Write a function to cause a thread to wait

Danzy83

Hi, I have written a function to cause a thread to wait for a given time. But the problem is that If this function is called, I notice from task manager (in Windows) that the CPU Usage shoots up to 100 percent. But if I rather use the Windows function Sleep(), the CPU Usage falls back to around 2%, 3%, and 4%. The following is how I wrote the function, with the header file included. void Wait(clock_t milliseconds) { clock_t delay_time = milliseconds + clock(); while (delay_time > clock()) ; return; } I don't know why my CPU usage shoots up to 100% when I use this function rather than Windows Sleep() function. I don't want my application to assume the use of Windows. Please help.

CPallini

Dan_K wrote:

that the CPU Usage shoots up to 100 percent

No wonder: you're using the CPU, aren't you? That's not the best way to pause an application on a multitasking system. :)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong. -- Iain Clarke
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Luc Pattyn

You should upgrade your hardware. If you buy a dual-core system, it will become twice as efficient: the CPU load will be around 50%. Or go for a quad-core and see it sitting idle with a load of a mere 25%. If you don't like that idea, you should either use a sleep function or a timer. FWIW: you could do both to make absolutely sure. :laugh:

Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles]

I only read formatted code with indentation, so please use PRE tags for code snippets.

I'm not participating in frackin' Q&A, so if you want my opinion, ask away in a real forum (or on my profile page).

Cedric Moonen

Your CPU usage goes to 100% simply because you are actually doing something: the while loop and the checks are operations done by the CPU, and in your case without interruption, so the CPU is always busy.

Cédric Moonen Software developer
Charting control [v3.0] OpenGL game tutorial in C++

CPallini

Cedric Moonen wrote:

so the CPU is always busy

It's the ancient wise's rule: "keep the CPU busy and the brain sleeping..." :-D

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong. -- Iain Clarke
[My articles]

malaugh

All the CPU cycles are going to reaing the clock over and over. If you want to be independant of windows, the function uSleep is Unix the equivelent of Sleep, just add #ifndef WIN32 #define Sleep(x) uSleep(x * 1000) #endif To the top of your code

Lost User

Dan_K wrote:

I don't know why my CPU usage shoots up to 100%

Time to start learning how computers work. ;)

It's time for a new signature.