Daniel Lezcano
Kernel Engineer & Po...
Linaro
Standard Ticket
Daniel worked in 1998 in the Space Industry and Air traffic management for distributed system project in life safety constraints. He acquired for this project a system programming expertise. He joined IBM in 2004 and since this date he does kernel hacking and pushed upstream the resource virtualization with the namespaces. He is the author and former maintainer of the Linux Container (LXC). In 2012, he joined Linaro to work in the power management team. Deeply involved in the power management improvements for the different members of Linaro, he continues to contribute and maintain some parts of the Linux kernel in the power management area. Currently, he is maintaining CPUidle for the ARM architecture, the timer drivers and the thermal framework.
Talks
MAD24-207 Align the kernel upstream approach with the userspace in power management
Session
- Wednesday, 15 May 11:10 - 11:35
- Room: Session 3 | Tenerife II
The awareness of the cost resulting from the Android kernel fragmentation led to a convergence to a Linux kernel upstream support based on a Generic Kernel Interface (GKI). The effort for supporting upstream SoCs is unfortunately slowed down when the kernel and the userspace have to be aligned. The interfaces presented by the custom kernels are not standardized. Consequently, the userpsace which is relying on those interfaces can no longer interact with the kernel when the upstream support is brought up and the overall power management can not be enabled in Android. Linaro has developed a set of userspace components designed to be generic in order to provide basic power management support with the Linux kernel upstream enablement. On the other side, efforts are made in the background to bring standardized power management interfaces from the kernel and have the generic userspace components to take advantage of them. This presentation will give the architecture and the approach of the different userspace components. It will explain how to use them for an upstream platform enablement and will discuss the future of those for a more complete solution.
MAD24-211 Boot time optimization project
Session
- Wednesday, 15 May 11:45 - 12:10
- Room: Session 2 | Tenerife I
Systems with industry standards like automotive have strong requirements to ensure the boot process is fast enough to put the system in a ready state. Others consider the boot time less important when the system is powered up but want a quick wake up from an hibernate state. The platform boot time optimization is usually platform specific and use case centric which implies a dedicated set of changes. Those will be deprecated with a new hardware having different drivers or a new software version which may introduce latencies in the boot time process. The boot time optimization project aims to put in place a continuous integration loop to monitor the boot timings and detect regressions over updates. In addition, from an engineering point of view, it identifies a set of changes to be done in the different steps of the boot chain, from the firmware to the userspace. This presentation will describe the project which is split into two parts. The first part will present the boot time continuous integration architecture. We will also discuss the boot timings information to be passed along the different components of the boot chain and how to standardize them in order to retrieve the information in the monitoring process. The second part will list a set of identified bottlenecks responsible for latencies in the boot process. We will propose a way to fix them up and discuss the solutions. It is also an opportunity to share our experience and point out other bottlenecks we may have missed.