[ovs-dev] [PATCH V2] OF1.5/EXT-334 OXS/Extensible Flow Entry Statistics Support

Satyavalli Rama satyavalli.rama at tcs.com
Fri Jan 5 11:25:17 UTC 2018


Hi Jan and Ben,

Please find the inline responses.


-----Ben Pfaff <blp at ovn.org> wrote: -----
To: Jan Scheurich <jan.scheurich at ericsson.com>
From: Ben Pfaff <blp at ovn.org>
Date: 01/05/2018 02:35AM
Cc: SatyaValli <satyavalli.rama at gmail.com>, "dev at openvswitch.org" <dev at openvswitch.org>, Manasa Cherukupally <manasa.cherukupally at tcs.com>, Pavani Panthagada <p.pavani1 at tcs.com>, Lavanya Harivelam <harivelam.lavanya at tcs.com>, Surya Muttamsetty <muttamsetty.surya at tcs.com>, SatyaValli <satyavalli.rama at tcs.com>
Subject: Re: [ovs-dev] [PATCH V2] OF1.5/EXT-334 OXS/Extensible Flow Entry Statistics Support

On Wed, Jan 03, 2018 at 04:24:06PM +0000, Jan Scheurich wrote:
> > > >
> > > > This Patch provides implementation Existing flow entry statistics are
> > > > redefined as standard OXS(OpenFlow Extensible Statistics) fields for
> > > > displaying the arbitrary flow stats.The existing Flow Stats were renamed
> > > > as Flow Description.
> > > >
> > > > To support this implementation below messages are newly added
> > > >
> > > > OFPRAW_OFPT15_FLOW_REMOVED,
> > > > OFPRAW_OFPST15_FLOW_REQUEST,
> > > > OFPRAW_OFPST15_FLOW_DESC_REQUEST,
> > > > OFPRAW_OFPST15_AGGREGATE_REQUEST,
> > > > OFPRAW_OFPST15_FLOW_REPLY,
> > > > OFPRAW_OFPST15_FLOW_DESC_REPLY,
> > > > OFPRAW_OFPST15_AGGREGATE_REPLY,
> > > >
> > > > The current commit adds support for the new feature in flow statistics
> > > > multipart messages,aggregate multipart messages and OXS support for flow
> > > > removal message, individual flow description messages.
> > > >
> > > > "ovs-ofctl dump-flows" needs to be provided with the arbitrary OXS fields
> > > > for displaying the desired flow stats.
> > > >
> > > > Below are Commands to display OXS stats field wise
> > > >
> > > > Flow Statistics Multipart
> > > > ovs-ofctl dump-flows -O OpenFlow15 <bridge> idle_time
> > > > ovs-ofctl dump-flows -O OpenFlow15 <bridge> packet_count
> > > > ovs-ofctl dump-flows -O OpenFlow15 <bridge> byte_count
> > >
> > > This would break backward compatibility for one of the most frequently used OVS CLI commands. Why don't you introduce a new
> > command such as "ovs-ofctl dump-flow-stats" for the new OXS stats?
> > 
> > I think you might be misinterpreting the meaning here.  It doesn't
> > appear to break compatibility, at least not in a major way, since it
> > doesn't do a lot of updates to the tests that would otherwise be
> > required.
> 
> Perhaps I am missing the point of some of these changes. I understand that OVS needs to support the new extensible OXS flow stats syntax in OpenFlow 1.5 and the differentiated MP request/reply pairs OFPMP_FLOW_DESC (replacing the former OFPMP_FLOW) and OFPMP_FLOW_STATS (just fetching flow stats per flow w/o the rest of the flow data).
> 
> But I don't understand why this should have any impact on the existing CLI command "ovs-ofctl dump-flows" and its output. This tool expressly fetches and displays the complete flow dump from OVS, including match, instructions/actions and statistics. When using OF 1.5 it should transparently apply OFPMP_FLOW_DESC MP request/reply to fetch the data, up to OF 1.4 it should use the original OFPMP_FLOW.
> 
> I can't see any ovs-ofctl use case that would justify the use of the new OFPMP_FLOW_STATS request/reply. The removed data in the reply compared to the full flow description are mainly the instructions, the full match is still there to identify each flow. So cutting down the transferred data volume can hardly be the reason (Note, this may still be different for real OF 1.5 controllers).
> 
> If you believe we should have an ovs-ofctl command anyhow, e.g. for testing purposes, I suggest to introduce a new command or add an option to dump-flows to force use of this particular MP message. The output would be limited to flow match and stats in that case.
> 

