Last week was DevConf in Brno, Czech Republic. I was there!

Thorsten Leemhuis gave a talk about What’s up in Kernel Land. This was a general overview about new features and patches that are coming into the Linux kernel targeted at non-kernel developers. I was not the target audience but the talk was fantastic. It was easy to follow and gave a good picture of what the kernel community is doing. I appreciate when non-kernel developers give talks about the kernel since kernel developers can be a bit myopic in our topics (myself included).

Peter Jones talked about Firmware updates on Linux. So long as there has been firmware, there have been firmware bugs. Fixing those bugs involves giving updates. Recent updates to the UEFI firmware specification make it plausible to give firmware updates directly from Linux. This talk described the work to make these Firmware updates actually happen and even included a live demo that did not brick a machine. Having a reliable way to get firwmare updates without needing to boot into Windows is very helpful for improving the overall Linux experience.

There was a talk about performance tuning of RHEL. Most of this was about various userspace knobs that can be set depending on your workload to control aspects like NUMA affinity and page writeback. I’ve worked enough in the memory management area to know how must of the underlying technology works. This talk was useful in showing how to practically make use of these features to improve your system. Having more knowledge available to help with performance issues is always beneficial as a developer.

In a similar theme, there was a talk about solving memory performance problems. This primarily focused on using the perf tool to find and fix cache performance problems. The primary example was variables that are sharing a single cache line. Intel has added new hardware features to make it possible to aggregate cache data and figure out where cache conflicts are occurring. Cache issues can be a pain to solve so it’s great to see perf making this a little easier. Hopefully other architectures will get similar hardware support and integration.

Paul More gave a talk on Lessons from the CII Badge Program. The Core Infrastructure Initiative (CII) came out of the Heartbleed security issue to make the software we rely on more secure. As part of this, the CII has a ‘badge’ program of best practices for open source software. These practices are less “don’t write buffer overflows” and more “are you using source control”. The example in the talk was how well libseccomp complied with the best practices. Overall, libseccomp had good compliance with a few areas to improve. None of the requirements are overly burdensome but they are important for project sustainability.

Peter Robinson gave a talk about architecting a secure IoT platform using Fedora. This was mostly an update on his work driving IoT for Fedora. The goal is to pick several devices and use them as a reference platform for IoT gateways (machine to hook up to tiny IoT devices). Part of this work is to make sure that Fedora doesn’t become the punchline of any IoT jokes so there was a big emphasis on security and what work needs to happen there. I look forward to seeing Fedora used in this buzzword filled space.

There’s a new effort underway to make Fedora run better on laptops within Red Hat and this talk described that effort. The focus is going to be on enabling and testing specific laptops to make sure they work well with Fedora. A big reason bugs go unfixed is because nobody has the time to work on them. Having dedicated people to work on this problem is a huge step in the right direction. Part of this work is also things like making the nVidia driver more usable. Philosophically, I have misgivings about the nv driver but from a usability perspective this is a great effort. This was a nice tie in to a talk about Fedora Workstation on the last day (unfortunately the talk didn’t get recorded).

Rawhide recently brought in gcc7 and the kernel hit a bit of a snag so I was eager to see the talk about cool new gcc7 features. The talk started out explaining -Wimplicit-fallthrough which is designed to catch fall through in switch cases. Of course, sometimes you actually want this behavior so the ‘solution’ is to look for comments like /* fallthrough */. I am not sold on this technique but I can take comfort in the fact that there is a very long thread somewhere debating this. I don’t know where it is, but I am sufficiently convinced that it exists and I don’t want to read it. Most of the rest of the talk was describing other warnings and features, none of which were quite as controversial (although the talk did digress into C++ specification discussion for a bit). It’s always good to see the compiler improving to make programming better.

There does exist a video of my talk about fresh kernels with Fedora. This was an overview of how the upstream kernel release process works and how that drivers a lot of the rebase decisions we make in Fedora. Overall, I was pretty satisfied with how the talk went. I got some good questions and people seemed engaged. I might see about tweaking this talk to give elsewhere.

This was my first time at DevConf and in Brno and I had a fantastic time. There was some hallway track and lots of good times talking with people. Hopefully I’ll get a chance to go back again.