Tips for reducing empty loops in Linux kernel and reducing system energy consumption

Article Title: tips for reducing empty loops in Linux kernel and reducing system energy consumption. Linux is a technology channel of the IT lab in China. Includes basic categories such as desktop applications, Linux system management, kernel research, embedded systems, and open source.

If you do not spend more time watching the table, you will have more time.

In layman's terms, this is the basic principle of an important change in the Linux kernel. programmers hope this change can improve the efficiency of Linux. The new Linux operating system will adopt the "tickless" (no empty loop) kernel to enable the processor to run at low power consumption.

Energy consumption is very important for all operating systems. For Linux, by extending the battery life, low energy consumption can improve its competitiveness in the field of laptops and servers for Windows and reduce the cost of electricity.

The tickless kernel is not the only plan to improve Linux energy efficiency. In March May, Intel released a software called PowerTop. This is very important, Illuminata analyst Harf said about the energy conservation program.

Some Linux development takes several years to be accepted by the mainstream market, but the "tickless" kernel is entering the mainstream Linux version. Speaking of the new kernel, thowaz, the father of Linux, said that most of the re-design work has been completed. He said that for advanced software, the value of PowerTop cannot be measured.

Fan Dewen, a Linux kernel programmer, said that although more work needs to be done, considerable progress has been made. He said lab tests showed that the energy consumption of Linux laptops was reduced by 15%-25% compared with the code used three months ago.

Although not the only power-consuming computer, the power-consuming processor usually exceeds 100 watts. In addition, the heat dissipation fan also needs power to blow away the heat produced by the processor. However, in the past few years, chip vendors have enabled processors to run at low power consumption. When the CPU clock frequency decreases, the voltage and energy consumption will also decrease.

However, the operating system kernel is not doing well in energy saving. One of them is that the software often puts the operating system kernel in the "alert" state without any need. Another problem is that the kernel itself will waste energy. Intel's software can detect the first type of problems, while the "tickless" kernel can solve the second type of problems.

2.6.21 Linux kernel supports the "tickless" technology, which has been applied to Fedora

7. Fan Dewen said that version 2.6.21 Linux kernel can save a lot of energy consumption. In the most energy-saving status, Intel's mobile chip consumes 1.2 watts, and the "tickless" enables the processor to run in the most energy-saving status.

The tickless kernel still records the time, but uses different methods. The kernel does not frequently check whether any work needs to be completed. when the work needs to be completed, the kernel schedules the hardware to issue an interrupt request.

The tickless kernel has another indirect benefit in energy saving: the better use of virtual technology means that virtual software will not be interrupted too much and unnecessary.

Michael, editor of Phoronix website, found that the tickless kernel can reduce energy consumption from 28 watts to 26 watts on IBM's ThinkPad R52, which configures Pentium M and runs Fedora 7. He said that the tickless kernel, coupled with chip-level energy-saving technology, can prolong battery life and reduce heat.