A block-related memory management problem found in my friend's log on ios is very strange. Please help me to answer it !, Iosblock

A block-related memory management problem found in my friend's log on ios is very strange. Please help me to answer it !, Iosblock

Http://blog.csdn.net/fengsh998/article/details/38090205

The following is my reply in this article. The same Code just changed the definition of variables from local variables to member variables of the class and found a big difference. At present, no clear answer has been found, please take a look!

Everyone's help

When we use the Windows XP operating system, the system slows down when we use it. When we look at "Task Manager", we find that the CPU usage reaches 100%. How did this happen? In this article, I will explain why the system resource usage reaches 100% from three aspects: hardware, software, and virus. CPU usage is usually 100%, and the main problems may occur in the following aspects:
Nine possibilities of high CPU usage
1. Anti-virus software faults
The new versions of KV, Kingsoft, and rising all add random monitoring of web pages, plug-ins, and emails, which undoubtedly increases the burden on the system. Solution: Basically there is no reasonable solution. Try to use the least monitoring service or upgrade your hardware.

2. the driver has not been certified, resulting in 100% CPU resource usage
A large number of Beta drivers are flooding the Internet, leading to hard-to-find fault causes. Processing Method: especially for graphics card drivers, it is recommended that you use a Microsoft-certified or officially released driver and strictly check the model and version.

3. caused by viruses and Trojans
A large number of worms rapidly replicate within the system, resulting in a high CPU usage rate. Solution: use reliable anti-virus software to thoroughly clean up the system memory and local hard disk, and enable the system setting software to check for programs with startup exceptions. Update and Upgrade anti-virus software and firewall regularly to enhance anti-virus awareness and master the correct anti-virus knowledge.

4. Right-click Control Panel-Administrative Tools-SERVICE-rising realtime monitor service and choose manual.

5. Start->; Run->; msconfig->; Start, close unnecessary startup items, and restart.

6. view the "svchost" process.
Svchost.exe is a core process of Windows XP. Svchost.exe not only appears in Windows XP, but also exists in the Windows System Using ntinner. Generally, in Windows 2000, the number of svchost.exe processes is 2, while in Windows XP, the number of svchost.exe processes has increased to 4 and more.

7. View network connections. This is mainly for NICs.

8. View Network Connections
When a computer with Windows XP installed as a server receives a connection request from port 445, it allocates memory and a small amount of CPU resources to provide services for these connections. When the load is too heavy, the CPU usage may be too high, because there is an inherent trade-off between the number of work items and the response capability. Determine the appropriate MaxWorkItems settings to improve the system response capability. If the set value is incorrect, the server's response capability may be affected, or a user excludes too many system resources.
To solve this problem, we can modify the Registry: in the Registry Editor, expand the [HKEY_LOCAL_MACHINE \ SYSTEM \ CurrentControlSet \ Services \ lanmanserver] branch in sequence, create a New DWORD Value named "maxworkitems" in the right-side window. Double-click the value. In the displayed window, type the following value and save and exit: if the computer has more than 1024 MB memory, type "512". If the computer memory is less than MB, type 256 ".

9. Check if the right-click Windows XP causes 100% CPU usage

Recently, I reported that right-clicking the resource manager will cause 100% of CPU resources to be occupied. Let's see what's going on? Symptoms:
In resource manager, When you right-click a directory or file, you may encounter the following problems:
Any file copy operation may stop at that time
The network connection speed will be significantly reduced
All stream input/output operations, such as using Windows... the remaining full text>

Teach a memory problem

As an indispensable core component of PC-memory, it has gone through many years with DIY hardware. From the 30pin SIMM memory in the 286 era, the 72pin SIMM memory in the 486 era, to the edo dram memory in the Pentium era, and the SDRAM memory in the PII era, DDR memory in the P4 era and DDR2 memory on the 9X5 platform. The memory specification, technology, and bus bandwidth are constantly updated. However, we have reason to believe that the memory upgrade is always the same. Its purpose is to increase the memory bandwidth to meet the increasing bandwidth requirements of the CPU and avoid becoming the bottleneck of High-Speed CPU computing. So what kind of wonderful life is there in the PC field? Let's take a look at the history of memory development.

I. Historical origins-memory stick Concept

If you observe carefully, you can easily see the memory (or cache) on the current DIY hardware. The cache size of the video card, hard disk, or optical drive directly affects the performance of the device, the register may be the most representative of PC hardware devices without RAM. Indeed, if there is no memory, the PC will not be able to run, so the memory will naturally become a key topic discussed by DIY users.

At the beginning, the memory used on the PC was a memory block IC. To enable it to serve the PC, it must be soldered to the motherboard, but this also brings problems to the later maintenance, because once a Memory IC is broken, it must be soldered before replacement, because the connected IC cannot be easily obtained, at the same time, the user does not have the welding knowledge (the welding technology must be mastered, and the risk is also high), which seems to be too troublesome to maintain.

Therefore, PC designers have introduced a modular bar-mounted memory, each of which is integrated into multiple memory ICS, and the corresponding memory slots are also designed on the motherboard, in this way, the memory is easily installed and disassembled at Will (1), and the memory maintenance and upgrade become very simple, which is the source of the memory "entry.
The main function of Memory (RAM) is to save data and commands. We can write data to the RAM memory at the same time, or read data from RAM. Since memory has always been one of the largest performance bottlenecks in the system, the improvement of memory technology is even more exciting than that of CPU and other technologies.
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I will not re-post the above parts. I personally think it is very comprehensive in the following URL:
Www.incpc.net/Html/histroy/20060907817.html

For your reference, although I do not support writing papers and moving something from the Internet.

At the earliest design of the DOS operating system, the PC hardware system only supports 1 M bytes of addressing space, so DOS can only manage a maximum of 1 M bytes of contiguous memory space. In this 1 M memory, only K is reserved for applications. They are called regular memory or basic memory, and the other K is called high-end memory, it is left for video display and BIOS. In, KB of memory was more than enough for micro-computers. People even thought that KB of memory could be used to do anything. It seems a bit ridiculous now, but at the time, it was true.

The current situation is that even if your computer is equipped with a few megabytes or dozens of megabytes of memory, but if you use the DOS operating system, you can only use KB of memory directly, more than 1 MB of memory can be used through some memory management tools. Fortunately, Windows 95 does not have a regular memory limit. All your memory, 8 M or 128 M, can be used directly.

In DOS, the system has the following four types of memory:
Regular Memory (Conventional Memory );
High-end Memory (Upper Memory );
Extended Memory (Expanded Memory );
Extended memory (Ext... the remaining full text>