|
Hi George,
Each of the threads (of all processes taken together) is basically in one of two states:
- can proceed (often called "ready", which does not mean "done" here)
- can't proceed ("waiting" or "blocked")
ON A SINGLE CORE
Of all the ready threads one is actually running, that is the "current thread".
The idle process basically has one thread that never blocks, it is always ready but
has lowest priority, so if all other threads are blocked, then CPU cycles are spent
(or wasted) in the idle thread; if some other thread is ready, there would not be any
idle cycles.
ON AN N-WAY MULTI-CORE
same ideas, but now there are N "current threads", and the idle process holds N idle threads;
if fewer than N non-idle threads are "ready", the remaining cores will execute their idle
thread.
result: a single-thread app will only consume max 50% of available CPU cycles on a
dual-core. The other core may run threads from other apps, and if nothing is ready,
then it idles. Turning the single-threaded app into a dual-threaded app is likely to
improve the app's performance, and to lower the overall CPU's idle percentage.
Luc Pattyn [Forum Guidelines] [My Articles]
This month's tips:
- before you ask a question here, search CodeProject, then Google;
- the quality and detail of your question reflects on the effectiveness of the help you are likely to get;
- use PRE tags to preserve formatting when showing multi-line code snippets.
|
|
|
|
|
Thanks Luc,
Do you think process waiting for I/O will cause system in idle, even if some process seems running (but actually waiting for I/O)?
For example,
1. Hard page fault cauing a lot of page swap I/O;
2. Waiting for network I/O;
3. Waiting for file I/O.
regards,
George
|
|
|
|
|
George_George wrote: Do you think process waiting for I/O will cause system in idle
As I said, a thread that is not ready (as in Thread.Sleep, ManualResetEvent.WaitOne, and
many many more), will cause the next-priority ready thread to run. If none are ready besides
the idle thread(s), then the system becomes idle until a thread becomes ready again
(because an I/O operation completed, or a delay expired).
The key word is "waiting": if a thread performs some I/O it does not necessarily wait,
e.g. most files accesses are buffered, so adding a char to a file stream is very likely to
be a simple memory operation most of the time; once the buffer is full, or some threshold
is exceeded, the stream may pass its buffer to the next level, say a software cache,
or the disk driver itself; if slow/physical devices get involved, a real wait is probable.
I am getting the impression you have some overall problem and are asking questions at
too low a level; it may be more useful if you explain your app, and the observations that
cause you to wonder about all this (unless it is just out of curiosity of course).
Luc Pattyn [Forum Guidelines] [My Articles]
This month's tips:
- before you ask a question here, search CodeProject, then Google;
- the quality and detail of your question reflects on the effectiveness of the help you are likely to get;
- use PRE tags to preserve formatting when showing multi-line code snippets.
|
|
|
|
|
Thanks Luc Pattyn,
My question is answered. Your patience is appreciated.
regards,
George
|
|
|
|
|
you're welcome.
Luc Pattyn [Forum Guidelines] [My Articles]
This month's tips:
- before you ask a question here, search CodeProject, then Google;
- the quality and detail of your question reflects on the effectiveness of the help you are likely to get;
- use PRE tags to preserve formatting when showing multi-line code snippets.
|
|
|
|
|
|
Does it has anything to do with my original question, what will cause idle process happen (I/O?)?
regards,
George
|
|
|
|
|
if you understand that Idle means Do Nothing, yes, it has to do !!!
|
|
|
|
|
Has to to what?
My question is about what makes idle process happen, not what is idle process.
Any ideas?
regards,
George
|
|
|
|
|
are you doing it voluntarily ?
no one make the Idle Process Happen. it is there as long as Windows runs. if it uses 100% of proc. time, then it's because no other application consumes the CPU. if you see full CPU usage in the task manager, then remark that the idle process uses 0% of the processor...
that's all, there's nothing more to know about it.
|
|
|
|
|
Thanks toxcct,
I agree no one knows exactly how will cause idle process. But this thread is used to discuss in what general scenarios, system idle process will happen. 
Like we have discussed,
1. System is not doing anything;
2. Single thread on multi CPU;
3. I/O (network, file, etc.).
It is appreciated if you could add some more.
regards,
George
|
|
|
|
|
George_George wrote: Are there any other cases which will cause system idle process happen
It "happens" as a result of the other processes not doing anything (i.e., it's what they are not). In other words, if you sum the CPU Usage of all processes, subtract from 100, the result would be the System Idle Process. Of course, I'm sure you already knew this.
