27001, EMAS 
Privacidad / Privacy 
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Re: [ovs-discuss] Setting TCP rwnd value in Open vSwitch

[Taimur Hafeez]

 I applied the patch but it I am unable to do it properly. For this reason,
i am sharing environment on which i tried along with the terminal output.
Also i tried various other commands of patching but unfortunately all in
vain. Could you please what version of OVS and ubuntu you used for this
patch? Please guide through this. Thankyou!

Environment 1:

OVS version 2.3.90
Linux sdnhubvm  4.4.0-97-generic #120-14.04.1-Ubuntu SMP

Environment 2:
OVS version 2.8.1
Linux ubuntu ibm  4.13.0-36-generic #40- Ubuntu SMP


**My comment==Environment 1 Ubuntu terminal
log*
ubuntu@sdnhubvm:~/openvswitch$ patch -t <  tcp_rwnd.diff
can't find file to patch at input line 5
Perhaps you should have used the -p or --strip option?
The text leading up to this was:
--
|diff --git a/datapath/linux/compat/include/linux/openvswitch.h
b/datapath/linux/compat/include/linux/openvswitch.h
|index 12260d8..dd84b04 100644
|--- a/datapath/linux/compat/include/linux/openvswitch.h
|+++ b/datapath/linux/compat/include/linux/openvswitch.h
--
No file to patch.  Skipping patch.
2 out of 2 hunks ignored
can't find file to patch at input line 33
Perhaps you should have used the -p or --strip option?
The text leading up to this was:
--
|diff --git a/include/openvswitch/flow.h b/include/openvswitch/flow.h
|index df80dfe..64da205 100644
|--- a/include/openvswitch/flow.h
|+++ b/include/openvswitch/flow.h
--
No file to patch.  Skipping patch.
2 out of 2 hunks ignored
can't find file to patch at input line 57
Perhaps you should have used the -p or --strip option?
The text leading up to this was:
--
|diff --git a/include/openvswitch/ofp-actions.h b/include/openvswitch/ofp-
actions.h
|index 74e9dcc..a7512e5 100644
|--- a/include/openvswitch/ofp-actions.h
|+++ b/include/openvswitch/ofp-actions.h
--
No file to patch.  Skipping patch.
2 out of 2 hunks ignored
can't find file to patch at input line 87
Perhaps you should have used the -p or --strip option?
The text leading up to this was:
--
|diff --git a/lib/odp-execute.c b/lib/odp-execute.c
|index 65a6fcd..b052f1c 100644
|--- a/lib/odp-execute.c
|+++ b/lib/odp-execute.c
--
No file to patch.  Skipping patch.
2 out of 2 hunks ignored
can't find file to patch at input line 122
Perhaps you should have used the -p or --strip option?
The text leading up to this was:
--
|diff --git a/lib/odp-util.c b/lib/odp-util.c
|index 626a82c..a124d6e 100644
|--- a/lib/odp-util.c
|+++ b/lib/odp-util.c
--
No file to patch.  Skipping patch.
patch:  malformed patch at line 192:  {


-


On Fri, Mar 23, 2018 at 5:07 PM, Taimur Hafeez 
wrote:

> I applied the patch but it I am unable to do it properly. For this reason,
> i am sharing environment on which i tried along with the terminal output.
> Also i tried various other commands of patching but unfortunately all in
> vain. Could you please what version of OVS and ubuntu you used for this
> patch? Please guide through this. Thankyou!
>
> Environment 1:
>
> OVS version 2.3.90
> Linux sdnhubvm  4.4.0-97-generic #120-14.04.1-Ubuntu SMP
>
> Environment 2:
> OVS version 2.8.1
> Linux ubuntu ibm  4.13.0-36-generic #40- Ubuntu SMP
>
>
> **My comment==Environment 1 Ubuntu terminal
> log*
> ubuntu@sdnhubvm:~/openvswitch$ patch -t <  tcp_rwnd.diff
> can't find file to patch at input line 5
> Perhaps you should have used the -p or --strip option?
> The text leading up to this was:
> --
> |diff --git a/datapath/linux/compat/include/linux/openvswitch.h
> b/datapath/linux/compat/include/linux/openvswitch.h
> |index 12260d8..dd84b04 100644
> |--- a/datapath/linux/compat/include/linux/openvswitch.h
> |+++ b/datapath/linux/compat/include/linux/openvswitch.h
> --
> No file to patch.  Skipping patch.
> 2 out of 2 hunks ignored
> can't find file to patch at input line 33
> Perhaps you should have used the -p or --strip option?
> The text leading up to this was:
> --
> |diff --git a/include/openvswitch/flow.h b/include/openvswitch/flow.h
> |index df80dfe..64da205 100644
> |--- a/include/openvswitch/flow.h
> |+++ b/include/openvswitch/flow.h
> --
> No file to patch.  Skipping patch.
> 2 out of 2 hunks ignored
> can't find file to patch at input line 57
> Perhaps you should have used the -p or --strip option?
> The text leading up to this was:
> --
> |diff --git a/include/openvswitch/ofp-actions.h b/include/openvswitch/ofp-
> actions.h
> |index 74e9dcc..a7512e5 100644
> |--- a/include/openvswitch/ofp-actions.h
> |+++ b/include/openvswitch/ofp-actions.h
> --
> No file to patch.  Skipping patch.
> 2 

