what are "kernal times" on cpu usage graph?

[ledzepp98]

i'm not sure if this belongs in this new forum...but to me, since i don't know the answer, seems like a highly technical question?

ok, in win2k i have the task manager running showing the cpu usage (among other things) and i have the option checked to also show the kernal times (which shows up in red). it is usually close to zero and basically always less than cpu usage (which is at 100% since i run seti in the background). basically, i'm not too sure what the kernel is and i have no idea what the graph is showing me with the kernal time?

 

[Chaotic42]

Well, I'd imagine kernel time is the amount of work the actual kernel is doing.
A *quick* search on Google didn't turn up a whole lot. As for what the kernel is,
it's a layer of abstraction between the hardware and all of your software. It's
the low-level core of the OS.

 

[Noriaki]

<< it's a layer of abstraction between the hardware and all of your software. >>

Actually that's the HAL (in WinNT)

Don't mind me I'm just nitpicking

Seriously though Chaotic42 is right, the Kernel is the very low level OS core functionality. And the Kernel time graph tells you how much time is spent in those functions.

Microsoft has designed Windows NT to be a microkernel (I would question whether or not this is truly the case, but that's not really relevant to your question), and a microkernel tries to do as little in the kernel as possible, delegating as much as possible to User processes. Even Virtual Memory is a user process in a microkernel archtecture.

Anyways, this Microkernel philosophy which WinNT is designed to is the reason your kernel time is so low. It tries to keep out of the kernel as much as possible.

 

[artfuIDodger]

technically, the operating system environment created by w2k is divided into two distinct layers: user mode and kernel mode. user mode is where all
user-interactive processes are launched. kernel mode is where all system-level activities occur. these modes are direct equivalents to ring 0 (kernel mode) and ring 3 (user mode) of the ring-based system architecture philosophy, which divides the functions of an operating system into distinct layers or rings that define or describe the level of system protection afforded by that layer. kernel (ring 0) processes can interact directly with hardware, whereas application (ring 3) processes are completely isolated from hardware.

 

[Burn]

Kernel: Processor Usage (%)

The percent of processor time that is not spent idle. This value is approximate.

This was from MS Help.

 

[Schlocemus]

Yes, it is good to have low kernel time

 

[AlexMc]

The red kernel mode part of the graph shows the amount of time that applications are using operating system services. The green section is known as user mode, it shows the time spent running threads within application code.

 

[Nevo]

AlexMC is the most correct reply.

Most programs spend most of their time in user mode. In user mode, they're running in isolated memory space and can't hurt the system as a whole.

Occasionally, a program must accomplish a task that cannot be done in user mode. For instance, say, dialling a phone number on a modem. Because this involves transferring data directly to a piece of hardware, and the kernel prohibits user mode from touching the hardware, this can't be done in user mode.

So, the application makes a special call that the OS traps. This trap causes a context switch into kernel mode, where the OS can perform this task on the application's behalf.

All apps will switch between user mode and kernel mode. The entry into kernel mode is carefully guarded by the OS and only occurs under very specific, well-controlled mechanisms. The kernel finishes what the app needs done and quickly puts the app back into user mode.

Note that even though kernel mode code is running, it is still running in the context of the application that made the system call.

As Alex said, this is basically time that the application has spect calling system services.