Does kernel affect computing power

1.

Let's talk about it in terms of living conditions:

1. instrial control equipment, embedded devices (including smart phones, routers, switches, load balancers, smart home, etc.) are almost the world of Linux kernel system

2. supercomputer is almost monopolized by Linux kernel system

3. the first choice of large Internet enterprise servers (network, Sina, Taobao, Amazon, Wal Mart, etc.)

4. more than 80% of the basic platforms of cloud server use Linux kernel system (here refers to the basic platform, not the cloud server used by users)

it can be said that a lot of things around you are related to the Linux kernel. The Android mobile phone you are holding, you are browsing web pages, you are brushing Taobao, you go to the bank counter to get money, the intelligent service of the bus you take, the on-board system of your car, and even the 3G and 4G network you are using now, all of which are inseparable from the participation of Linux

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2. The mobile phone can completely upgrade the system version by brushing, and it can't brush the running memory and kernel alone

users can choose to use the software, such as swipe wizard, swipe master and so on

first, download software such as swipe wizard on the computer and back up data such as mobile phone address book

turn on the USB adjustment of the mobile phone and connect it to the computer

start the brush software, and select a brush after successful connection

follow the software prompts to download the required ROM

after entering the one button brushing machine, wait patiently, and when prompted that the brushing machine is successful.

3. Drivers are part of the kernel. To be exact, it is a component of the kernel. A kernel without drivers is also called a kernel, and this is what we often call a kernel. There are no more than five things the kernel should do. 1. Memory management 2. Virtual file system 3. Process scheling 4. Network interface 5. Interprocess communication driver is more like an extension component of kernel to help

4. RedHat provides a very good way for administrators to change kernel parameters when the system is running without rebooting the system. This is achieved through the / PRC virtual file system/ Most of the kernel parameters are stored in the directory of proc / sys, and are designed to be changed while the system is running. Next, we take the IP forwarding function of the kernel as an example to illustrate two methods of modifying kernel parameters when the system is running. IP forwarding is to allow the system to pass the network for the data packets whose source and destination are not local. Red hat blocks this function by default. It is necessary to turn on this function when the local machine is used as router or NAT. Method 1: modify the content of kernel parameter file under / proc, and directly modify the kernel parameter IP_ Forward corresponds to the file / proc / sys / net / IPv4 / IP under / proc_ forward Use the following command to view the IP address_ Forward file content: # cat / proc / sys / net / IPv4 / IP_ The default value of this file is 0, which is to prohibit IP forwarding. If it is changed to 1, the IP forwarding function will be enabled. The modification command is as follows: # echo 1 & gt/ proc/sys/net/ipv4/ip_ The forward modification will take effect immediately, that is, the kernel has turned on the IP forwarding function. However, if the system restarts, it will return to the default value of 0. If you want to permanently open it, you need to modify the content of the / etc / sysctl.conf file. Method 2: modify the / etc / sysctl.conf file. By default, a variable in the sysctl.conf file is net.ipv4.ip_ Forward = 0, change the following value to 1, and then save the file. Because the initialization script / etc / rc.d/rc.sysinit will read the contents of / etc / sysctl.conf file every time the system starts, the IP forwarding function will be turned on every time the system starts after modification. But only modifying the sysctl file will not take effect immediately. If you want to make the modification take effect immediately, you can execute the following command: # sysctl – P when modifying other kernel parameters, you can add corresponding variables to the / etc / sysctl.conf file. The following describes the corresponding relationship between the kernel file under / proc / sys and the variables in the configuration file sysctl.conf, Since the kernel parameters that can be modified are in the / proc / sys directory, the variable name of sysctl.conf omits the front part of the directory (/ proc / sys). According to the following two simple rules: 1. Remove the front part of / proc / sys; 2. Change the slash in the file name to a dot. These two rules can convert any file name in / proc / sys to a variable name in sysctl. For example, / proc / sys / net / IPv4 / IP_ forward ＝ net.ipv4.ip_ Forward / proc / sys / kernel / host name = "kernel.host name you can use the following command to query all modifiable variable names # sysctl – A. here are some simple kernel parameters: 1. / proc / sys / kernel / SHMMAX. This file specifies the maximum size of shared memory segment allowed by the kernel. 2. / proc / sys / kernel / threads Max this file specifies the maximum number of threads that the kernel can use. This file allows you to configure the network host name.

5. I used to upgrade the Ubuntu system in the automatic update, and I really won't upgrade the kernel, but we can choose to manually upgrade and install the new kernel.

1 first, search the command line for the current kernel that can be upgraded, for example, we need to search the 3.19 version of the kernel, Use the following command:
apt cache search 3.19.0
2, and then find the name of the kernel version to be upgraded in the result list. For example, the linux-image-3.19.0-21-generic kernel is the latest, We can use the following commands to install and upgrade the Linux kernel:
sudo apt get install linux-headers-3.19.0-21 linux-headers-3.19.0-21-generic linux-image-3.19.0-21-generic linux-image-extra-3.19.0-21-generic
after successful installation, the system will use the latest kernel by default. Use the command, uname - A to view the information of the Linux kernel being used

6. Different kernel will affect the speed of mobile phone
the kernel is the basic access program of the mobile phone hardware, which is equivalent to the BIOS of the computer. Kernel is the core of the mobile phone operating system, responsible for the operation of the system, different kernel can make the mobile phone with different operating speed, especially for the power consumption and calorific value control of the mobile phone has very different effect! Relatively speaking, the cell phone has a lot of heat, hot hands, and the battery is not used. That's because it uses an inefficient kernel.

7. Distributed file system has the ability of remote file access and transparent access to files distributed on the network. Linux is a computer operating system. The name of the kernel of the Linux operating system is also "Linux, uocyzq"

8. Die, also known as kernel, is the most important part of CPU. The core of the CPU is the raised chip, which is made of monocrystalline silicon by a certain proction process. All the calculation, receiving / storing commands and processing data of the CPU are executed by the core. All kinds of CPU cores have fixed logic structure. The first level cache, second level cache, execution unit, instruction level unit, bus interface and other logic units will have a scientific layout. From the al core technology itself, what is al core? There is no doubt that al kernel should have two physical computing cores, but the design and application of these two cores have a lot to do. According to the existing data, amd Opteron processor was designed with a second core in mind from the beginning. The two CPU cores use the same system request interface SRI, HyperTransport technology and memory controller, and are compatible with the 940 pin interface used by the 90nm single core processor. But Intel's al core is just using two complete CPU packaged together, connected to the same front-end bus. It can be said that AMD's solution is really "al core", while Intel's solution is "al core". It is conceivable that such two cores will inevitably lead to bus contention and affect performance. Not only that, but also for more core integration in the future, because it will aggravate the processor contention for front-end bus bandwidth, and become the bottleneck of improving system performance, which is determined by the architecture. Therefore, it can be said that AMD's technical architecture has laid a solid foundation for the realization of al core and multi-core. Amd direct connection architecture (that is, the CPU core is directly connected to the external I / O through the super transmission technology, not through the front-end bus) and the integrated memory controller technology make each core have its own cache available, and each core has its own dedicated lane through I / O. there is no resource contention problem, so it is easier to realize al core and multi-core. Intel has multiple cores that share the L2 cache and use the front-end bus together. When the number of cores increases and the processing capacity of the cores increases, just like the large communities developed in the suburbs of Beijing now, when multiple communities use the same urban expressway, they will definitely encounter traffic jams
References: http://bbs.gaoe.net/dispbbs.asp?boardid=6&id=1364

9. What's the impact? It's just an ordinary software. If you don't open it, you won't consume resources