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LinuxCon North America - Linux Plumbers Conference Shared Track [clear filter]
Wednesday, September 18
 

10:50am

Advances in Validation of Concurrent Software - Paul E. McKenney, IBM
Validation of concurrent software that runs on a billion devices is challenging.  In this case, "one in a million" bugs will occur a thousand times.  Some projects have worked hard to meet this challenge.  The Linux kernel has added -next testing for pre-merge-window patches, automated randconfig build/boot/test of maintainer-tree commits, and the Trinity syscall-malice tool.  In addition, validation tools such as Coccinelle, lockdep, sparse, and valgrind have also helped squash a great many nasty bugs.  However, improvements reliability are inevitably consumed by increasingly aggressive usage, which of course exposes more problems, requiring fixes and more validation.  This talk will look at some ways that this validation might be carried out, ranging from even more aggressive testing to bleeding-edge verification techniques.

Audience: Aggresssive developers and testers.

Speakers
avatar for Paul McKenney

Paul McKenney

Distinguished Engineer, IBM Linux Technology Center, Beaverton
Paul E. McKenney is a Distinguished Engineer with the IBM Linux Technology Center, where he maintains the RCU implementation within the Linux kernel. He has been coding for four decades, more than half of that on parallel hardware. His prior lives include the DYNIX/ptx kernel at Sequent... Read More →


Wednesday September 18, 2013 10:50am - 11:40am
Celestin A

10:50am

Capture and Replay Hardware Behaviour for Bug Reporting and Regression Testing - Martin Pitt, Canonical
Software stacks that interact with hardware such as Desktop power management, GNOME's gvfs, or handling of multiple monitors and USB devices have traditionally been hard to debug. For a developer it is difficult to reproduce problems and write regression tests without having access to the problematic hardware.  Recently there has been some progress in this area with dbusmock and umockdev. This talk introduces the current state of the art and ends in a group discussion about the needs of particular projects: How can we cover other areas like network devices? Which kinds of hardware and software
projects would benefit most from recording the behaviour of real hardware and replaying it on developer's machines and test suites?

You should be familiar with Linux userspace hardware handling (sysfs, /dev, uevents, D-BUS, etc.) and be interested in QA.

Speakers
avatar for Martin Pitt

Martin Pitt

Upstream QA engineer, Canonical Ltd.
Since 2004 Pitt has worked as an Ubuntu Platform team engineer at Canonical Ltd, in various roles (security, desktop, project mgmt, release engineering). Presently Pitt is a QA team engineer, focusing on QA technology research and upstream QA (mostly GNOME and Linux plumbing). Pitt... Read More →


Wednesday September 18, 2013 10:50am - 11:40am
Celestin C

10:50am

Using PREEMPT_RT Linux, More Than Just the Kernel - Steven Rostedt, Red Hat

There are a few flavors of real-time Linux out in the world. One of the most popular is the PREEMPT_RT kernel, which is slowly making its way into mainline Linux. In the past, I have given presentations describing what PREEMPT_RT does to Linux to make it real-time. But using PREEMPT_RT, you need to know a lot more than just the kernel. A real-time OS requires understanding everything from the hardware you use, the kernel, as well as the applications that sit on top. This talk will be a crash course into how to set up your environment using PREEMPT_RT Linux, explaining things like priorities for interrupts, how softirq's are done, using the priority inheritance mutexes, and other techniques required to avoid the gotcha's that real-time can get you with.


Speakers
avatar for Steven Rostedt

Steven Rostedt

Principal Software Engineer, Red Hat Inc
Steven Rostedt works for Red Hat and is the main developer for their Real Time kernel. Steven is the maintainer of the Real-Time stable releases. He works upstream mainly developing and maintaining ftrace (the official tracer of the Linux kernel). He also maintains trace-cmd and kernelshark... Read More →


Wednesday September 18, 2013 10:50am - 11:40am
Celestin B

11:50am

Bare Metal Performance, Timekeeping, and Energy Efficiency - Paul McKenney, IBM
Database, high-performance computing (HPC), and real-time developers have often asked: "Can't you get the kernel out of the way?". Recent adaptive-idle work permits just that: Linux is there when you need it, but if you follow a few simple rules, it is out of your way otherwise. This approach will provide bare-metal multicore performance and scalability to databases as well as to HPC and real-time applications. However, timekeeping requires that at least one CPU continue in high-power mode if any non-idle execution is in flight. Unfortunately, simple code to determine if all CPUs are idle is not scalable. This talk will give an overview of adaptive idle and outline some of the work to scalably determine whether the timekeeping CPU can go into low-power mode while avoiding any embarrassing time-skew incidents.

