[ovs-discuss] Mega-flow generation

O Mahony, Billy billy.o.mahony at intel.com
Thu Aug 30 09:24:53 UTC 2018


Hi Sara,

A colleague of mine had a lot of difficulty using dpctl/add-flow to add flow directly to the datapath. And the man-page is a little lukewarm on it’s usage too albeit you are just debugging (ovs-vswitchd (8)-  DATAPATH FLOW TABLE DEBUGGING COMMANDS) . Also you will find that whatever rules you can insert will be very shortly deleted again by the revalidator thread as they will not correspond to any existing ofproto rule.

You should set up flows using ofctl then generate packets to match those flows and you should be able to monitor the netlink messages exchanged between vswitchd and the vswitch .ko as the megaflow is installed to the kernel module. I don’t know how you might monitor the netlink messages - ip-monitor (8) is a possibility. Turning on vswitchd debug in the relevant module is another possibility.

Hope some of that helps,

Billy.



From: Sara Gittlin [mailto:sara.gittlin at gmail.com]
Sent: Thursday, August 30, 2018 9:44 AM
To: O Mahony, Billy <billy.o.mahony at intel.com>
Cc: Ben Pfaff <blp at ovn.org>; ovs-discuss at openvswitch.org
Subject: Re: [ovs-discuss] Mega-flow generation

i think i can 'ride on'  the callback "dpctl_put_flow"  - which is invoked whenever the cli  'ovs-dpctl add-flow' is executed.correct ?

On Thu, Aug 30, 2018 at 10:32 AM Sara Gittlin <sara.gittlin at gmail.com<mailto:sara.gittlin at gmail.com>> wrote:
Billy,
Can you please refer me to the code where we start the megaflow creation to the kernel upon an upcall,  and where we send it to the kernel via the netlink socket ?
what i want to do is - to generate megaflows, based on openflow tables,  not neccesararily upon an upcall, that is not reactive mode and to send to the kernel.
Another question is,  who is responsible to  associate a specific  megaflow  to the appropriate table in the cache ?  is it the kernel module or vswitchd ?
Thank you
-Sara


On Tue, Aug 28, 2018 at 1:12 PM Sara Gittlin <sara.gittlin at gmail.com<mailto:sara.gittlin at gmail.com>> wrote:
Thank you Ben and Billy
-Sara

On Tue, Aug 28, 2018 at 11:27 AM O Mahony, Billy <billy.o.mahony at intel.com<mailto:billy.o.mahony at intel.com>> wrote:
Hi Sara,

This article https://software.intel.com/en-us/articles/ovs-dpdk-datapath-classifier gives practical overview of how megaflows, aka wildcarded or datapath flows, work at least in the ovs-dpdk (userspace datapath) context.

Regards,
Billy

> -----Original Message-----
> From: ovs-discuss-bounces at openvswitch.org<mailto:ovs-discuss-bounces at openvswitch.org> [mailto:ovs-discuss-<mailto:ovs-discuss->
> bounces at openvswitch.org<mailto:bounces at openvswitch.org>] On Behalf Of Ben Pfaff
> Sent: Monday, August 27, 2018 5:10 PM
> To: Sara Gittlin <sara.gittlin at gmail.com<mailto:sara.gittlin at gmail.com>>
> Cc: ovs-discuss at openvswitch.org<mailto:ovs-discuss at openvswitch.org>
> Subject: Re: [ovs-discuss] Mega-flow generation
>
> On Mon, Aug 27, 2018 at 02:46:19PM +0300, Sara Gittlin wrote:
> > Can someone refer me to the code of the megaflow generation process ?
> > Is this process  invoked by an upcall from the kernel module ? like in
> > microflow ?
>
> Did you read the OVS paper?  It's all about megaflows.
> http://www.openvswitch.org/support/papers/nsdi2015.pdf
> _______________________________________________
> discuss mailing list
> discuss at openvswitch.org<mailto:discuss at openvswitch.org>
> https://mail.openvswitch.org/mailman/listinfo/ovs-discuss
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.openvswitch.org/pipermail/ovs-discuss/attachments/20180830/ad7bc520/attachment.html>


More information about the discuss mailing list