A system can be running unusually slow because a process (program) is demanding all of the computer's processing power (CPU usage) or is using all of the computer's memory.
By default, processes owned by the current user that are using a lot of CPU or memory are near the top. This means that any misbehaving programs should be near the top and easily visible. For example:
To end the process that is misbehaving, click on the process to select it and press the <menuchoice>Kill Process...</menuchoice> button. This will send a polite request to the program, asking it to close.
===I can't kill it - it just won't die!===
===我杀不了它 - 它不死！===
Thankfully it's fairly rare, but just occasionally you may meet this. If the process is misbehaving it may ignore your request to end, so we may need to force the program to end immediately. Doing this may result in any documents etc that the program had opened but not saved. To do this, right click on the process and choose <menuchoice>Send Signal</menuchoice> then choose <menuchoice>Kill (KILL)</menuchoice>.
Sometimes even this will not kill the process, or the option will not be given. This can happen, for example, in '''vuze''' with certain kernels. If the process or one of its threads gets caught in a kernel bug then it can end up being stuck trying to execute a kernel operation and being completely unkillable. Often there is no solution to this other than rebooting the machine.
Processes which are in a Zombie state are already dead, and so cannot be killed. The system keeps them around until their parent process notices, which is usually a very short amount of time. Seeing a Zombie process usually indicates that the parent process has stopped responding.
If you want to kill a particular window that has frozen up, simply press <keycap>Ctrl + Alt + Esc</keycap> at any time. The mouse cursor should turn into an image of a skull and cross bones. Now click the window that you want to kill. Note that this will kill the application immediately, and you may lose any unsaved data.
如果你想要杀死某个特定的已经冻结停止响应的窗口，只需按下<keycap>Ctrl + Alt + Esc</keycap> 。鼠标指针会变成骷髅头加十字交叉骨头图片。然后点击想杀掉的窗口。注意这会直接杀死程序，你可能会丢掉未保存的数据。
==What's the difference between Memory and Shared Memory?==
==内存和共享内存有什么区别？==
The Memory column shows approximately the amount of memory (RAM) that the process is using by itself, privately. The Shared Memory column is approximately the memory that is, or could be, shared with other programs. For example, the KDE libraries are used by all KDE programs and so are loaded into memory only once.
From KDE SC 4.4, you can right-click on a process and view the <menuchoice>Detailed Memory Information</menuchoice> for the process to get more accurate readings.
The "Memory" column shows the value of VmRSS - Shared, and so is generally lower than the values shown by '''top''' etc. This does not include memory backed I/O pages, and does not include memory used by the x server to store any pixmaps used by the application. This value is often called the Unique RSS size, or URSS. This approximates the value shown as Private memory usage in the <menuchoice>Detailed Memory Information</menuchoice>.
共享内存与 top 命令中的 SHR 列一样，会有少许不准确。接近<menuchoice>内存详细信息</menuchoice>中显示的共享内存使用（Shared memory usage）的值。
The Shared memory is the same as the SHR column in top and can be somewhat inaccurate. This approximates the value shown as Shared memory usage in the <menuchoice>Detailed Memory Information</menuchoice>.
Specifically the process list parses <code>/proc/pid/stat</code> whereas the <menuchoice>Detailed Memory Information</menuchoice> dialog parses <code>/proc/pid/smaps</code>.
==如何查看一个进程内存的更多详细信息？==
==How do I view more Detailed Memory Information about a process?==
从 KDE SC 4.4 开始，你可以在列表中选择一个进程，右击进程，选择<menuchoice>详细内存信息</menuchoice>，会得到类似这样的信息：
From KDE SC 4.4 you will be able to select a process in the table, right click on the process, and choose <menuchoice>Detailed memory Information</menuchoice>, and get something like:
Line 70:
Line 67:
==Why do values in Detailed Memory Information not match the process list?==
==为什么 ''详细内存信息'' 中的值跟进程列表中不一样？==
The process list in System Activity is using an approximation to gather the values. The <menuchoice>Detailed Memory Information</menuchoice> gives more accurate values.