As per our understanding and from previous review comments we treated OF1.5+ has two different ways to request and get replies for Flow Stats: FLOW_DESC and FLOW_STATS (which will be even used for Flow Stats Trigger). And we've supported this with the help of two commands

OFPMP_FLOW_DESC - ovs-ofctl dump-flow-desc -O OpenFlow15
OFPMP_FLOW_STATS - ovs-ofctl dump-flows -O OpenFlow15

> The new command to dump aggregate flow stats is of course a welcome addition. It should work irrespectively of the used OpenFlow version with the OFPMP_AGGREGATE_STATS primitive using classic flow stats prior to OF 1.5 and OXS flow stats in OF 1.5.
> 
> All in all I am NACK-ing this patch as it stands.
> 
> Regards, Jan
> 
> BTW: I have played a bit with the patch. The existing ovs-ofctl test cases appear to not break because the changes described in the commit message and the documentation are not effective. The legacy command format "ovs-ofctl dump-flows -O OpenFlow15 <bridge> [<match>]" still produces the complete flow dump including instructions/actions:
> 

We cross checked and tested the patch again on the latest OVS GIT and we haven't observed any of these issues. Could you please share your topology and any other configurations for better understanding of the issue:

Please find logs for the same with the below configuration / flow-add rules:

# git log --after="2018-01-03"
commit b02bf23fe3caa011a842f22fc802d77f989dd81b
Author: SatyaValli <satyavalli.rama at tcs.com>
Date:   Thu Jan 4 16:59:03 2018 +0530

    OF_Extensible_Statistics

commit 77b7d23230fecf774c2a707b7b42fdb8a65a8892
Author: Ben Pfaff <blp at ovn.org>
Date:   Wed Jan 3 16:11:02 2018 -0800

    ofp-actions: Log version, vendor, and type of unknown actions being parsed.
    
    This may help debugging difficult controller problems.
    
    Reported-by: Su Wang <suwang at vmware.com>
    Signed-off-by: Ben Pfaff <blp at ovn.org>
    Acked-by: Justin Pettit <jpettit at ovn.org>


# ovs-vsctl --version
ovs-vsctl (Open vSwitch) 2.8.90
DB Schema 7.15.1

# ovs-ofctl add-flow -O OpenFlow15 br0 icmp,reset_counts,check_overlap,actions=normal

# ovs-ofctl add-flow -O OpenFlow15 br0 udp,tp_dst=200,actions=normal


# ovs-ofctl add-flow -O OpenFlow15 br0 tcp,tp_src=100,actions=normal


> # ovs-ofctl -Oopenflow15 dump-flow-desc br0
> OFPST_FLOW_DESC reply (OF1.5) (xid=0x2):
>  cookie=0x0, duration=90.515s, table=0, n_packets=0, n_bytes=0, reset_counts idle_age=840, hard_age=32766, in_port="br0-ns1" actions=output:"br0-ns2"
>  cookie=0x0, duration=90.507s, table=0, n_packets=0, n_bytes=0, reset_counts idle_age=840, hard_age=32766, in_port="br0-ns2" actions=output:"br0-ns1"
>  cookie=0x0, duration=850.125s, table=0, n_packets=2, n_bytes=180, idle_age=849, hard_age=32766, priority=0 actions=NORMAL
> 
##Flow Description Dump:
## ovs-ofctl dump-flow-desc -O OpenFlow15 br0
OFPST_FLOW_DESC reply (OF1.5) (xid=0x2):
 cookie=0x0, duration=446.251s, table=0, n_packets=0, n_bytes=0, check_overlap reset_counts idle_age=0, hard_age=0, icmp actions=NORMAL
 cookie=0x0, duration=440.523s, table=0, n_packets=0, n_bytes=0, idle_age=0, hard_age=0, udp,tp_dst=200 actions=NORMAL
 cookie=0x0, duration=436.579s, table=0, n_packets=0, n_bytes=0, idle_age=0, hard_age=0, tcp,tp_src=100 actions=NORMAL
 cookie=0x0, duration=3451.715s, table=0, n_packets=0, n_bytes=0, idle_age=0, hard_age=0, priority=0 actions=NORMAL