Speakers
avatar for Paul McKenney

Paul McKenney

Distinguished Engineer, IBM Linux Technology Center, Beaverton
Paul E. McKenney is a Distinguished Engineer with the IBM Linux Technology Center, where he maintains the RCU implementation within the Linux kernel. He has been coding for four decades, more than half of that on parallel hardware. His prior lives include the DYNIX/ptx kernel at Sequent... Read More →


Wednesday September 18, 2013 11:50am - 12:40pm
Celestin B

11:50am

Binary Compatibility for Library Developers - Thiago Macieira, Intel
The C and C++ standards define what constitutes a well-formed program. However, they steer clear of any issues related to ABI, binary compatibility, and even modern dynamic loading of libraries. Yet developers for libraries are often faced with understanding and dealing with those issues that are out-of-scope for the standards. Far from an impossible task, there are simple guidelines, checklists, tooling, and processes that can be relied upon to guarantee binary compatibility between releases. Using them, it is possible to maintain large libraries compatible with previous versions for a long time, across multiple releases.

This presentation will talk about those real-world problems and their solutions, heavily drawing upon the solutions used by both Qt and KDE. It will mostly focus on issues facing libraries on Linux, but will give hints also for cross-platform portability.

Speakers
avatar for Thiago Macieira

Thiago Macieira

Engineer, Open Source Technology Center, Intel
Thiago Macieira holds a double degree in Engineering and an MBA. He has been involved in several Open Source projects for over 15 years and is an experienced C++ developer, having spent the better part of the last 10 years developing Qt and Qt-based software. He has been involved... Read More →


Wednesday September 18, 2013 11:50am - 12:40pm
Celestin A

2:00pm

Massively Multi-Core Systems or I Have Enough CPUs, Now What? - Gilad Ben-Yossef, EZchip Semiconductor Inc.
NPS-400 is a 256 cores and 4,096 hardware threads SoC running SMP Linux built to process 400 Gbps of network traffic in a Linux user space application. Building Linux support for it touched on several architectural issues that are of interest to the Linux developer community at large as massively multi-core systems becomes more common place. This talk will focus on what happens when you have enough CPUs to dedicate a CPU per task and the balance shifts from scheduling CPU time slices to keeping the OS from interfering with a user process running on a dedicated CPU assigned solely to it. Topics covered include CPU isolation, IPI and work queue cross CPU interference and the dynamic tick feature.

The talk will be useful to engineers working to lower the latency and jitter of real time CPU bound applications and kernel developers interested in enabling Linux to serve these needs.


Speakers
avatar for Gilad Ben Yossef

Gilad Ben Yossef

Principal Software Engineer, Arm
Gilad Ben-Yossef is a principal software engineer working at Arm on upstream kernel security at large and Arm TrustZone CryptoCell support in particular. Gilad is the co-author of O’Reilly’s “Building Embedded Linux Systems” 2nd edition, co-founder of the Israeli FOSS NGO... Read More →


Wednesday September 18, 2013 2:00pm - 2:50pm
Celestin B

2:00pm

UEFI and ACPI for ARM - Graeme Gregory, Linaro
As ARM and ARM64 move out of gadgets and into more PC like hardware, there has been an increasing demand for the same tools to manage these devices as already exists in x86 world. Linaro has been working on UEFI and ACPI on arm/arm64 hardware and this talk is a summary of the current status of the work and the direction that will be taken in the future. We will show the areas of change to the ARM platform boot sequence, change to the ACPI core code, and change to drivers to support ACPI.

The target audience for this talk is kernel developers interested in enterprise server type hardware controlled by UEFI and ACPI during its boot and run cycle, UEFI/ACPI kernel developers who have been working on x86 and interested in the changes required for arm/arm64 support for these standards, and finally those kernel developers who are working on arm/arm64 systems interested in UEFI/ACPI support.