==Why is the "Xorg" process using so much memory?==
==为什么'Xorg'进程占了那么多内存？==
This is the process that displays all the other applications. Its memory usage includes all the memory used on the video card to store all the pixmaps (images) from applications.
这个进程负责显示所有其他程序。它的内存占用包括了显卡中储存程序中图形映射 pixmaps 的显存。
In general you do not need to worry about the memory usage of Xorg.
一般来说你不用去关心Xorg的内存占用。
==How do I see the PID of a process?==
==我怎样能看到进程的PID？==
If you want to see the ''PID'' of a single process, hover the mouse cursor over the name of the process. The PID will be shown in the tooltip.
Right click on the column headings, and choose <menuchoice>Show Column IO Read</menuchoice> and again for <menuchoice>Show Column IO Write</menuchoice>. It will now show the amount of data being sent to or from the hard disk.
[[File:Systemactivity_io.png|center|500px]]
[[File:Systemactivity_io.png|center|500px]]
By right clicking on the column header you can chose whether you want to view the actual amount of data being written or read from the hard disk (the default), or whether you are interested in seeing how much data the application is sending or requesting from a file.
通过在列标题上右击鼠标，可以选择查看磁盘的读写数(默认)还是文件的读写数。
Data requested and actual data read from the hard disk are not equivalent - for example, if two applications read from the same file the operating system does not need to read from the actual hard disk twice - it can just read it once and remember it for a short while. Similarly, if one process writes to a file, but then another process writes over the top of that same file, there's no point writing the first version of the file to the actual hard disk.
process just for convenience to make it easier to see processes that are quit.
The values for the CPU usage, Memory usage, etc are just the values from when the process was last seen alive. A process that has ended does not take up any resources (it uses no CPU, memory etc).
==What are all of these processes owned by root and taking up no memory?==
==这些用户名全是 root 并且不占用内存的进程是什么？==
These are kernel threads. They exist only inside the kernel, and exist to allow the kernel to perform multiple tasks in parallel.
这些是内核线程。它们只存在内核中，内核使用它们并行执行多个任务。
They are shown because occasionally they can be a cause of heavy CPU usage. For example, under a heavy load, and with bad drivers, a network card can produce a huge number of interrupts, resulting in a high CPU usage in the '''ksoftirqd''' kernel thread.
个别时候，它们会引起高CPU使用率，程序会显示它们。例如处于重负载时，如果安装了不合适的驱动，网卡会产生大量的中断，导致了 '''ksoftirqd''' 内核线程有很高的 CPU 占用。
Likewise, a high CPU usage in '''kjournald''' can indicate that DMA transfer is not enabled on the hard disk.
此外，'''kjournald''' 中的高 CPU 占用率表明硬盘的 DMA 传输特性没启用。
==Why do I have so many processes?==
==为什么我的系统有那么多进程？==
A normal average-user system has around 150 to 200 processes with strange sounding names. It would be nice to setup a wiki page giving a short description of each of these processes, but so far nobody has done this. [[Image:Face-smile.png|11px]]
==Why is OpenOffice.org not showing up as a graphical program?==
==为什么 OpenOffice.org 没有作为图形程序显示出来？==
Before version 3.3, OpenOffice.org did not correctly implement the window standards. Specifically, their windows did not set _NET_WM_PID to link the windows to the process. This is now [http://www.openoffice.org/issues/show_bug.cgi?id=47904 fixed] in OpenOffice.org 3.3.
==Why is gvim showing up strangely as a graphical program?==
==为什么 gvim 奇怪的按照图形程序显示?==
This is a fault with the GVim program. GVim does not correctly implement the window standards. Specifically, when it starts up it forks a new process to avoid hanging the shell that it ran from. But it sets the _NET_WIN_PID property to the previous PID. The authors have been notified but have not fixed this yet.
「系统活动」图标就会弹出它。
按钮可以激活“这是什么功能”，解释信息代表的意思。
