Kernel Recipes 2019 - ftrace: Where modifying a running kernel all startedAnne Nicolas
Ftrace’s most powerful feature is the function tracer (and function graph tracer which is built from it). But to have this enabled on production systems, it had to have its overhead be negligible when disabled. As the function tracer uses gcc’s profiling mechanism, which adds a call to “mcount” (or more recently fentry, don’t worry if you don’t know what this is, it will all be explained) at the start of almost all functions, it had to do something about the overhead that causes. The solution was to turn those calls into “nops” (an instruction that the CPU simply ignores). But this was no easy feat. It took a lot to come up with a solution (and also turning a few network cards into bricks). This talk will explain the history of how ftrace came about implementing the function tracer, and brought with it the possibility of static branches and soon static calls!
Steven Rostedt
This talk will provide several examples of how Facebook engineers use BPF to scale the networking, prevent denial of service, secure containers, analyze performance. It’s suitable for BPF newbies and experts.
Alexei Starovoitov, Facebook
Kernel Recipes 2019 - ftrace: Where modifying a running kernel all startedAnne Nicolas
Ftrace’s most powerful feature is the function tracer (and function graph tracer which is built from it). But to have this enabled on production systems, it had to have its overhead be negligible when disabled. As the function tracer uses gcc’s profiling mechanism, which adds a call to “mcount” (or more recently fentry, don’t worry if you don’t know what this is, it will all be explained) at the start of almost all functions, it had to do something about the overhead that causes. The solution was to turn those calls into “nops” (an instruction that the CPU simply ignores). But this was no easy feat. It took a lot to come up with a solution (and also turning a few network cards into bricks). This talk will explain the history of how ftrace came about implementing the function tracer, and brought with it the possibility of static branches and soon static calls!
Steven Rostedt
This talk will provide several examples of how Facebook engineers use BPF to scale the networking, prevent denial of service, secure containers, analyze performance. It’s suitable for BPF newbies and experts.
Alexei Starovoitov, Facebook
Configuring an embedded Linux system with a read-only rootfs has many advantages: reduced wear on flash memory; easier to update and trivial factory reset being among them. This presentation shows you how
My presentation in SDCC 2012 (http://sdcc.csdn.net/index_en.html). The video recording of this session is available at http://v.csdn.hudong.com/s/article.html?arcid=2810640
Kernel Recipes 2017: Using Linux perf at NetflixBrendan Gregg
Talk for Kernel Recipes 2017 by Brendan Gregg. "Linux perf is a crucial performance analysis tool at Netflix, and is used by a self-service GUI for generating CPU flame graphs and other reports. This sounds like an easy task, however, getting perf to work properly in VM guests running Java, Node.js, containers, and other software, has been at times a challenge. This talk summarizes Linux perf, how we use it at Netflix, the various gotchas we have encountered, and a summary of advanced features."
Slides from Openworl 2019. A look at how to safely (and unsafely) kill sessions in the Oracle database, and how to perhaps avoid killing them altogether.
A set of rules and best practices to write bash shell scripts. Following these rules, you will have less programming errors and spend less time debugging.
It also shows and explains a lot of features from bash you didn't event know existed :
Pattern removal: ${var##*/}
StrReplace: ${var//search/replace}
Options: set -o pipefail -o nounset -o noclobber
And many more...
Slides fra InfInIT arrangement i interessegruppen for Embedded Systems Engineering
http://www.infinit.dk/dk/arrangementer/tidligere_arrangementer/sweet---a-tool-for-wcet-flow-analysis.htm
There is a surge in number of sensors / devices that are getting connected under the umbrella of Internet-Of-Things (IoT). These devices need to be integrated into the Android system and accessed via applications, which is covered in the course. Our Android system development course curriculum over weekends with practicals ensures you learn all critical components to get started.
Android devices running on battery need to be optimized for power.
When taking a look at the CPU this optimization starts typically with the race to idle, meaning to go to finish the workload as fast as possible. However typical Android devices are running on a SoC with many other parts like GPU, hardware decoders, sensors, 2G/3G/4G/Wifi modules...
All these parts need to be optimized to reduce the power consumption, but the biggest part of the problem/solution are applications themselves.
Guessing what software is actually causing high power consumption and mitigating it aren't simple tasks. In this session You will explore typical causes of high power consumption, how to debug them and provide possible solutions.
Android provides a number of APIs, OS tricks, and developer tools around power consumption, you will also get to know, learn, and understand them through this talk.
Configuring an embedded Linux system with a read-only rootfs has many advantages: reduced wear on flash memory; easier to update and trivial factory reset being among them. This presentation shows you how
My presentation in SDCC 2012 (http://sdcc.csdn.net/index_en.html). The video recording of this session is available at http://v.csdn.hudong.com/s/article.html?arcid=2810640
Kernel Recipes 2017: Using Linux perf at NetflixBrendan Gregg
Talk for Kernel Recipes 2017 by Brendan Gregg. "Linux perf is a crucial performance analysis tool at Netflix, and is used by a self-service GUI for generating CPU flame graphs and other reports. This sounds like an easy task, however, getting perf to work properly in VM guests running Java, Node.js, containers, and other software, has been at times a challenge. This talk summarizes Linux perf, how we use it at Netflix, the various gotchas we have encountered, and a summary of advanced features."
Slides from Openworl 2019. A look at how to safely (and unsafely) kill sessions in the Oracle database, and how to perhaps avoid killing them altogether.
A set of rules and best practices to write bash shell scripts. Following these rules, you will have less programming errors and spend less time debugging.
It also shows and explains a lot of features from bash you didn't event know existed :
Pattern removal: ${var##*/}
StrReplace: ${var//search/replace}
Options: set -o pipefail -o nounset -o noclobber
And many more...
Slides fra InfInIT arrangement i interessegruppen for Embedded Systems Engineering
http://www.infinit.dk/dk/arrangementer/tidligere_arrangementer/sweet---a-tool-for-wcet-flow-analysis.htm
There is a surge in number of sensors / devices that are getting connected under the umbrella of Internet-Of-Things (IoT). These devices need to be integrated into the Android system and accessed via applications, which is covered in the course. Our Android system development course curriculum over weekends with practicals ensures you learn all critical components to get started.
Android devices running on battery need to be optimized for power.
When taking a look at the CPU this optimization starts typically with the race to idle, meaning to go to finish the workload as fast as possible. However typical Android devices are running on a SoC with many other parts like GPU, hardware decoders, sensors, 2G/3G/4G/Wifi modules...
All these parts need to be optimized to reduce the power consumption, but the biggest part of the problem/solution are applications themselves.
Guessing what software is actually causing high power consumption and mitigating it aren't simple tasks. In this session You will explore typical causes of high power consumption, how to debug them and provide possible solutions.
Android provides a number of APIs, OS tricks, and developer tools around power consumption, you will also get to know, learn, and understand them through this talk.