libvisual-devel

[Libvisual-devel] VisTimer module

[Duilio J. P. <dp...@fc...>]

I have implemented visual_time_usleep(), so now
we can start working on timed morph.

Bye,
Duilio.

Re: [Libvisual-devel] VisTimer module

[Vitaly V. B. <vit...@us...>]

Hello,

On 04 Sep 2004 15:16:17 -0300
Duilio Javier Protti <dp...@fc...> wrote:

> I have implemented visual_time_usleep(), so now
> we can start working on timed morph.

Just note please that 2.4 and 2.6 kernels behave differently here.
2.4 kernel can wakeup only 50 times a second while 2.6 500 times,
I beleive.

In other words

while(1){
	/* do nothing */
	usleep(1);
	calculate_fps();
}

will (well, should ;) result in 50 FPS on 2.4 kernel.

Not sure if select() will work correctly, probably not.

To implement precise usleep() gettimeofday() should be used, imo.

-- 
Vitaly
GPG Key ID: F95A23B9

[Libvisual-devel] Re: VisTimer module

[Duilio J. P. <dp...@fc...>]

> Not sure if select() will work correctly, probably not.

select() will work right, but only on Linux :-(

I will add this check on future, so usleep we will use 
select only on Linux systems.

> To implement precise usleep() gettimeofday() should be used, imo.

gettimeofday() can be used to get time, but the problem is
how to wait until the time has elapsed. "Busy waiting" is not 
a good idea, and is the only option until we will get some
other way to go to sleep (VisThread in future?). But select()
does this sleep for us, and doesn't consume process CPU cycles.

Regards,
Duilio.

Re: [Libvisual-devel] Re: VisTimer module

[Dennis S. <sy...@yo...>]

Aight, so we need some macros to check the platform, maybe
rename LV_WIN32 to LV_OS_WIN32 and add extra macros
for other platforms ?

Duilio would you mind looking into this ?

Vitaly, it's better not avoid usleep btw because
of the wakeup ticks ?

Busy waiting is indeed not a good idea, how can we solve
this using threading Duilio ? (* note to self, I should
buy the pthreads book :))

Cheers,
Dennis


On Sun, 2004-09-05 at 17:26 -0300, Duilio Javier Protti wrote:
> > Not sure if select() will work correctly, probably not.
> 
> select() will work right, but only on Linux :-(
> 
> I will add this check on future, so usleep we will use 
> select only on Linux systems.
> 
> > To implement precise usleep() gettimeofday() should be used, imo.
> 
> gettimeofday() can be used to get time, but the problem is
> how to wait until the time has elapsed. "Busy waiting" is not 
> a good idea, and is the only option until we will get some
> other way to go to sleep (VisThread in future?). But select()
> does this sleep for us, and doesn't consume process CPU cycles.
> 
> Regards,
> Duilio.