[ovs-discuss] OVS Flow Stats

Yanqin Wei (Arm Technology China) Yanqin.Wei at arm.com
Mon Jul 29 03:10:57 UTC 2019


Hi Ramneek,

I only run multi-core scaling case in OVS-DPDK datapath. The setup is similar with yours, NIC2NIC , RSS key load balance, 4 queues, 4 cores. In the OVS-DPDK datapath, there is also dev stat update which is locked by spinlock. But I observed multi-core scaling is good, 4-cores performance is around 4 times throughput of single-core.

So I have no idea of why kernel datapath has performance issue. Maybe somebody working on kernel datapath could help you.

Best Regards,
Wei Yanqin

From: Ramneek Sekhon <ramneeksekhon at gmail.com>
Sent: Monday, July 29, 2019 9:16 AM
To: Yanqin Wei (Arm Technology China) <Yanqin.Wei at arm.com>
Cc: ovs-discuss at openvswitch.org
Subject: Re: [ovs-discuss] OVS Flow Stats

Dear  Wei Yanqin

Thanks for your response. Any help in this regard shall be greatly appreciated.

Yes, I am running ovs (kernel mode) on manycore machine. All the traffic received from pktgen via port 0 is simply forwarded to port 1 of the  NIC, and performance is measured in the pktgen.
The ovs_dp_process_packet calls ovs_execute_actions,  ovs_flow_stats_update and ovs_flow_tbl_lookup_stats.
The ovs_flow_stats_update involves __raw_spin_locks which might affect the performance and scalability on manycore systems.
I used the perf and flamegraphs to trace the code path to find the bottlenecks.

Please let me know if any additional information is required. I am interested in diabling/bypassing the flow stats update to see the effect on the performance.

Thanks and Regards
Ramneek



On Fri, Jul 26, 2019 at 4:32 PM Yanqin Wei (Arm Technology China) <Yanqin.Wei at arm.com<mailto:Yanqin.Wei at arm.com>> wrote:
Hi Ramneek ,

I am just curious of how much performance dropped by this spin lock.  Do you run ovs in multi-cores? What is your scenario for this test? I mean the platform ,NIC, VM, traffic pattern and configuration.

If you could provide more specific information, it could help community to improve it.

Best Regard,
Wei Yanqin

From: ovs-discuss-bounces at openvswitch.org<mailto:ovs-discuss-bounces at openvswitch.org> <ovs-discuss-bounces at openvswitch.org<mailto:ovs-discuss-bounces at openvswitch.org>> On Behalf Of Ramneek Sekhon
Sent: Wednesday, July 24, 2019 8:42 AM
To: ovs-discuss at openvswitch.org<mailto:ovs-discuss at openvswitch.org>
Subject: [ovs-discuss] OVS Flow Stats

Hi All
How can we disable flow stats in OVS, as it includes spin locks that affect the overall TX/RX performance.

Thanks and Regards
Ramneek

IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you.
IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.openvswitch.org/pipermail/ovs-discuss/attachments/20190729/c3cb7d59/attachment-0001.html>


More information about the discuss mailing list