## ovs-ofctl dump-flow-desc -O OpenFlow15 br0 packet_count
OFPST_FLOW_DESC reply (OF1.5) (xid=0x4):
 cookie=0x0, duration=338.579s, table=0, n_packets=32918, n_bytes=0, check_overlap reset_counts idle_age=0, hard_age=0, icmp actions=NORMAL
 cookie=0x0, duration=332.851s, table=0, n_packets=16417, n_bytes=0, idle_age=0, hard_age=0, udp,tp_dst=200 actions=NORMAL
 cookie=0x0, duration=328.907s, table=0, n_packets=12309, n_bytes=0, idle_age=0, hard_age=0, tcp,tp_src=100 actions=NORMAL
 cookie=0x0, duration=3344.043s, table=0, n_packets=53604586, n_bytes=0, idle_age=0, hard_age=0, priority=0 actions=NORMAL

> # ovs-ofctl -Oopenflow15 dump-flows br0
>  cookie=0x0, duration=94.634s, table=0, n_packets=0, n_bytes=0, idle_age=844, hard_age=0, in_port="br0-ns1" actions=output:"br0-ns2"
>  cookie=0x0, duration=94.626s, table=0, n_packets=0, n_bytes=0, idle_age=844, hard_age=0, in_port="br0-ns2" actions=output:"br0-ns1"
>  cookie=0x0, duration=854.244s, table=0, n_packets=2, n_bytes=180, idle_age=853, hard_age=0, priority=0 actions=NORMAL
> 
> The only difference appears to be that the flow property reset_counts is missing and that hard_age seems corrupt in the new ovs-ofctl dump-flow-desc.
> 
> Furthermore, specifying any OXS field at the end of ovs-ofctl dump-flows <bridge> is without effect:
> 
> # ovs-ofctl -Oopenflow15 dump-flows br0 duration
>  cookie=0x0, duration=173.536s, table=0, n_packets=0, n_bytes=0, idle_age=923, hard_age=0, in_port="br0-ns1" actions=output:"br0-ns2"
>  cookie=0x0, duration=173.528s, table=0, n_packets=0, n_bytes=0, idle_age=923, hard_age=0, in_port="br0-ns2" actions=output:"br0-ns1"
>  cookie=0x0, duration=933.146s, table=0, n_packets=2, n_bytes=180, idle_age=932, hard_age=0, priority=0 actions=NORMAL
> 
> # ovs-ofctl -Oopenflow15 dump-flows br0 packet_count
>  cookie=0x0, duration=184.600s, table=0, n_packets=0, n_bytes=0, idle_age=934, hard_age=0, in_port="br0-ns1" actions=output:"br0-ns2"
>  cookie=0x0, duration=184.593s, table=0, n_packets=0, n_bytes=0, idle_age=934, hard_age=0, in_port="br0-ns2" actions=output:"br0-ns1"
>  cookie=0x0, duration=944.211s, table=0, n_packets=2, n_bytes=180, idle_age=943, hard_age=0, priority=0 actions=NORMAL
> 

As OXS_OF_DURATION field is mandatory as per OF 1.5+ Spec for tracking the age of flow entry in the switch, we've kept it as a default field. The other fields OXS_OF_PACKET_COUNT and OXS_OF_BYTE_COUNT are kept as optional.