Speakers
GG

Graeme Gregory

Engineering Manager, Linaro Ltd
Graeme is a Kernel developer at Linaro as part of the Enterprise Group working on ACPI for arm/arm64 platforms. He is an OpenEmbedded and Ångström developer and ex board and technical steering committee member. He was previously involved with PMIC drivers while at Slimlogic and... Read More →


Wednesday September 18, 2013 2:00pm - 2:50pm
Celestin A

3:00pm

Page Migration for IOMMU Enhanced Hardware - Tomasz Stanislawski, Samsung

Support for page migration in IOMMU subsystem is presented. This is essential for usage of memory from Contiguous Memory Allocator by IOMMU enhanced hardware. Adding a support for migration requires extensions to DMA framework and fault handling to IOMMU domain API. Migration can be realized by using utilizing code for anonymous pages by introducing a fake mm_struct. Use migrate callback delivered by a new file system dedicated. Other method is introducing a new page type (besides file, anon, and kms). All kinds of mechanism are discussed in detail. Moreover, methods for handling from simultaneous faults from both IOMMU and CPU during migration are described.


Speakers
TS

Tomasz Stanislawski

Software Engineer, Samsung Electronics Polska Sp. z o.o.
Tomasz is a software developer from Samsung Electronics, and a member of the Linux Kernel Development group in the Polish division of Samsung in principle. He is also a maintainer of s5p-tv driver, as well as a contributor to V4L2 framework and DMABUF and DRM and recently to SMACK... Read More →


Wednesday September 18, 2013 3:00pm - 3:50pm
Celestin B

3:00pm

Readme.README: Optimizing Legibility on Mobile Devices - Nathan Willis, LWN.net
Mobile users' attention is measured in "glance time"—because split seconds separate an attentive user from a distracted one, and a happy user from a fatigued one. Designing for readability involves far more than just increasing the text size; fortunately the mobile Linux stack makes it practical to deploy a product that is legible in adverse conditions and eye-pleasing when fully engaged.  This session will explore the research on UI readability, from driver distraction in IVI systems to high-DPI displays, then examine the current state of mobile Linux with regard to legibility. Finally, we will discuss concrete steps that app developers and platform vendors can take to improve their UI readability on phones, tablets, and other devices—with sacficing design originality.

App and mobile platform developers with UI/UX design experience welcome. Moderate technical experience expected.

Speakers
NW

Nathan Willis

Consultant, Glyphography
Nate Willis is a writer and consultant who has been an active member of the free-software community for longer than he cares to remember. He currently develops open-source fonts, works on type-related free-software projects, and advocates for open standards within the font-development... Read More →


Wednesday September 18, 2013 3:00pm - 3:50pm
Celestin A

4:00pm

Secure Boot and The MOK Concept - Vojtěch Pavlík, SUSE
I want to follow up on last year's presentation of Matthew Garret's presentation on Secure Boot in Linux, going into more detail on the MOK concept and explaining the state of the implementation, the acceptance of the Linux-specific parts by the hardware industry, political tensions, as well as remaining challenges, including how Secure Boot should interact with hibernation and kexec.

The content of this presentation will be technical, although not very heavy. The target audience is thus Linux developers, system administrators, but the content will also be accessible to experienced Linux users.

Speakers
VP

Vojtech Pavlik

Director SUSE Labs, SUSE
Vojtěch Pavlík is the director of SUSE Labs, a department of SUSE, a part of Micro Focus, a billion dollar software powerhouse. SUSE Labs develop,in cooperation with the open source community, core components of the Linux operating system - kernel, compiler and other tools. In his... Read More →


Wednesday September 18, 2013 4:00pm - 4:50pm
Celestin B

4:00pm

Vampire Mice: How USB PM Impacts You - Sarah Sharp, Intel
Did you know that your innocent USB mouse is actually a power-hungry battery-draining monster? This talk explores the impact of USB devices on platform power consumption, along with current (and future) tools to tame the monster. USB devices have always been battery eaters, keeping the whole platform in higher power states, including CPUs and chipsets. The aim of this talk is to educate users and developers on how USB devices impact their battery life, and start a discussion on how the Linux community can improve USB power management.

The first part of the talk targets users of all skill levels, and the second part of the talk will be a developer-focused discussion on creating new tools for crowd-sourced USB power management testing.  Systemd, udev, Linux distros, and kernel developers should participate in this conversation.

Speakers
SS

Sarah Sharp

Yocto/Embedded Developer, Intel
Sarah Sharp is a software engineer at Intel's Open Source Technology Center. Sarah is the author of the Linux kernel USB 3.0 driver, and is currently working as an embedded software developer with the Yocto Project. As the coordinator for the Linux kernel project within the FOSS Outreach... Read More →


Wednesday September 18, 2013 4:00pm - 4:50pm
Celestin A