SDL_PollEvent uses too much processor time?

SDL Development
1

Hi!

I have noticed that using SDL_PollEvent() with SDL_Delay() uses much
more processor time than expected. The program below leaves my
Celeron 1700 on 60% idle. I have a similar program using
PeekMessage() and Sleep() from MS Windows API, and then my processor
is 95% idle.

Does anyone know why is this so?

I use MS VC 6.0 (“Release” settings), SDL 1.2.6.=========================================================

#include <sdl/sdl.h>

int main(int argc,char**argv)
{
SDL_Surface *screen;
SDL_Event event;

 if ( SDL_Init(SDL_INIT_VIDEO) < 0 ) return 0;
 screen = SDL_SetVideoMode(1024, 768, 8, SDL_HWPALETTE |

SDL_FULLSCREEN );
if ( screen == NULL ) return 0;

 while(1){
     if (SDL_PollEvent(&event)==0){
         SDL_Delay(1);
         }
     SDL_Delay(1);
     }

}

2

Kresimir Cosic wrote:

I have noticed that using SDL_PollEvent() with SDL_Delay() uses much
more processor time than expected. The program below leaves my Celeron
1700 on 60% idle. I have a similar program using PeekMessage() and
Sleep() from MS Windows API, and then my processor is 95% idle.

Does anyone know why is this so?

your code on my Athlon 1600+ make 0% cpu use … 99% idle …

3

Kresimir Cosic wrote:

I have noticed that using SDL_PollEvent() with SDL_Delay() uses much
more processor time than expected. The program below leaves my
Celeron 1700 on 60% idle. I have a similar program using
PeekMessage() and Sleep() from MS Windows API, and then my processor
is 95% idle.

Does anyone know why is this so?

i’m not sure, but i think you are are running your test programm as
root. AFAIK, SDL_Delay is implemented using usleep() on linux which does
polling for very short delays, when called by root.

hope that helps …
clemens

4

Hi!

I have noticed that using SDL_PollEvent() with SDL_Delay() uses much
more processor time than expected. The program below leaves my
Celeron 1700 on 60% idle. I have a similar program using
PeekMessage() and Sleep() from MS Windows API, and then my processor
is 95% idle.

Does anyone know why is this so?

I use MS VC 6.0 (“Release” settings), SDL 1.2.6.=========================================================

#include <sdl/sdl.h>

int main(int argc,char**argv)
{
SDL_Surface *screen;
SDL_Event event;

 if ( SDL_Init(SDL_INIT_VIDEO) < 0 ) return 0;
 screen = SDL_SetVideoMode(1024, 768, 8, SDL_HWPALETTE |

SDL_FULLSCREEN );
if ( screen == NULL ) return 0;

 while(1){
     if (SDL_PollEvent(&event)==0){
         SDL_Delay(1);
         }
     SDL_Delay(1);
     }

}

5

At a higher view…

Maybe that’s because SDL is multiplatform and MS Windows API no…> ----- Original Message -----

From: dont_send_here@boring.com (Kresimir Cosic)
To:
Sent: Friday, October 10, 2003 4:46 PM
Subject: [SDL] SDL_PollEvent uses too much processor time?

Hi!

I have noticed that using SDL_PollEvent() with SDL_Delay() uses much
more processor time than expected. The program below leaves my
Celeron 1700 on 60% idle. I have a similar program using
PeekMessage() and Sleep() from MS Windows API, and then my processor
is 95% idle.

Does anyone know why is this so?

I use MS VC 6.0 (“Release” settings), SDL 1.2.6.

#include <sdl/sdl.h>

int main(int argc,char**argv)
{
SDL_Surface *screen;
SDL_Event event;

 if ( SDL_Init(SDL_INIT_VIDEO) < 0 ) return 0;
 screen = SDL_SetVideoMode(1024, 768, 8, SDL_HWPALETTE |

SDL_FULLSCREEN );
if ( screen == NULL ) return 0;

 while(1){
     if (SDL_PollEvent(&event)==0){
         SDL_Delay(1);
         }
     SDL_Delay(1);
     }

}

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