##Flow Status Dump:

## ovs-ofctl dump-flows -O OpenFlow15 br0 duration

 cookie=0x0, duration=235.211s, table=0, n_packets=0, n_bytes=0, idle_age=0, hard_age=0, icmp actions=NORMAL

 cookie=0x0, duration=229.483s, table=0, n_packets=0, n_bytes=0, idle_age=0, hard_age=0, udp,tp_dst=200 actions=NORMAL

 cookie=0x0, duration=225.539s, table=0, n_packets=0, n_bytes=0, idle_age=0, hard_age=0, tcp,tp_src=100 actions=NORMAL

 cookie=0x0, duration=3240.675s, table=0, n_packets=0, n_bytes=0, idle_age=0, hard_age=0, priority=0 actions=NORMAL

The OXS field value reflection is based on the flow match

## ovs-ofctl dump-flows -O OpenFlow15 br0 packet_count

 cookie=0x0, duration=176.872s, table=0, n_packets=1102, n_bytes=0, idle_age=0, hard_age=0, icmp actions=NORMAL

 cookie=0x0, duration=171.144s, table=0, n_packets=544, n_bytes=0, idle_age=0, hard_age=0, udp,tp_dst=200 actions=NORMAL

 cookie=0x0, duration=167.200s, table=0, n_packets=408, n_bytes=0, idle_age=0, hard_age=0, tcp,tp_src=100 actions=NORMAL


 cookie=0x0, duration=3182.336s, table=0, n_packets=53592657, n_bytes=0, idle_age=0, hard_age=0, priority=0 actions=NORMAL

## ovs-ofctl dump-flows -O OpenFlow15 br0 packet_count,idle_time

 cookie=0x0, duration=143.448s, table=0, n_packets=1102, n_bytes=0, idle_age=5, hard_age=0, icmp actions=NORMAL

 cookie=0x0, duration=137.720s, table=0, n_packets=544, n_bytes=0, idle_age=5, hard_age=0, udp,tp_dst=200 actions=NORMAL

 cookie=0x0, duration=133.776s, table=0, n_packets=408, n_bytes=0, idle_age=5, hard_age=0, tcp,tp_src=100 actions=NORMAL

 cookie=0x0, duration=3148.912s, table=0, n_packets=53592655, n_bytes=0, idle_age=0, hard_age=0, priority=0 actions=NORMAL

> When specifying it in addition to some filter match it is rejected:
> 
> # ovs-ofctl -Oopenflow15 dump-flows br0 in_port="br0-ns1" packet_count
> ovs-ofctl: 'dump-flows' command takes at most 2 arguments

There is a slight syntax mismatch, please find the below dumps with match field:

##Dumps with Match Field:
## ovs-ofctl dump-flows -O OpenFlow15 br0 tcp,packet_count
 cookie=0x0, duration=549s, table=0, n_packets=42146, n_bytes=0, idle_age=0, hard_age=0, tcp,tp_src=100 actions=NORMAL

## ovs-ofctl dump-flows -O OpenFlow15 br0 tcp,byte_count
 cookie=0x0, duration=565.577s, table=0, n_packets=0, n_bytes=2275884, idle_age=0, hard_age=0, tcp,tp_src=100 actions=NORMAL

## ovs-ofctl dump-flows -O OpenFlow15 br0 udp,packet_count
 cookie=0x0, duration=600.984s, table=0, n_packets=56200, n_bytes=0, idle_age=0, hard_age=0, udp,tp_dst=200 actions=NORMAL

## ovs-ofctl dump-flows -O OpenFlow15 br0 icmp,packet_count
 cookie=0x0, duration=614.544s, table=0, n_packets=112611, n_bytes=0, idle_age=0, hard_age=0, icmp actions=NORMAL

## ovs-ofctl dump-flow-desc -O OpenFlow15 br0 icmp,packet_count
OFPST_FLOW_DESC reply (OF1.5) (xid=0x4):
 cookie=0x0, duration=625.217s, table=0, n_packets=112611, n_bytes=0, check_overlap reset_counts idle_age=0, hard_age=0, icmp actions=NORMAL

## ovs-ofctl dump-aggregate -O OpenFlow15 br0 icmp,packet_count
OFPST_AGGREGATE reply (OF1.5) (xid=0x4): packet_count=112611 byte_count=0 flow_count=1

SatyaValli, can you respond to this?


Thanks & Regards
Satya Valli
Tata Consultancy Services
Mailto: satyavalli.rama at tcs.com
Website: http://www.tcs.com
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