Red Hat

Hello All

It has been some time sense I was last here.
Hopefully I have a few points left to get this question answered.

I am finding that dstat is a really great tool, but does any one know what "init" and "csw" mean under the column --system--.
I am not able to find anything in the man pages.

Code:

---system--
usr sys idl wai hiq siq| read  writ| recv  send|  in   out | int   csw
 25   2  74   0   0   0|   0     0 |4552B  536B|   0     0 |1198   545

That's not "init" but "int" for interrupts. "csw" means "context switches"

thx. I interpret csw as the number of times the system is switching between threads to service different processes.

I interpret int are strait forward. The number of processes that need immediate attention.

wiki definitions posted below to save folks time if they read this forum post.
Please close this forum thread.


Context switch
From Wikipedia, the free encyclopedia

In computing, a context switch is the process of storing and restoring the state (context) of a process or thread so that execution can be resumed from the same point at a later time. This enables multiple processes to share a single CPU and is an essential feature of a multitasking operating system. What constitutes the context is determined by the processor and the operating system.[1]

Context switches are usually computationally intensive, and much of the design of operating systems is to optimize the use of context switches. Switching from one process to another requires a certain amount of time for doing the administration – saving and loading registers and memory maps, updating various tables and lists etc.


Interrupt
From Wikipedia, the free encyclopedia

In systems programming, an interrupt is a signal to the processor emitted by hardware or software indicating an event that needs immediate attention. An interrupt alerts the processor to a high-priority condition requiring the interruption of the current code the processor is executing. The processor responds by suspending its current activities, saving its state, and executing a function called an interrupt handler (or an interrupt service routine, ISR) to deal with the event. This interruption is temporary, and, after the interrupt handler finishes, the processor resumes normal activities.[1] There are two types of interrupts: hardware interrupts and software interrupts.

Hardware interrupts are used by devices to communicate that they require attention from the operating system.[2] Internally, hardware interrupts are implemented using electronic alerting signals that are sent to the processor from an external device, which is either a part of the computer itself, such as a disk controller, or an external peripheral. For example, pressing a key on the keyboard or moving the mouse triggers hardware interrupts that cause the processor to read the keystroke or mouse position. Unlike the software type (described below), hardware interrupts are asynchronous and can occur in the middle of instruction execution, requiring additional care in programming. The act of initiating a hardware interrupt is referred to as an interrupt request (IRQ).