"Normal is getting dressed in clothes that you buy for work and driving through traffic in a car that you are still paying for, in order to get to the job you need to pay for the clothes and the car and the house you leave vacant all day so you can afford to live in it." - Ellen Goodman
"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne
|
|
|
|
|
Thanks DavidCrow,
I agree.
regards,
George
|
|
|
|
|
|
Looks great, Hamid!
Very helpful. If there could be the a list of reasons which will cause idle process to have a non-neglectible percentage will be better.
regards,
George
|
|
|
|
|
You're welcome. 
|
|
|
|
|
I am trying to develop a COM executable which implements the functionality in the IHWEventHandler interface . I was unsure if the IDE supports creating a co-class implementing the functions defined in IHWEventHandler.
In other words , I started with a new ATL project , which creates the boiler-plate code for housing the COM object , however I was unsure as to how to add a CoClass ( that implements the functionality of IHWEventHandler) from within the IDE.
I have tried Add->ATL Object --> Simple Object , however I am not sure where and how I can specify ( from the IDE) that the new class that I create will derive from
public IHWEventHandler
Any help is appreciated.
|
|
|
|
|
Hi all,
I have a web application on Visual Studio 2005, Windows Xp Pro, and I want my web application to handle requests for JPG images, how can I set the configuration for the application to have my application receive and serve requests for JPEG files?
Thank you
Mohammad
And ever has it been that love knows not its own depth until the hour of separation
|
|
|
|
|
Hi,
i'm using the windows media player as activeX object in a C#
application. I want to change the "Video border color"
(Windows Media Player->Menu Tools->Options->Performance->Advanced)
in my application. I cannot find the right options in the msdn library
to change the color from my application.
It's because i want to change the background color of the media player
if a video is changed during playback.
Can please someone tell me how to to this?
regards,
Lucas
|
|
|
|
|
If your question is about C# you must ask on the correct forum because here VC++ forum. 
|
|
|
|
|
damn it! Sorry, i'll post it in the correct forum.
|
|
|
|
|
|
I'm implementing a model class that emulates a tree or hierarchy. A value is stored as a variant type structure, and you get access to a value with a key thats some unsigned int generated when you insert the value into the model. When you insert a value you specify a "parent" key.
So my question is: what's the best thing to use to implement this? Could I just use a std::map to store the key/values, and then a std::multimap<key,key> to store the parent/child relationships? Is there a simpler way?
Cheers
Jim
¡El diablo está en mis pantalones! ¡Mire, mire!
Real Mentats use only 100% pure, unfooled around with Sapho Juice(tm)!
SELECT * FROM User WHERE Clue > 0
0 rows returned
Save an Orange - Use the VCF!
VCF Blog
|
|
|
|
|
Does anyone know why on like 3 of 40 of the computers my company has, the controls placed on a dialog programmatically via MoveWindow are sized different than if they were just placed in the .RC file with the Resource Editor?
I have an image to show what I mean. On the right hand side I have what a normal machine looks like. on the left hand side is a screwed up machine( you'll notice all the top controls which are placed in the resource editor are much larger, where the bottom controls which are placed with MoveWindow function end up in the correct place)
http://www.john-moses.com/img/artviewer_bug.jpg[^]
So I have a dialog that has several controls on it, most of which don't need to be resized, only 2 of the controls on the dialog need to be resized. All the controls on the dialog that don't need to be resized I just place in the .RC file with the Resource Editor, and don't bother making member variables for. For the 2 controls that need to resizing, I'll place in the Resource Editor, but in the OnSize function I'll call MoveWindow on the 2 control's member functions to resize them.
This works just fine on like 98% of the computers are my company, but for like 3 people, for some reason this mix of Resource Editor/MoveWindow placed controls causes some kind of visual bug.
Any Ideas what could cause this?
I looked at the machines "Desktop Properties -> Display Properties -> Advanced", and all our fonts and sizes are the same.
We all do have different processors and video cards, nothing we can do about that.
We're all running Windows XP Pro
eh?
|
|
|
|
|
The coordinates in an RC file are expressed in dialog units. See here[^] for details on how to deal with them. Alternatively use place-holders in the .rc file and then use the GetWindowRect and MapWindowPoints APIs to get the coordinates in pixels (relative to the window's client area).
Steve
|
|
|
|
|
General 
News 
Suggestion 
Question 
Bug 
Answer 
Joke 
Praise 
Rant 
Admin 
Submit an article or tip
