people February 2020

people@netdevconf.info

4 participants
31 discussions

0x14: nutsnbolts, It is Batching All the Way Down!
by Jamal Hadi Salim 04 Feb '20

04 Feb '20

It is turtles^wbatching all the way down folks! Several parts of the kernel network stack use batching for performance enhancement. Maciej Fijałkowski, Bjorn Topel and Krzysztof Kazimierczak feel we could do a little more. They borrow ideas from other high performance packet processing solutions, such as DPDK, and tweak those ideas to an "XDP first" design - meaning drivers that are optimized for the case when all packets are processed by XDP. In this talk, they describe how they enabled batching at both the driver and XDP level to improve performance for two sample drivers Intel i40e and ice. Maciej et all will share the performance improvements gained and propose some ideas how these batching ideas can equally be applied at other BPF hooks (socket send/recv, traffic control, etc) More info: https://netdevconf.info/0x14-staging/session.html?talk-it-is-batching-all-t… cheers, jamal

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0x14: nutsnbolts, Reducing Kernel Queuing Delays with TCP Window Space Events
by Jamal Hadi Salim 04 Feb '20

04 Feb '20

Existing performance enhancing mechanisms such as TCP auto-tuning or programmatic async(epoll, etc) events such as "ready to send" help applications to sustain high throughput even under high Bandwith-Delay product scenarios. But: the folks at the Tor project have found that when you have thousands of active TCP sockets transmitting high volumes of data, many of which are simultenous (as it is the case in Tor anonymity network) then these mechanisms are insufficient. Local buffer bloat becomes a hindrance. In this talk, David Goulet and Rob Jansen introduce a new async event that helps applications overcome these issues. The new event supplements and extends the current write "ready to send" event that triggers when a socket buffer has free space. David and Rob will present data and go into more detailed description of the problem and then show the effect that such a change could have on performance through a small scale simulation. More info: https://netdevconf.info/0x14-staging/session.html?talk-reducing-kernel-queu… Reminder, registration is now open and early bird is still in effect. https://netdevconf.info/0x14/registration.html cheers, jamal

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0x14: nutsnbolts, Time-travel Linux (network) simulation
by Jamal Hadi Salim 04 Feb '20

04 Feb '20

There are times when you want to recreate a network test that would typically take a while to complete. In addition, when you run the tests, you want the results to be consistent in different runs. In this talk, Johannes Berg and Richard Weinberger describe their solution to this requirement. They introduce a mechanism to do "time travel" in User Mode Linux(UML) with a virtual clock. The time travel mode allows for reproducible testing at significantly faster test execution times; as an example, on a relatively slow laptop: two simulated machines in such a setup can simulate 61 pings, at a default 1 second interval, in about 1.6 seconds real time (as opposed to 61 seconds). More info: https://netdevconf.info/0x14/session.html?talk-time-travel-linux-network-si… Reminder, registration is now open and early bird is still in effect. https://netdevconf.info/0x14/registration.html cheers, jamal

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0x14: nutsnbolts, 5 years of iwd - lessons learned about Linux wireless subsystem
by Jamal Hadi Salim 03 Feb '20

03 Feb '20

The iNet Wireless Daemon aka iwd was created to be an alternative to wpa_supplicant. Iwd provides a more complete solution set for WiFi compared to wpa_supplicant - with a much longwe list of features. Marcel Holtmann will provide insights into iwd architecture and how it takes advantage of kernel features to provide good user experience. In addition, Marcel will go over lessons learned since inception of iwd in the last 5 years. More info: https://netdevconf.info/0x14/session.html?talk-5-years-of-iwd-lessons-learn… Reminder, registration is now open and early bird is still in effect. https://netdevconf.info/0x14/registration.html cheers, jamal

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0x14: nutsnbolts, devlink enhancements for sub functions management
by Jamal Hadi Salim 03 Feb '20

03 Feb '20

New virtualization deployments call out for high density virtual functions with more frequent lifetime recycling. Unfortunately, PCIe SR-IOV has limited function count and large instantiation overhead. A solution to these challenges is to take a PCIE device and "split" it into multiple subdevices. Each subdevice gets its own virtual port(s), queues as well as named resources; Combined with TC and switchdev offloads this approach overcomes the SR-IOV limitations. In this talk Parav Pandit introduces devlink enhancements to manage such sub functions. Parav first discusses how devlink is used to life cycle, configure and deploy accelerated sub functions with eswitch offloads support. He then discusses the plumbing done using virtbus to achieve persistence naming of netdevices and rdma devices. Parav will also cover how such model addresses smartnic use case where a sub-function NIC is hot plugged in host system in a secure manner. More info: https://netdevconf.info/0x14/session.html?talk-devlink-enhancements-for-sub… Reminder, registration is now open and early bird is still in effect. https://netdevconf.info/0x14/registration.html cheers, jamal

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0x14: Moonshot talks + Workshop, Machine Learning For Networking
by Jamal Hadi Salim 02 Feb '20

02 Feb '20

Sorry to dissapoint folks, but we are _not_ going to have any talks on blockchain in 0x14! If this statement infuriates you then please demonstrate your outrage by submiting a proposal when the CFS for 0x15 opens up! Now that we got that out the way... What is Machine Learning? Machine learning (ML) is a subset of artificial intelligence(AI) that lets computer systems solve a specific task without using explicit instructions, relying on patterns and inference instead of human intervention. But How Does ML Apply To Networking? Machine learning can be used to observe patterns in network traffic or configuration and use the resulting data for a variety of things, some sample space: - dynamic congestion control (goodbye named congestion control algos!), see for example applicability of: https://netdevconf.info/0x12/session.html?restructuring-endpoint-congestion… - improve datapath performance - path optimization - anomaly detection from a baseline expectation and using the resulting data either for security or optimization end goals - etc. At 0x14 we have two moonshot talks that look at using ML for networking on Linux. These talks will be part of the ML workshop which is debutting in 0x14. We hope to able to solicit discussions and feedback on the subject and hopefully have this workshop as a fixture in future netdev confs. In the first moonshot talk Marta Plantykow, Piotr Raczynski, Maciej Machnikowski and Pawel Szymanski will discuss an approach to optimize networking performance alongside CPU utilization with ML. Marta et al propose an approach which will use ML to study RSS patterns and the CPU spread and then react dynamically to modify RSS hash parameters to improve CPU spread. The authors will go over the challenges they overcame, show some performance numbers and solicit feedback. More info: https://netdevconf.info/0x14/session.html?talk-performance-optimization-usi… Our second talk is from Maciej Paczkowski, Aleksandra Jereczek, and Patrycja Kochmanska. In this talk Maciej et al integrate into FRR to understand how to best optimize the path selection in an environemnt with multiple simultenous link faults and incestant link flapps. Could routing decisions better helped with ML hooks in the kernel/datapath? Could we make use of offloading some of the algos to AI hardware? The authors will go over the challenges they overcame, and solicit feedback. More info: https://netdevconf.info/0x14/session.html?talk-machine-learning-in-packet-r… Reminder, registration is now open and early bird is still in effect. https://netdevconf.info/0x14/registration.html cheers, jamal

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people February 2020