Re: [ovs-discuss] Way to get average time spent

[O Mahony, Billy]

Hi Krish,

You will need to compile with debug info and also with in-lining turned off. 
Many functions get in-lined and in that case the perf report cannot attribute 
time to the in-lined function but only to the caller. Obviously performance 
overall drops in that case but the relative cost of each function should not be 
affected.

You should also checkout Brendan Gregg’s flame graphs 
http://www.brendangregg.com/flamegraphs.html as a visualization of cpu cost.

If you are using dpdk-ovs then you should pin the PMD to an isolated core and 
use perf to sample the call stack on that core only. Details of pinning & 
isolation are in the dpdk sections of the ovs documentation.

I have not run perf on kernel OvS. That would be a matter of using the correct 
flags to sample by kernel module or thread.

You will need to be reasonably familiar with the code in order to interpret the 
results. These are some blog posts on the EMC and netdev datapath classifier 
for OvS-DPDK :
https://software.intel.com/en-us/articles/the-open-vswitch-exact-match-cache
https://software.intel.com/en-us/articles/ovs-dpdk-datapath-classifier

Again for OvS-DPDK you could also use the output from ovs-appctl 
dpcls/pmd-stats-show. By using a very small number of flows you can ensure that 
your traffic his hitting the EMC and you can measure the EMC lookup cost. Then 
you can disable the EMC (using emc-insert-inv-prob setting) and measure the 
classifier lookup cost. Be aware those cost include the rx and tx costs which 
actually decrease as traffic increases – as the packet batch size increases 
leadings to lower per-packet tx/rx cost.

Regards,
Billy.

From: ovs-discuss-boun...@openvswitch.org 
[mailto:ovs-discuss-boun...@openvswitch.org] On Behalf Of Krish
Sent: Thursday, March 15, 2018 2:52 AM
To: Justin Pettit ; Greg Rose ; 
ovs-discuss@openvswitch.org
Subject: Re: [ovs-discuss] Way to get average time spent

Justin

Thanks for telling me about perf tool. I think its a really good tool for 
finding hotspots. But I don't know how to test OVS caches with the perf tool.

Greg
Can you please throw some light on this matter. If perf is the right tool for 
getting time spent in EMC,datapath classifier and packet header extraction?
If yes, please tell me the way to do that? Which part I should perf for?


Thanks and Regards


On Wed, Mar 14, 2018 at 4:31 PM, Krish 
> wrote:
Justin

Thanks for telling me about perf tool. I think its a really good tool for 
finding hotspots. But I don't know how to test OVS caches with the perf tool.

Greg
Can you please throw some light on this matter. If perf is the right tool for 
getting time spent in EMC,datapath classifier and packet header extraction?
If yes, please tell me the way to do that? Which part I should perf for?


Thanks and Regards

On Tue, Mar 13, 2018 at 2:08 AM, Justin Pettit 
> wrote:
Greg (cc'd) could probably provide you a better answer, but I suspect the perf 
tool is a good place to start.

--Justin


> On Mar 12, 2018, at 3:24 AM, Krish 
> > wrote:
>
> Hi users,
>
> I need to get the average time spent in packet extraction then in first level 
> cache , second level cache. I don't know the way to measure that.
>
> Can anyone please help me pointing to right direction?
> I think, I need to modify some code. Please guide me if I am right or wrong.
>
>
> Looking forward for a response from someone.
>
> Thanks
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